Co-reporter:Takenari Sato, Takumi Yoshida, Hamad H. Al Mamari, Laurean Ilies, and Eiichi Nakamura
Organic Letters October 6, 2017 Volume 19(Issue 19) pp:
Publication Date(Web):September 14, 2017
DOI:10.1021/acs.orglett.7b02778
We report here a manganese-catalyzed C–H methylation reaction of considerable substrate scope, using MeMgBr, a catalytic amount of MnCl2·2LiCl, and an organic dihalide oxidant. The reaction features ambient temperature, low catalyst loading, typically 1%, high catalytic turnover reaching 5.9 × 103, and no need for an extraneous ligand and illustrates a unique catalytic use of simple manganese salts for C–H activation, which so far has relied on catalysis by manganese carbonyls.
Co-reporter:Eiichi Nakamura
Accounts of Chemical Research June 20, 2017 Volume 50(Issue 6) pp:1281-1281
Publication Date(Web):May 8, 2017
DOI:10.1021/acs.accounts.7b00076
ConspectusA molecule is a quantum mechanical entity. “Watching motions and reactions of a molecule with our eyes” has therefore been a dream of chemists for a century. This dream has come true with the aid of the movies of atomic-resolution transmission electron microscopic (AR-TEM) molecular images through real-time observation of dynamic motions of single organic molecules (denoted hereafter as single-molecule atomic-resolution real-time (SMART) TEM imaging). Since 2007, we have reported movies of a variety of single organic molecules, organometallic molecules, and their assemblies, which are rotating, stretching, and reacting. Like movies in the theater, the atomic-resolution molecular movies provide us information on the 3-D structures of the molecules and also their time evolution. The success of the SMART-TEM imaging crucially depends on the development of “chemical fishhooks” with which fish (organic molecules) in solution can be captured on a single-walled carbon nanotube (CNT, serving as a “fishing rod”). The captured molecules are connected to a slowly vibrating CNT, and their motions are displayed on a monitor in real time. A “fishing line” connecting the fish and the rod may be a σ-bond, a van der Waals force, or other weak connections. Here, the molecule/CNT system behaves as a coupled oscillator, where the low-frequency anisotropic vibration of the CNT is transmitted to the molecules via the weak chemical connections that act as an energy filter. Interpretation of the observed motions of the molecules at atomic resolution needs us to consider the quantum mechanical nature of electrons as well as bond rotation, letting us deviate from the conventional statistical world of chemistry.What new horizons can we explore? We have so far carried out conformational studies of individual molecules, assigning anti or gauche conformations to each C–C bond in conformers that we saw. We can also determine the structures of van der Waals assemblies of organic molecules, thereby providing mechanistic insights into crystal formation—phenomena of general significance in science, engineering, and our daily life. Whereas many of the single organic molecules in a vacuum seen by SMART-TEM are sufficiently long-lived for detailed studies, molecules with low ionization potentials (<6 eV) were found to undergo chemical reactions, for example, [60]fullerene and organometallic compounds possibly via a hole catalysis mechanism, where a radical cation of CNT generated under electron irradiation catalyzes the transformation via an electron transfer mechanism. Common organic molecules whose ionization potentials are much higher (>8 eV) than that of CNT (5 eV) remain stable for a time long enough for observation at 60–120 kV acceleration voltage, as they are not oxidized by the CNT radical cation. Alternatively, the reaction may have taken place via an excited state of a molecule produced by energy transfer from CNT possessing excess energy provided by the electron beam. SMART-TEM imaging is a simple approach to the study of the structures and reactions of molecules and their assemblies and will serve as a gateway to the research and education of the science connecting the quantum mechanical world and the real world.
Co-reporter:Hirohisa Nitta, Koji Harano, Mayuko Isomura, Ellen H. G. Backus, Mischa Bonn, and Eiichi Nakamura
Journal of the American Chemical Society June 14, 2017 Volume 139(Issue 23) pp:7677-7677
Publication Date(Web):May 25, 2017
DOI:10.1021/jacs.7b01596
Micellization in water and reduction of the surface tension at water interfaces with air and oil are two archetypical properties of surfactants, caused by self-aggregation and Gibbs monolayer formation at the interfaces, respectively. We present here a new type of amphiphiles that possess a conical shape consisting of a hydrophobic apex and five ionic termini at the base of the cone. The conical shape and the high charge density cooperatively impede monolayer formation at the interfaces, hence preventing foaming and emulsification. On the other hand, the conical shape strongly assists micelle formation in water and hemimicelle formation on a solid surface to promote dissolution of nanoparticles such as magnetic nanoparticles and nanocarbons in water. The well-defined shape and charge locations distinguish the new amphiphiles from known polymer amphiphiles that show similar surface activity.
Co-reporter:Yunlong Guo, Wataru Sato, Kazutaka Shoyama, Henry Halim, Yuki Itabashi, Rui Shang, and Eiichi Nakamura
Journal of the American Chemical Society July 19, 2017 Volume 139(Issue 28) pp:9598-9598
Publication Date(Web):June 23, 2017
DOI:10.1021/jacs.7b03856
Solar cells made of lead perovskite crystals have attracted much attention for their high performance, but far less attention as a subject of crystal engineering. Here, we report that citric acid (CA) and chloride anion, working together, modulate crystal growth of CH3NH3PbI3, producing sub-mm-sized cuboid crystals—a morphology more suitable for close packing in a thin film than the commonly observed elongated dodecahedral morphology. By using a 15 wt % CA-doped precursor solution, we formed a single layer of large, flat, and oriented cuboid crystals with minimum crystal domain boundaries and maximum contact with neighboring layers, and fabricated an archetypal inverted-structured device of 4 mm2 area, which showed, reproducibly and with little hysteresis, 16.75% power conversion efficiency (PCE), 26% higher than the PCE obtained for a polycrystalline film made without CA doping. Under weaker irradiation of a 1 cm2 device, the PCE improved from 14.52% (one sun) to 20.4% (0.087 suns). Under illumination with white light emitting diode, a 10 wt % CA-doped device showed PCE of 28.1%, suggesting an advantage of PVK-SCs for indoor applications. Further studies on crystal growth modulation will be beneficial for manufacturing efficient and stable lead perovskite solar cells.
Co-reporter:Rui Shang, Laurean Ilies, and Eiichi Nakamura
Chemical Reviews July 12, 2017 Volume 117(Issue 13) pp:9086-9086
Publication Date(Web):April 5, 2017
DOI:10.1021/acs.chemrev.6b00772
Catalytic C–H bond activation, which was an elusive subject of chemical research until the 1990s, has now become a standard synthetic method for the formation of new C–C and C–heteroatom bonds. The synthetic potential of C–H activation was first described for ruthenium catalysis and is now widely exploited by the use of various precious metals. Driven by the increasing interest in chemical utilization of ubiquitous metals that are abundant and nontoxic, iron catalysis has become a rapidly growing area of research, and iron-catalyzed C–H activation has been most actively explored in recent years. In this review, we summarize the development of stoichiometric C–H activation, which has a long history, and catalytic C–H functionalization, which emerged about 10 years ago. We focus in this review on reactions that take place via reactive organoiron intermediates, and we excluded those that use iron as a Lewis acid or radical initiator. The contents of this review are categorized by the type of C–H bond cleaved and the type of bond formed thereafter, and it covers the reactions of simple substrates and substrates possessing a directing group that anchors the catalyst to the substrate, providing an overview of iron-mediated and iron-catalyzed C–H activation reported in the literature by October 2016.
Co-reporter:Laurean Ilies, Yuki Itabashi, Rui Shang, and Eiichi Nakamura
ACS Catalysis January 6, 2017 Volume 7(Issue 1) pp:89-89
Publication Date(Web):November 22, 2016
DOI:10.1021/acscatal.6b02927
An iron(III) salt, (Z)-1,2-bis(diphenylphosphino)ethene or its electron-rich congener, (Z)-1,2-bis[bis(4-methoxyphenyl)phosphine]ethene, and a zinc(II) salt catalyze the arylation, heteroarylation, and alkenylation of propionamides possessing an 8-quinolylamide group with organoborate reagents in the presence of 1,2-dichlorobutane as oxidant at 70 °C. Stoichiometric experiments provided evidence for the involvement of an organoiron(III) species as a key intermediate for C–H activation and C–C bond formation.Keywords: alkenylation; amide; boron compound; C(sp3)−H activation; iron catalysis; zinc catalysis;
Co-reporter:Kazutaka Shoyama;Wataru Sato;Yunlong Guo
Journal of Materials Chemistry A 2017 vol. 5(Issue 45) pp:23815-23821
Publication Date(Web):2017/11/21
DOI:10.1039/C7TA08042E
This work has chemically addressed the enigmatic effects of water on solar cell devices based on an organic–inorganic hybrid perovskite, i.e., water can exert either beneficial or detrimental effects on device fabrication and device stability. We have examined in detail a known conversion of lead(II) iodide crystals to a polymer strip of a hydrated plumbate dimer in water and analyzed the time course of the conversion of the fiber crystals of the hydrate to perovskite crystals using fiber X-ray diffraction analyses. We found that the first step, the conversion of lead(II) iodide to a plumbate intermediate, is a fast solid-to-solid conversion reaction, and that the second step, the conversion of this intermediate to the perovskite, is also very fast because of easy loss of water. Overall, we propose that the water present as a minute constituent in DMF or DMSO actively participates as a catalyst in the whole reaction scheme, acting in the first step as a hydrated methylammonium to assist the cleavage of Pb–I bridges, and in the second step through quicker loss from a plumbate intermediate because of a lower hydrogen-bond accepting ability than DMF or DMSO.
Co-reporter:Luca Schweighauser, Koji Harano, Eiichi Nakamura
Inorganic Chemistry Communications 2017 Volume 84(Volume 84) pp:
Publication Date(Web):1 October 2017
DOI:10.1016/j.inoche.2017.07.009
•Formation of cubic MOF-5 and layered MOF-2 takes place by different pathways.•Interconversion is only possible through complete destruction of crystal structure.•The study implies that capping agents facilitate the formation of MOF-5 and MOF-2.The synthesis of metal–organic frameworks (MOFs) often exhibits unpredictable complexity. Here, we report that MOF-5 formation at 120 °C takes a pathway different from the MOF-2-like crystal formation at 95 °C, and suggest that their interconversion requires degradation of the whole crystal structure.Download high-res image (110KB)Download full-size image
Co-reporter:Hayato Tsuji and Eiichi Nakamura
Accounts of Chemical Research 2017 Volume 50(Issue 2) pp:
Publication Date(Web):February 6, 2017
DOI:10.1021/acs.accounts.6b00595
ConspectusThe fused polycyclic furan structure is a ubiquitous motif in naturally occurring organic compounds. However, they had been rarely seen in the literature of organic electronic research until very recently, probably because of the lack of stability of simple furans under conditions that the compounds experience in the active layer of the device. Nonetheless, from the viewpoint of molecular structure, furans look to have potential merits as organic semiconductors such as thiophenes, which are more popular in the organic electronic area. For example, the small atomic radius and large electronegativity of oxygen will increase intermolecular molecular orbital (MO) overlap and hence facilitate charge transporting ability in the solid state.In this Account, we describe the molecular design and optoelectronic applications of fused polycyclic furans, such as benzodifurans (BDFs), naphthodifurans (NDFs), and anthradifurans (ADFs). The molecular design that was exploited in this study crucially depends on the synthetic flexibility of a “modular” synthetic strategy that we purposely developed and reviewed in a separate report. Our synthetic strategy comprises two steps carried out in situ: cyclization of an o-alkynylphenol into a zincio benzofuran and its electrophilic Negishi-type trapping to obtain a range of multisubstituted fused furan compounds. These compounds are found to possess electronic structures resembling those of fused polyaromatic hydrocarbons, such as acenes or phenacenes, rather than oxygen-bridged phenylenevinylene, along with unique characteristics: a wide HOMO–LUMO gap originating from the weak aromaticity of the furan rings, an intense photoluminescent character, and mechanofluorochromism.Semiconducting properties of fused furans are also excellent among organic materials: some BDF derivatives show high hole mobility on the order of 10–3 cm2/(V s) in the amorphous state using time-of-flight (TOF) technique. The p-type BDFs exhibit high performance as hole-transporting material in heterojunction organic light-emitting diodes (OLEDs), while carbazole-substituted BDFs (CZBDFs) are ambipolar with well-balanced high carrier mobility for both hole and electron and serve as host materials for full-color electroluminescence in both hetero- and homojunction architectures. More π-expanded NDFs showed good crystallinity and are effective active materials for organic field-effect transistors (OFETs) with a high hole mobility of up to 3.6 cm2/(V s) using a solution process. These studies have illustrated the high potential of fused polycyclic furans in organic electronics research, which thus far have attracted much less attention than their thiophene congeners.
Co-reporter:Yunlong Guo;Kazutaka Shoyama;Wataru Sato
Advanced Energy Materials 2016 Volume 6( Issue 6) pp:
Publication Date(Web):
DOI:10.1002/aenm.201502317
Co-reporter:Ricardo M. Gorgoll; Koji Harano
Journal of the American Chemical Society 2016 Volume 138(Issue 30) pp:9675-9681
Publication Date(Web):July 12, 2016
DOI:10.1021/jacs.6b05414
The use of the interior of self-assembled membrane as a template for polymer synthesis and assembly has long attracted the interest of chemists. However, it is difficult to utilize a lipid membrane as a chemical reactor for controlled assembly for polymers because lipid membrane is easily destabilized by loading of extraneous molecules. We found that a several-nanometer-thick bilayer vesicle made by self-assembly of an organic fullerene amphiphile doped with a metathesis catalyst serves as a nanosized chemical reactor in water, where a polymer is synthesized and assembled, depending on the affinity of the growing polymer to the organic groups on the amphiphile. This catalyst–bilayer system can thus control supramolecular assembly of the ester-functionalized polymer product into different nanoscale structures: a nanoparticle made of a single polymer chain and a nanocapsule made of several tens of polymer chains.
Co-reporter:Rui Shang, Laurean Ilies, and Eiichi Nakamura
Journal of the American Chemical Society 2016 Volume 138(Issue 32) pp:10132-10135
Publication Date(Web):August 3, 2016
DOI:10.1021/jacs.6b06908
Iron-catalyzed C–H functionalization of aromatics has attracted widespread attention from chemists in recent years, while the requirement of an elaborate directing group on the substrate has so far hampered the use of simple aromatic carbonyl compounds such as benzoic acid and ketones, much reducing its synthetic utility. We describe here a combination of a mildly reactive methylaluminum reagent and a new tridentate phosphine ligand for metal catalysis, 4-(bis(2-(diphenylphosphanyl)phenyl)phosphanyl)-N,N-dimethylaniline (Me2N-TP), that allows us to convert an ortho C–H bond to a C–CH3 bond in aromatics and heteroaromatics bearing simple carbonyl groups under mild oxidative conditions. The reaction is powerful enough to methylate all four ortho C–H bonds in benzophenone. The reaction tolerates a variety of functional groups, such as boronic ester, halide, sulfide, heterocycles, and enolizable ketones.
Co-reporter:Qifan Yan, Yunlong Guo, Anna Ichimura, Hayato Tsuji, and Eiichi Nakamura
Journal of the American Chemical Society 2016 Volume 138(Issue 34) pp:10897-10904
Publication Date(Web):August 5, 2016
DOI:10.1021/jacs.6b04002
Stabilization of the radical cationic state of a donor molecule by 3-D homoconjugation was probed using a substituted carbon-bridged oligophenylenevinylene backbone (COPV, or 5,5-diarylindeno[2,1-a]indenes). For molecules bearing electron-donating groups as the 5,5-aryl moieties, a one-electron oxidation of the COPV backbone results in delocalization of the cationic charge over the whole molecule with a small reorganization energy. The compounds forming a stable radical cation by 3-D homoconjugation produce a uniform amorphous film and show high short-circuit current, high fill factor, and hence high power-conversion efficiency when used as a hole-transporting layer of an organic–inorganic hybrid lead perovskite solar cell. This material thus shows a performance and stability in air comparable to those obtained with the benchmark material, spiro-MeOTAD.
Co-reporter:Laurean Ilies, Mayuko Isomura, Shin-ichi Yamauchi, Tomoya Nakamura, and Eiichi Nakamura
Journal of the American Chemical Society 2016 Volume 139(Issue 1) pp:23-26
Publication Date(Web):December 22, 2016
DOI:10.1021/jacs.6b10061
Upon zincation of two acidic protons attached to the nitrogen and the sp-carbon atoms, a N-protected 2-ethynylaniline cyclizes to a 2,3-dizincioindole at 120 °C. Driven by the energy gain due to formation of two C–Zn bonds, this reaction occurs smoothly without side reactions, although this transformation is intrinsically endothermic in its bare anionic form. The resulting dizinc intermediate can be functionalized with one or two different electrophiles either inter- or intramolecularly on either C2 or C3 selectively, depending on the choice of catalyst and the electrophiles. This conversion of 2-ethynylaniline to 2,3-dimetalloindole can be applied to an expeditious synthesis of indenoindolone and benzodipyrrole derivatives, which are compounds of interest for medicinal chemistry and materials science, respectively.
Co-reporter:Yunlong Guo; Wataru Sato; Kazutaka Shoyama
Journal of the American Chemical Society 2016 Volume 138(Issue 16) pp:5410-5416
Publication Date(Web):April 7, 2016
DOI:10.1021/jacs.6b02130
Lead perovskite materials such as methylammonium triiodoplumbate(II) (CH3NH3PbI3, PV) are promising materials for printable solar cell (SC) applications. The preparation of PV involves a series of energetically costly cleavages of the μ-iodo bridges via conversion of a mixture of PbI2 (PI) and methylammonium iodide (CH3NH3I, MAI) in N,N-dimethylformamide (DMF) into a precursor solution containing a polymeric strip of a plumbate(II) dimer [(MA+)2(PbI3–)2·(DMF)2]m, which then produces a perovskite film with loss of DMF upon spin-coating and heating of the substrate. We report here that the PI-to-PV conversion and the PV crystal growth to micrometer size can be accelerated by a small amount of zwitterionic sulfamic acid (NH3SO3, SA) and that sulfamic acid facilitates electron transfer to a neighboring electron-accepting layer in an SC device. As a result, an SC device on indium tin oxide (ITO)/glass made of a 320 nm thick PV film using 0.7 wt % SA showed a higher short-circuit current, open-circuit voltage, and fill factor and hence a 22.5% higher power conversion efficiency of 16.02% compared with the device made without SA. The power conversion efficiency value was reproducible (±0.3% for 25 devices), and the device showed very small hysteresis. The device without any encapsulation showed a respectable longevity on a shelf under nitrogen under ambient light. A flexible device similarly fabricated on ITO/poly(ethylene naphthalate) showed an efficiency of 12.4%.
Co-reporter:Tomoya Nakamura;Dr. Shunsuke Furukawa; Eiichi Nakamura
Chemistry – An Asian Journal 2016 Volume 11( Issue 14) pp:2016-2020
Publication Date(Web):
DOI:10.1002/asia.201600673
Abstract
Benzodipyrrole-based donor–acceptor boron complexes were designed and synthesized as near-infrared-absorbing materials. The electron-rich organic framework combined with the Lewis acidic boron co-ordination enabled us to tune the LUMO energy level and the HOMO–LUMO gap (i.e.,the absorption wavelength) by changing the organic acceptor units, the number of boron atoms, and the substituents on the boron atoms.
Co-reporter:Ricardo M. Gorgoll; Takuya Tsubota; Koji Harano
Journal of the American Chemical Society 2015 Volume 137(Issue 24) pp:7568-7571
Publication Date(Web):June 4, 2015
DOI:10.1021/jacs.5b03632
Adsorption of gold nanoparticles (NPs) on a hydrophobic fullerene bilayer vesicle ca. 30 nm in diameter occurs through cooperation of vesicle/NP and NP/NP interactions to produce a NP–vesicle hybrid whose surface is uniformly covered with the NPs separated from each other by a few nm. The vesicle coverage by NPs makes the NP–vesicle hybrid unusually stable to withstand high temperature, chromatographic purification, and high salt concentration—conditions too harsh for ordinary self-assembled vesicles, such as lipid vesicles, to survive. The hybrid serves as a platform of chemical reactions; for example, gold-catalyzed reduction of an aromatic nitro group and deposition of gold atoms for in situ growth of the NPs from 3.5 to 7.2 nm in diameter. The robust vesicle structure can be destroyed by the heat produced in interparticle plasmon coupling absorption of a 532 nm laser irradiation.
Co-reporter:Rui Shang; Laurean Ilies
Journal of the American Chemical Society 2015 Volume 137(Issue 24) pp:7660-7663
Publication Date(Web):June 10, 2015
DOI:10.1021/jacs.5b04818
Conversion of a C(sp2)–H or C(sp3)–H bond to the corresponding C–Me bond can be achieved by using AlMe3 or its air-stable diamine complex in the presence of catalytic amounts of an inorganic iron(III) salt and a diphosphine along with 2,3-dichlorobutane as a stoichiometric oxidant. The reaction is applicable to a variety of amide substrates bearing a picolinoyl or 8-aminoquinolyl directing group, enabling methylation of a variety of (hetero)aryl, alkenyl, and alkyl amides. The use of the mild aluminum reagent prevents undesired reduction of iron and allows the reaction to proceed with catalyst turnover numbers as high as 6500.
Co-reporter:Paula Mayorga Burrezo; Xiaozhang Zhu; Shou-Fei Zhu; Qifan Yan; Juan T. López Navarrete; Hayato Tsuji; Eiichi Nakamura;Juan Casado
Journal of the American Chemical Society 2015 Volume 137(Issue 11) pp:3834-3843
Publication Date(Web):March 2, 2015
DOI:10.1021/ja5125463
We have used Raman spectroscopy to study the molecular and electronic structures of the radical cations and dications of carbon-bridged oligo(para-phenylenevinylene)s (COPVn, n = 1–6) possessing consecutive fused pentagons and hexagons, up to 19, along with COPV derivatives having electron-donating and -withdrawing groups. This study was made possible by the outstanding stability of the charged states of COPVs. We could untangle the effects of π-conjugation in the planar structure on the Raman frequency by distinguishing it from other structural effects, such as strain in the vinylene groups shared by the two pentagons. The analyses showed that the radical cations have benzo-quinoidal structures confined in the center of the molecule, as well as benzo-aromatic rings at the terminal sites. In contrast, dications of COPVn longer than n = 3 exhibit a biradicaloid character because of the recovery of aromaticity in the central rings and quinoidal rings at the terminal positions. These biradicaloids favor a singlet nature in their ground electronic states because of the double spin polarization. The introduction of electron-donating and -withdrawing groups on the termini of a COPV core affords, upon oxidation or reduction, a fully delocalized class III mixed valence system because of the high degree of conjugation of the COPV platform, which favors extensive charge delocalization.
Co-reporter:Ricardo M. Gorgoll; Emrah Yücelen; Akihito Kumamoto; Naoya Shibata; Koji Harano
Journal of the American Chemical Society 2015 Volume 137(Issue 10) pp:3474-3477
Publication Date(Web):March 3, 2015
DOI:10.1021/jacs.5b00511
Atomic resolution transmission electron microscopic observations at different electron acceleration voltages enabled us to observe visually the energy relaxation process of one conformer into another via rotation of various parts of the molecule. Cross-correlation analysis of sequential transmission electron microscopy (TEM) images or of the difference between experimental and simulated TEM images has been utilized for investigation of the conformational mobility and for structure identification of conformers.
Co-reporter:Yonggang Zhen; Hideyuki Tanaka; Koji Harano; Satoshi Okada; Yutaka Matsuo
Journal of the American Chemical Society 2015 Volume 137(Issue 6) pp:2247-2252
Publication Date(Web):January 27, 2015
DOI:10.1021/ja513045a
A solid solution of a 75:25 mixture of tetrabenzoporphyrin (BP) and dichloroacenaphtho[q]tribenzo[b,g,l]porphyrin (CABP) forms when they are generated in a matrix of (dimethyl(o-anisyl)silylmethyl)(dimethylphenylsilylmethyl)[60]fullerene. This solid solution provides structural and optoelectronic properties entirely different from those of either pristine compounds or a mixture at other blending ratios. The use of this BP:CABP solid solution for organic solar cell (OSC) devices resulted in a power conversion efficiency (PCE) value higher by 16 and 300% than the PCE values obtained for the devices using the single donor BP and CABP, respectively, in a planar heterojunction architecture. This increase originates largely from the increase in short circuit current density, and hence by enhanced charge carrier separation at the donor/acceptor interface, which was probably caused by suitable energy level for the solid solution state, where electronic coupling between the two porphyrins occurred. The results suggest that physical and chemical modulation in solid solution is beneficial as an operationally simple method to enhance OSC performance.
Co-reporter:Yunlong Guo; Kazutaka Shoyama; Wataru Sato; Yutaka Matsuo; Kento Inoue; Koji Harano; Chao Liu; Hideyuki Tanaka
Journal of the American Chemical Society 2015 Volume 137(Issue 50) pp:15907-15914
Publication Date(Web):November 29, 2015
DOI:10.1021/jacs.5b10599
Despite tremendous progress in optoelectronic devices using lead perovskite (CH3NH3+PbI3–), there has been a paucity of mechanistic information on how photoactive micron-sized crystals of lead perovskite grow from a mixture of a layered crystal of lead(II) iodide and methylammonium iodide mediated by a polar solvent, DMSO or DMF. We report here that the whole process of the lead perovskite synthesis consists of a series of equilibria driven by reversible solvent participation involving a polymeric strip of plumbate(II) oligomer as a key intermediate. A significant finding includes quick decomposition of perovskite crystal upon exposure to DMSO or DMF at room temperature, where the solvent molecules act as a base to remove acidic ammonium iodide from the perovskite crystal. This observation accounts for the difficulty in controlling perovskite solar cell fabrication. Overall, the polar solvent is indispensible first to degrade a 2-D sheet of crystals of lead(II) iodide into 1-D fibrous intermediates and then to promote Oswald ripening of perovskite crystals. The detailed chemical information provided here will help to rationalize the photovoltaic device studies that have so far remained empirical and to open a new venue to a developing field of microscale lead perovskite devices, as illustrated by fabrication of photovoltaic devices and photodetectors.
Co-reporter:Yunlong Guo; Chao Liu; Hideyuki Tanaka
The Journal of Physical Chemistry Letters 2015 Volume 6(Issue 3) pp:535-539
Publication Date(Web):January 22, 2015
DOI:10.1021/jz502717g
Stable perovskite CH3NH3PbI3–xClx for a photodetector was prepared through spin-coating of a fluorous polymer as a light protection layer. The best responsivity of photodetector was 14.5 A/W to white light and 7.85 A/W for solar-blind UV light (λ = 254 nm). The response time was in the submicrosecond range. The fluorous polymer coating increases the lifetime of the devices to almost 100 days.
Co-reporter:Rui Shang ; Laurean Ilies ; Sobi Asako
Journal of the American Chemical Society 2014 Volume 136(Issue 41) pp:14349-14352
Publication Date(Web):September 30, 2014
DOI:10.1021/ja5070763
We report here that an iron-catalyzed directed C–H functionalization reaction allows the coupling of a variety of aromatic, heteroaromatic, and olefinic substrates with alkenyl and aryl boron compounds under mild oxidative conditions. We rationalize these results by the involvement of an organoiron(III) reactive intermediate that is responsible for the C–H bond-activation process. A zinc salt is crucial to promote the transfer of the organic group from the boron atom to the iron(III) atom.
Co-reporter:Laurean Ilies ; Tatsuaki Matsubara ; Saki Ichikawa ; Sobi Asako
Journal of the American Chemical Society 2014 Volume 136(Issue 38) pp:13126-13129
Publication Date(Web):July 17, 2014
DOI:10.1021/ja5066015
Alkenes, arenes, and heteroarenes possessing an 8-quinolylamide group as the directing group are alkylated with primary and secondary alkyl tosylates, mesylate, and halides in the presence of Fe(acac)3/diphosphine as a catalyst and ArZnBr as a base. The reaction proceeds stereospecifically for alkene substrates and takes place without loss of regiochemical integrity of the starting secondary tosylate, but with loss of the stereochemistry of the chiral center.
Co-reporter:Yoko Abe ; Hideyuki Tanaka ; Yunlong Guo ; Yutaka Matsuo
Journal of the American Chemical Society 2014 Volume 136(Issue 9) pp:3366-3369
Publication Date(Web):February 18, 2014
DOI:10.1021/ja500340f
A singly bonded fullerene dimer [C60R]2 in the solid state thermally generates a pair of fullerene radicals C60R• that dissociate reversibly and irreversibly upon heating and cooling of the solid. The temperature dependence of the electron mobility of the solid shows striking nonlinearity, caused by the dissociation of a strongly interacting radical pair into two free radicals, which interact with the neighboring fullerene molecules to increase the mobility 10 times to a value of 1.5 × 10–3 cm2 V–1 s–1. The nonlinearity is due to the plastic crystalline nature of fullerene crystals.
Co-reporter:Yunlong Guo, Chao Liu, Kento Inoue, Koji Harano, Hideyuki Tanaka and Eiichi Nakamura
Journal of Materials Chemistry A 2014 vol. 2(Issue 34) pp:13827-13830
Publication Date(Web):20 Jun 2014
DOI:10.1039/C4TA02976C
Significant enhancement in the power conversion efficiency of an organic–inorganic hybrid solar cell was achieved by the use of suitably doped poly(3-hexylthiophene-2,5-diyl) (P3HT) spin coated on a 99.5% void-free perovskite layer prepared on a TiOx electron-transporting layer. The 9.2% device efficiency with pristine P3HT was increased to 12.4%.
Co-reporter:Hayato Tsuji, Chikahiko Mitsui and Eiichi Nakamura
Chemical Communications 2014 vol. 50(Issue 94) pp:14870-14872
Publication Date(Web):15 Sep 2014
DOI:10.1039/C4CC05108D
The hydrogen/deuterium primary kinetic isotope effect provides useful information about the degradation mechanism of OLED host materials. Thus, replacement of labile C–H bonds in the host with C–D bonds increases the device lifetime by a factor of five without loss of efficiency, and replacement with C–C bonds by a factor of 22.5.
Co-reporter:Sobi Asako;Jakob Norinder;Laurean Ilies;Naohiko Yoshikai
Advanced Synthesis & Catalysis 2014 Volume 356( Issue 7) pp:1481-1485
Publication Date(Web):
DOI:10.1002/adsc.201400063
Co-reporter:Yutaka Matsuo, Yoichiro Kuninobu, Shingo Ito, Masaya Sawamura and Eiichi Nakamura
Dalton Transactions 2014 vol. 43(Issue 20) pp:7407-7412
Publication Date(Web):24 Sep 2013
DOI:10.1039/C3DT52002A
Acylated buckyferrocene and ruthenocene, Fe(η5-C60Me5)(η5-C5H4COR) (R = Me, Ph, and CHCHPh) and Ru(η5-C60Me5)(η5-C5H4COR) (R = Me and Ph), were obtained by Friedel–Crafts acylation of the parent buckymetallocenes with the corresponding acid chlorides and aluminum chloride in carbon disulfide at ambient temperature. The electron withdrawing and sterically hindered nature of the acyl groups were revealed by X-ray crystallography, infrared spectroscopy and electrochemical measurements. The possibility of further derivatizing the acylated products was illustrated by the conversion of the acetyl buckyruthenocene into the corresponding hydroxy and acetoxy compounds Ru(η5-C60Me5)(η5-C5H4CH(OH)Me) and Ru(η5-C60Me5)(η5-C5H4CH(OAc)Me).
Co-reporter:Koji Harano;Satoshi Okada;Shunsuke Furukawa;Hideyuki Tanaka
Journal of Polymer Science Part B: Polymer Physics 2014 Volume 52( Issue 12) pp:833-841
Publication Date(Web):
DOI:10.1002/polb.23493
ABSTRACT
Poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) is the most popular anode buffer coated on indium tin oxide. It is thought to improve the inorganic–organic contact, but little is known about its role in organic–organic contact. This study addresses the latter issue by examining how the PEDOT:PSS layer affects the crystallization process of the neighboring layer composed of p-type organic semiconductors in an organic photovoltaic device. Low landing voltage scanning electron microscopic analysis of crystals and aggregates of two donor compounds, tetrabenzoporphyrin (BP) and poly(3-hexylthiophene) (P3HT), showed that PEDOT:PSS effectively nucleates the crystallization or aggregation of the donor material on its surface to form a uniformly thick film of polycrystalline BP or aggregated P3HT molecules. By contrast, a graphitic surface cannot induce structural order of the donor molecules on it. This result implies that pinning of the donor molecules to the acidic PEDOT:PSS surface promotes the heterogeneous nucleation at the organic–organic interface. © 2014 Wiley Periodicals, Inc. J. Polym. Sci. Part B: Polym. Phys. 2014, 52, 833–841
Co-reporter:Yutaka Matsuo;Junya Kawai;Hiroshi Inada;Takafumi Nakagawa;Hitoshi Ota;Saika Otsubo
Advanced Materials 2013 Volume 25( Issue 43) pp:6266-6269
Publication Date(Web):
DOI:10.1002/adma.201302607
Co-reporter:Sobi Asako ; Laurean Ilies
Journal of the American Chemical Society 2013 Volume 135(Issue 47) pp:17755-17757
Publication Date(Web):November 11, 2013
DOI:10.1021/ja4106368
Arenes possessing an N-(quinolin-8-yl)amide directing group are ortho-allylated with allyl phenyl ether in the presence of an iron/diphosphine catalyst and an organometallic base at 50–70 °C. The reaction proceeds via fast iron-catalyzed C–H activation, followed by reaction of the resulting iron intermediate with the allyl ether in γ-selective fashion.
Co-reporter:Tatsuaki Matsubara ; Sobi Asako ; Laurean Ilies
Journal of the American Chemical Society 2013 Volume 136(Issue 2) pp:646-649
Publication Date(Web):December 31, 2013
DOI:10.1021/ja412521k
Arenes possessing an 8-quinolinylamide group as a directing group are ortho aminated with N-chloroamines and N-benzoyloxyamines in the presence of an iron/diphosphine catalyst and an organometallic base to produce anthranilic acid derivatives in high yield. The reaction proceeds via iron-catalyzed C–H activation, followed by the reaction of the resulting iron intermediate with N-chloroamine. The choice of the directing group and diphosphine ligand is crucial for obtaining the anthranilic acid derivative with high yield and product selectivity.
Co-reporter:Koji Harano ; Shinya Takenaga ; Satoshi Okada ; Yoshiko Niimi ; Naohiko Yoshikai ; Hiroyuki Isobe ; Kazu Suenaga ; Hiromichi Kataura ; Masanori Koshino
Journal of the American Chemical Society 2013 Volume 136(Issue 1) pp:466-473
Publication Date(Web):December 17, 2013
DOI:10.1021/ja411235x
Whereas a statistical average of molecular ensembles has been the conventional source of information on molecular structures, atomic resolution movies of single organic molecules obtained by single-molecule real-time transmission electron microscopy have recently emerged as a new tool to study the time evolution of the structures of individual molecules. The present work describes a proof-of-principle study of the determination of the conformation of each C–C bond in single perfluoroalkyl fullerene molecules encapsulated in a single-walled carbon nanotube (CNT) as well as those attached to the outer surface of a carbon nanohorn (CNH). Analysis of 82 individual molecules in CNTs under a 120 kV electron beam indicated that 6% of the CF2–CF2 bonds and about 20% of the CH2–CH2 bonds in the corresponding hydrocarbon analogue are in the gauche conformation. This comparison qualitatively matches the known conformational data based on time- and molecular-average as determined for ensembles. The transmission electron microscopy images also showed that the molecules entered the CNTs predominantly in one orientation. The molecules attached on a CNH surface moved more freely and exhibited more diverse conformation than those in a CNT, suggesting the potential applicability of this method for the determination of the dynamic shape of flexible molecules and of detailed conformations. We observed little sign of any decomposition of the specimen molecules, at least up to 107 e·nm–2 (electrons/nm2) at 120 kV acceleration voltage. Decomposition of CNHs under irradiation with a 300 kV electron beam was suppressed by cooling to 77 K, suggesting that the decomposition is a chemical process. Several lines of evidence suggest that the graphitic substrate and the attached molecules are very cold.
Co-reporter:Rui Shang ; Laurean Ilies ; Arimasa Matsumoto
Journal of the American Chemical Society 2013 Volume 135(Issue 16) pp:6030-6032
Publication Date(Web):April 12, 2013
DOI:10.1021/ja402806f
A 2,2-disubstituted propionamide bearing an 8-aminoquinolinyl group as the amide moiety can be arylated at the β-methyl position with an organozinc reagent in the presence of an organic oxidant, a catalytic amount of an iron salt, and a biphosphine ligand at 50 °C. Various features of selectivity and reactivity suggest the formation of an organometallic intermediate via rate-determining C–H bond cleavage rather than a free-radical-type reaction pathway.
Co-reporter:Takahiko Ichiki, Yutaka Matsuo and Eiichi Nakamura
Chemical Communications 2013 vol. 49(Issue 3) pp:279-281
Publication Date(Web):08 Nov 2012
DOI:10.1039/C2CC36988E
A new type of acceptor–donor2 dyad system containing two magnesium porphyrin molecules and a fullerene molecule is much more stable than the magnesium porphyrin itself. When it is fabricated into a binary system using imidazole carboxylic acid as a linker to indium tin oxide, the molecule effects efficient photocurrent generation that surpasses the device using the corresponding zinc porphyrin.
Co-reporter:Xiaozhang Zhu, Hayato Tsuji, Aswani Yella, Anne-Sophie Chauvin, Michael Grätzel and Eiichi Nakamura
Chemical Communications 2013 vol. 49(Issue 6) pp:582-584
Publication Date(Web):04 Dec 2012
DOI:10.1039/C2CC37124C
We demonstrate that a carbon-bridged phenylenevinylene (CPV)-linked dye serves as a novel and efficient sensitizer for dye-sensitized solar cells. The cells show IPCE values of greater than 90%, PCEs of up to 7.12%, and high open circuit voltages reaching close to 0.8 V based on the iodide/triiodide electrolyte.
Co-reporter:Koji Harano, Kosuke Minami, Eisei Noiri, Koji Okamoto and Eiichi Nakamura
Chemical Communications 2013 vol. 49(Issue 34) pp:3525-3527
Publication Date(Web):13 Mar 2013
DOI:10.1039/C3CC40752G
We prepared self-assembled vesicles comprising layers of fullerene, alkyl chains, triazole, oligo(ethylene oxide) chains, biotin and avidin molecules. High-resolution scanning electron microscopy using a superhydrophilic indium-tin oxide substrate was found to be useful for nanometer-level structural analysis of the vesicles and individual avidin molecules whose structures are difficult to analyze.
Co-reporter:Zuo Xiao, Yutaka Matsuo, Masashi Maruyama, and Eiichi Nakamura
Organic Letters 2013 Volume 15(Issue 9) pp:2176-2178
Publication Date(Web):April 23, 2013
DOI:10.1021/ol400713t
Heating of a singly bonded fullerene dimer in the presence of an alkyne forms a cyclobutene structure on only one of the two fullerene moieties, through a stereo- and regioselective [2 + 2] cycloaddition. Experimental and theoretical data suggest that the reaction is triggered by cleavage of the interfullerene C–C bond and formation of a monomeric fullerene radical.
Co-reporter:Masaki Sekine, Laurean Ilies, and Eiichi Nakamura
Organic Letters 2013 Volume 15(Issue 3) pp:714-717
Publication Date(Web):January 22, 2013
DOI:10.1021/ol400056z
An aryl Grignard reagent in the presence of mesityl iodide converts an allylic C–H bond of a cycloalkene or an allylbenzene derivative into a C–C bond in the presence of a catalytic amount of Fe(acac)3 and a diphosphine ligand at 0 °C. The stereo- and regioselectivity of the reaction, together with deuterium labeling experiments, suggest that C–H bond activation is the slow step in the catalytic cycle preceding the formation of an allyliron intermediate.
Co-reporter:Koji Harano, Ricardo Mizoguchi Gorgoll and Eiichi Nakamura
Chemical Communications 2013 vol. 49(Issue 69) pp:7629-7631
Publication Date(Web):27 Jun 2013
DOI:10.1039/C3CC44510K
Upon dissolution of R5C60−K+ in water, a robust spherical vesicle forms that binds aromatic molecules primarily in the interior of the fullerene bilayer, as illustrated by the complete quenching of the fluorescence of an aromatic fluorescent dye bound in the bilayer.
Co-reporter: Eiichi Nakamura
Angewandte Chemie 2013 Volume 125( Issue 1) pp:248-266
Publication Date(Web):
DOI:10.1002/ange.201205693
Abstract
“The truth is, the Science of Nature has been already too long made only a work of the Brain and the Fancy: It is now high time that it should return to the plainness and soundness of Observations on material and obvious things,” das erklärte der stolze Robert Hooke in seinem Bildband von Mikroskop- und Teleskopbildern “Micrographia” im Jahre 1665. In der Chemie ist Hookes Äußerung heute noch gültig, wo ein erheblicher Arbeitsanteil notwendigerweise im Gehirn und durch Einbildungskraft stattfindet. Die Einzelmolekül-Echtzeit-Transmissionselektronenmikroskopie (SMRT-TEM) als bildgebendes Verfahren mit atomarer Auflösung ermöglicht es uns jetzt, durch einfaches Zusehen mehr über Moleküle zu lernen. Wie bei jedem Traum, der wahr wurde, erforderte die Etablierung der neuen Analysemethode das Überdenken allgemein akzeptierter Meinungen in der Wissenschaft, und bietet nun neue Forschungsmöglichkeiten, die mit konventionellen Methoden nicht verfügbar sind. Mit ihrem Leistungsvermögen, die Bewegungen und Reaktionen einzelner Moleküle und Molekülcluster zu visualisieren, wird sich die SMRT-TEM zum unverzichtbaren Werkzeug in den Molekularwissenschaften, der Entwicklung von natürlichen und synthetischen Stoffen sowie der wissenschaftlichen Ausbildung entwickeln.
Co-reporter: Eiichi Nakamura
Angewandte Chemie International Edition 2013 Volume 52( Issue 1) pp:236-252
Publication Date(Web):
DOI:10.1002/anie.201205693
Abstract
“The truth is, the Science of Nature has been already too long made only a work of the Brain and the Fancy: It is now high time that it should return to the plainness and soundness of Observations on material and obvious things,” proudly declared Robert Hooke in his highly successful picture book of microscopic and telescopic images, “Micrographia” in 1665. Hooke’s statement has remained true in chemistry, where a considerable work of the brain and the fancy is still necessary. Single-molecule, real-time transmission electron microscope (SMRT-TEM) imaging at an atomic resolution now allows us to learn about molecules simply by watching movies of them. Like any dream come true, the new analytical technique challenged the old common sense of the communities, and offers new research opportunities that are unavailable by conventional methods. With its capacity to visualize the motions and the reactions of individual molecules and molecular clusters, the SMRT-TEM technique will become an indispensable tool in molecular science and the engineering of natural and synthetic substances, as well as in science education.
Co-reporter:Naohiko Yoshikai and Eiichi Nakamura
Chemical Reviews 2012 Volume 112(Issue 4) pp:2339
Publication Date(Web):November 23, 2011
DOI:10.1021/cr200241f
Co-reporter:Laurean Ilies ; Takumi Yoshida
Journal of the American Chemical Society 2012 Volume 134(Issue 41) pp:16951-16954
Publication Date(Web):October 3, 2012
DOI:10.1021/ja307631v
Diarylalkynes are chemo- and stereoselectively hydromagnesiated in high yields at room temperature with an iron species generated in situ from FeCl2and EtMgBr. Functional groups such as bromide, iodide, amine, phenoxide, and alkene are well tolerated. Under similar conditions, diynes are chemo-, regio-, and stereoselectively hydromagnesiated. The resulting alkenylmagnesium compounds are a platform for further functionalization as a one-pot reaction.
Co-reporter:Chikahiko Mitsui ; Junshi Soeda ; Kazumoto Miwa ; Hayato Tsuji ; Jun Takeya
Journal of the American Chemical Society 2012 Volume 134(Issue 12) pp:5448-5451
Publication Date(Web):March 14, 2012
DOI:10.1021/ja2120635
We here report naphtho[2,1-b:6,5-b′]difuran derivatives as new p-type semiconductors that achieve hole mobilities of up to 3.6 cm2 V–1 s–1 along with high Ion/Ioff ratios in solution-processed single-crystal organic field-effect transistors. These features originate from the dense crystal packing and the resulting large intermolecular π-orbital overlap as well as from the small reorganization energy, all of which originate from the small radius of an oxygen atom.
Co-reporter:Xiaozhang Zhu ; Hayato Tsuji ; Juan T. López Navarrete ; Juan Casado
Journal of the American Chemical Society 2012 Volume 134(Issue 46) pp:19254-19259
Publication Date(Web):October 29, 2012
DOI:10.1021/ja309318s
The high responsiveness of π-conjugated materials to external stimuli, such as electrons and photons, accounts for both their utility in optoelectronic applications and their chemical instability. Extensive studies on heteroatom-stabilized π-conjugated systems notwithstanding, it is still difficult to combine high performance and stability. We report here that carbon-bridged oligo(p-phenylenevinylene)s (COPV-n) are not only more responsive to doping and photoexcitation but also more stable than the conventional p-phenylenevinylenes and poly(3-hexylthiophene), surviving photolysis very well in air, suggesting that they could serve as building blocks for optoelectronic applications. Activation of the ground state by installation of bond angle strain toward the doped or photoexcited state and the flat, rigid, and hindered structure endows COPVs with stimuli-responsiveness and stability without recourse to heteroatoms. For example, COPV-6 can be doped with an extremely small reorganization energy and form a bipolaron delocalized over the entire π-conjugated system. Applications to bulk and molecular optoelectronic devices are foreseen.
Co-reporter:Takeshi Fujita, Yutaka Matsuo, and Eiichi Nakamura
Chemistry of Materials 2012 Volume 24(Issue 20) pp:3972
Publication Date(Web):September 14, 2012
DOI:10.1021/cm3024296
Dianions of deca(phenyl)[60]fullerene–bis(cyclopentadienyl ruthenium) complex, (C60Ph10)(RuCp)2 (1a), and dimethylated deca(phenyl)[60]fullerene, C60Ph10Me2 (1b), reacted with benzyl bromide to produce [C60Ph10(CH2Ph2)2](RuCp)2 (3a and 4a) and tetradeca(organo)[60]fullerenes C60Ph10(CH2Ph2)2Me2 (3b and 4b), respectively (Compounds 3 and 4 refer to C2v and C1 symmetric compounds, respectively.). Nucleophilic addition of benzylmagnesium chloride with the C1 symmetric compounds 4a and 4b yielded [C60Ph10(CH2Ph2)3H](RuCp)2 (5a) and pentadeca(organo)[60]fullerenes C60Ph10(CH2Ph2)3Me2H (5b), respectively. Products were structurally characterized by X-ray crystallographic analysis of diruthenium complexes 3a, 4a, and 5a. These X-ray studies revealed that compounds 3, 4, and 5 have unique π-conjugated systems consisting of doubly bridged triphenylene dimer, triphenylene–benzoacenaphthylene, and triphenylene–biphenyl structures, respectively. Quantum mechanical calculations suggested that these π-conjugated systems are aromatic. Containing no metal atom, methylated derivatives 3b, 4b, and 5b exhibited green, pale yellow, and turquoise blue emissions with quantum yields of 0.066, 0.12, and 0.24, respectively. The application of these materials in organic light-emitting diodes was demonstrated.Keywords: aromaticity; fluorescence; fullerene; organic light-emitting diode; ruthenium; π-conjugated system;
Co-reporter:Zuo Xiao, Yutaka Matsuo, Iwao Soga, and Eiichi Nakamura
Chemistry of Materials 2012 Volume 24(Issue 13) pp:2572
Publication Date(Web):June 5, 2012
DOI:10.1021/cm301238n
Two new reactions for the synthesis of structurally defined 66π-electron [70]fullerene derivatives are reported. The first provides synthetic access to tetra-phenyl or [3 + 1] hybrid tetra-aryl C70 adducts via oxidation of a fullerene copper complex [Ar3C70–Cu–Ar′]− (Ar = Ph, 4-nBuC6H4; Ar′ = Ph, 4-MeOC6H4). The second provides access to alkyl fullerene ethers, C70Ar3(2-EH) via AgClO4-mediated coupling of a [70]fullerene bromide C70Ar3Br with 2-ethylhexanol (2-EH). The first reaction afforded two types of regioisomers including a 3,10,22,25-adduct (denoted type I) and a 7,10,22,25-adduct (type II). The haptotropic migration of the copper on a cuprio fullerene intermediate was suggested to be responsible for the generation of the two regioisomers. The second reaction gave only one regioisomer (type II). The eight new 66π-electron [70]fullerene derivatives synthesized are electrochemically and thermally stable, and their photoabsorption and electrochemical properties are closely related to the addition pattern. For example, the type II regioisomers have higher LUMO levels than the type I isomers. Through modification of the addends, the LUMO levels of these [70]fullerene derivatives can be raised by as much as 220 meV, that is, from −3.80 to −3.58 eV. Solution-processed p-n junction organic photovoltaic devices using five soluble compounds 5, 9, 10, 13, and 15 as the n-type semiconducting materials were fabricated. The device using compound 15 (LUMO = −3.58 eV) showed the highest open circuit voltage (Voc = 0.90 V) and a respectable PCE value of 3.33%. For Jsc and FF, type II compounds 10, 13, and 15 showed much higher values than did type I compounds 5 and 9, suggesting that the type II addition pattern on C70 may be superior to the type I pattern for efficient electron transport, likely because of better molecular packing in crystals as suggested by crystallographic data.Keywords: copper; fullerene; migration; organic solar cells; porphyrin;
Co-reporter:Sebastian Lacher, Naoki Obata, Shyh-Chyang Luo, Yutaka Matsuo, Bo Zhu, Hsiao-hua Yu, and Eiichi Nakamura
ACS Applied Materials & Interfaces 2012 Volume 4(Issue 7) pp:3396
Publication Date(Web):June 27, 2012
DOI:10.1021/am300366d
A new class of conductive polyelectrolyte films with tunable work function and hydrophobicity has been developed for the anode buffer layer in organic electronic devices. The work function of these films featuring a copolymer of ethylenedioxythiophene (EDOT), and its functionalized analogues were found to be easily tunable over a range of almost 1 eV and reach values as high as those of PEDOT:PSS. The new buffer material does not need the addition of any insulating or acidic material that might limit the film conductivity or device lifetime. Organic photovoltaic devices built with these films showed improved open-circuit voltage over those of the known PSS-free conductive EDOT-based polymers with values as high as that obtained for PEDOT:PSS. Furthermore, the surface hydrophobicity of these new copolymer films was found to be sensitive to the chemical groups attached to the polymer backbone, offering an attractive method for surface energy tuning.Keywords: conductive polymer; hole-injection layer; organic solar cell; surface energy; work function;
Co-reporter:Yutaka Matsuo, Ayako Ozu, Naoki Obata, Naoya Fukuda, Hideyuki Tanaka and Eiichi Nakamura
Chemical Communications 2012 vol. 48(Issue 32) pp:3878-3880
Publication Date(Web):24 Feb 2012
DOI:10.1039/C2CC30262D
A chemical model of deterioration of a bulk heterojunction organic solar cell containing a photooxidized product of 1,4-bis(dimethylphenylsilylmethyl)[60]fullerene suggests that molecular oxygen degrades device performance by two mechanisms.
Co-reporter:Xiaoming Zeng, Laurean Ilies, and Eiichi Nakamura
Organic Letters 2012 Volume 14(Issue 3) pp:954-956
Publication Date(Web):January 24, 2012
DOI:10.1021/ol203446t
Terminal alkynes react with aromatic sulfonyl chlorides in the presence of an iron(II) catalyst and a phosphine ligand to give (E)-β-chlorovinylsulfones with 100% regio- and stereoselectivity. Various functional groups, such as chloride, bromide, iodide, nitro, ketone, and aldehyde, are tolerated under the reaction conditions. Addition of tosyl chloride to a 1,6-enyne followed by radical 5-exo-trig cyclization gave an exocyclic alkenylsulfone.
Co-reporter:Yuki Nakamura, Naohiko Yoshikai, Laurean Ilies, and Eiichi Nakamura
Organic Letters 2012 Volume 14(Issue 13) pp:3316-3319
Publication Date(Web):June 12, 2012
DOI:10.1021/ol301195x
A new diphosphine (POP) ligand bearing an alkoxide group allows us to synthesize partially fluorinated arenes. A nickel-catalyzed cross-coupling between a polyfluoroarene and an organozinc reagent in the presence of POP selectively produces a monosubstitution product. Aryl and alkylzinc reagents smoothly take part in the reaction. It is speculated that monosubstitution is the result of accelerated product expulsion from the product/catalyst complex.
Co-reporter:Laurean Ilies, Tatsuaki Matsubara, and Eiichi Nakamura
Organic Letters 2012 Volume 14(Issue 21) pp:5570-5573
Publication Date(Web):October 25, 2012
DOI:10.1021/ol302688u
A nickel-catalyzed oxidative coupling of zinc amides with organomagnesium compounds selectively produces diarylamines under mild reaction conditions, with tolerance for chloride, bromide, hydroxyl, ester, and ketone groups. A diamine is bis-monoarylated. A bromoaniline undergoes N-arylation followed by Kumada–Tamao–Corriu coupling in one pot. The reaction may proceed via oxidatively induced reductive elimination of a nickel species.
Co-reporter:Laurean Ilies;Motoaki Kobayashi;Arimasa Matsumoto;Naohiko Yoshikai
Advanced Synthesis & Catalysis 2012 Volume 354( Issue 4) pp:593-596
Publication Date(Web):
DOI:10.1002/adsc.201100791
Abstract
2-Arylpyridines, 2-alkenylpyridine, and aromatic imines can be coupled with aryl bromides in the presence of an iron catalyst, metallic magnesium, a diamine ligand and an organic dihalide oxidant at 0 °C. The use of a 1:1 mixture of tetrahydrofuran and 1,4-dioxane is essential for this CH bond activation reaction. The reaction has wider scope of the substrate compared with the reaction using a separately prepared Grignard reagent, and proceeds with lower catalyst loading (2.5 mol%).
Co-reporter:Dr. Laurean Ilies;Eita Konno;Quan Chen;Dr. Eiichi Nakamura
Asian Journal of Organic Chemistry 2012 Volume 1( Issue 2) pp:142-145
Publication Date(Web):
DOI:10.1002/ajoc.201200042
Co-reporter:Dr. Hayato Tsuji;Yoshinori Ota;Dr. Shunsuke Furukawa;Dr. Chikahiko Mitsui;Dr. Yoshiharu Sato; Eiichi Nakamura
Asian Journal of Organic Chemistry 2012 Volume 1( Issue 1) pp:34-37
Publication Date(Web):
DOI:10.1002/ajoc.201200021
Co-reporter:Dr. Chikahiko Mitsui;Dr. Hayato Tsuji;Dr. Yoshiharu Sato;Dr. Eiichi Nakamura
Chemistry – An Asian Journal 2012 Volume 7( Issue 6) pp:1443-1450
Publication Date(Web):
DOI:10.1002/asia.201200062
Abstract
We have designed an ambipolar material, 3,7-bis[4-(N-carbazolyl)-phenyl]-2,6-diphenylbenzo[1,2-b:4,5-b′]difuran (CZBDF), and synthesized it by zinc-mediated double cyclization. Its physical properties clarified that CZBDF possesses a wide-gap character, well-balanced and high hole and electron mobilities of larger than 10−3 cm2 V−1 s−1, and a high thermal stability. Using CZBDF as a host material for heterojunction OLED devices, a full range of visible emission was obtained. Notably, CZBDF also enabled us to fabricate RGB-emitting homojunction OLEDs, with performances comparable or superior to the heterojunction devices composed of several materials.
Co-reporter:Xiaoming Zeng ; Laurean Ilies
Journal of the American Chemical Society 2011 Volume 133(Issue 44) pp:17638-17640
Publication Date(Web):October 11, 2011
DOI:10.1021/ja209300c
A variety of polysubstituted 1H-indenes can be prepared through the copper-catalyzed arylative cyclization of simple arylalkynes with commercially available aromatic sulfonyl chlorides that function as an aryl group donor. The reaction tolerates a broad range of functional groups, including bromide and iodide, nitrile, ketone, and nitro groups. The reaction allowed the synthesis of polycyclic aromatic hydrocarbons, such as a bis(indene), indacene, and fused polyarene derivatives, some of them showing strong fluorescence in solution and the solid state.
Co-reporter:Sebastian Lacher ; Yutaka Matsuo
Journal of the American Chemical Society 2011 Volume 133(Issue 42) pp:16997-17004
Publication Date(Web):September 16, 2011
DOI:10.1021/ja2067675
The surface properties of inorganic substrates can be altered by coating with organic molecules, which may result in the improvement of the properties suitable for electronic or biological applications. This article reports a systematic experimental study on the influence of the molecular and supramolecular properties of umbrella-shaped penta(organo)[60]fullerene derivatives, and on the work function and the water contact angle of indium–tin oxide (ITO) and gold surfaces. We could relate these macroscopic characteristics to single-molecular level properties, such as ionization potential and molecular dipole. The results led us to conclude that the formation of a SAM of a polar compound generates an electronic field through intermolecular interaction of the molecular charges, and this field makes the overall dipole of the SAM much smaller than the one expected from the simple sum of the dipoles of all molecules in the SAM. This effect, which was called depolarization and previously discussed theoretically, is now quantitatively probed by experiments. The important physical properties in surface science such as work function, ionization potential, and water contact angles have been mutually correlated at the level of molecular structures and molecular orientations on the substrate surface. We also found that the SAMs on ITO and gold operate under the same principle except that the “push-back” effect operates specifically for gold. The study also illustrates the ability of the photoelectron yield spectroscopy technique to rapidly measure the work function of a SAM-covered substrate and the ionization potential value of a molecule on the surface.
Co-reporter:Xiaozhang Zhu ; Hayato Tsuji ; Koji Nakabayashi ; Shin-ichi Ohkoshi
Journal of the American Chemical Society 2011 Volume 133(Issue 41) pp:16342-16345
Publication Date(Web):September 20, 2011
DOI:10.1021/ja206060n
A heptacyclic carbocycle possessing three p-quinodimethane units conjugated in one plane has been synthesized and shown to exhibit distinct biradical characteristics. The molecule has a HOMO/LUMO band gap of ca. 1 eV and a S0–T1 energy gap of 2.12 kcal/mol, and it absorbs and emits near-IR light at room temperature. It is air-stable under ambient light for several months and thermally stable up to 160 °C under nitrogen, and it undergoes reversible two-electron oxidation and reduction. The synthetic approach is such that a smaller and larger oligo-p-quinodimethane can be synthesized.
Co-reporter:Eiichi Nakamura ; Masanori Koshino ; Takeshi Saito ; Yoshiko Niimi ; Kazu Suenaga ;Yutaka Matsuo
Journal of the American Chemical Society 2011 Volume 133(Issue 36) pp:14151-14153
Publication Date(Web):August 22, 2011
DOI:10.1021/ja203225n
Heating a bulk sample of [60]fullerene complexes, (η5-C5H5)MC60R5 (M = Fe, Ru, R = Me, Ph), produces small hydrocarbons because of coupling of R and C5H5 via C–C and C–H bond activation. Upon observation by transmission electron microscopy, these complexes, encapsulated in single-walled carbon nanotubes, underwent C–C bond reorganization reactions to form new C–C bond networks, including a structure reminiscent of [70]fullerene. Quantitative comparison of the electron dose required to effect the C–C bond reorganization of fullerenes and organofullerenes in the presence of a single atom of Ru, Fe, or Ln and in the the absence of metal atoms indicated high catalytic activity of Ru and Fe atoms, as opposed to no catalytic activity of Ln. Organic molecules such as hydrocarbons and amides as well as pristine [60]fullerene maintain their structural integrity upon irradiation by ca. 100 times higher electron dose compared to the Ru and Fe organometallics. The results not only represent a rare example of direct observation of a single-metal catalysis but also have implications for the use of single metal atom catalysis in Group 8 metal heterogeneous catalysis.
Co-reporter:Yutaka Matsuo ; Takahiko Ichiki
Journal of the American Chemical Society 2011 Volume 133(Issue 25) pp:9932-9937
Publication Date(Web):May 23, 2011
DOI:10.1021/ja203224d
We describe a photoswitch fabricated on indium tin oxide (ITO) as a self-assembled monolayer (SAM) of two fullerene molecules, a purely organic [60]fullerene that generates an anodic current and a [70]fullerene doped with a single iron atom. This device generates a bidirectional photocurrent upon irradiation at 340 and 490 nm. The new [70]fullerene iron complex bearing three rigid carboxylic acid legs, Fe[C70(C6H4C6H4COOH)3]Cp, generates only a cathodic current upon photoexcitation between 350 and 700 nm, whereas the organic [60]fullerene absorbs at wavelengths shorter than 500 nm. The quantum efficiency of the photocurrent generation by the mixed SAM is comparable to that of a single-component SAM, indicating that the individual diode molecules on ITO generate photocurrents independently with little cross talk.
Co-reporter:Ying Zhang ; Yutaka Matsuo ; Chang-Zhi Li ; Hideyuki Tanaka
Journal of the American Chemical Society 2011 Volume 133(Issue 21) pp:8086-8089
Publication Date(Web):May 2, 2011
DOI:10.1021/ja201267t
1,2-Dihydromethano[60]fullerene and its congeners have attracted much interest, but they have been synthesized only in very low yields because of several insurmountable problems. A new three-stage synthesis involving addition of a silylmethylmagnesium chloride to [60]- and [70]fullerene and oxidation of the anionic intermediate with CuCl2 afforded the methano[60]- and methano[70]fullerenes in 90% and 70% overall yield, respectively. The reaction with 1,4-diorgano[60]fullerene also proceeded smoothly to give a diastereomerically pure 56-π-electron fullerene that has a higher LUMO level than the parent fullerene and gave a higher open-circuit voltage and better power conversion efficiency when fabricated into an organic photovoltaic device.
Co-reporter:Laurean Ilies ; Sobi Asako
Journal of the American Chemical Society 2011 Volume 133(Issue 20) pp:7672-7675
Publication Date(Web):April 27, 2011
DOI:10.1021/ja2017202
The reaction of an aryl Grignard reagent with a cyclic or acyclic olefin possessing a directing group such as pyridine or imine results in the stereospecific substitution of the olefinic C–H bond syn to the directing group. The reaction takes place smoothly and without isomerization of the product olefin in the presence of a mild oxidant (1,2-dichloro-2-methylpropane) and an aromatic cosolvent. Several lines of evidence suggest that the reaction proceeds via iron-catalyzed olefinic C–H bond activation rather than an oxidative Mizoroki–Heck-type reaction.
Co-reporter:Arimasa Matsumoto ; Laurean Ilies
Journal of the American Chemical Society 2011 Volume 133(Issue 17) pp:6557-6559
Publication Date(Web):April 7, 2011
DOI:10.1021/ja201931e
The [4 + 2] benzannulation reaction of internal or terminal alkynes with 2-biaryl, 2-heteroarylphenyl, or 2-alkenylphenyl Grignard reagents in the presence of Fe(acac)3, 4,4′-di-tert-butyl-2,2′-bipyridyl, and 1,2-dichloro-2-methylpropane takes place at room temperature in 1 h to give 9-substituted or 9,10-disubstituted phenanthrenes and congeners in moderate to excellent yields. The reaction tolerates sensitive functional groups such as bromide and olefin. When applied to a 1,3-diyne, the annulation reaction takes place on both acetylenic moieties to give a bisphenanthrene derivative.
Co-reporter:Tatsuya Homma ; Koji Harano ; Hiroyuki Isobe
Journal of the American Chemical Society 2011 Volume 133(Issue 16) pp:6364-6370
Publication Date(Web):April 1, 2011
DOI:10.1021/ja200498g
Twenty potassium complexes of penta-[(4-substituted)phenyl][60]fullerene anions were synthesized and examined for their ability to form bilayer vesicles in water. The 4-substituents include alkyl groups ranging from methyl to icosanyl groups and perfluoromethyl, perfluorobutyl, and perfluorooctyl groups. The overall structure of the amphiphiles can be described as a nonpolar/polar/nonpolar (n−p−n′) motif as opposed to the usual polar/nonpolar motif of lipid amphiphiles. Despite the hydrophobicity of the fullerene moiety (n-part) and alkyl/perfluoroalkyl chains (n′-part), all compounds except for the one with perfluoromethyl groups were soluble in water because of the centrally located fullerene cyclopentadienide (p-part) and spontaneously formed a vesicle of 25- to 60-nm diameter with a narrow unimodal size distribution. The vesicles are stable upon heating to 90 °C or standing over one year in air, as well as on a solid substrate in air or in vacuum, maintaining their spherical form. The vesicle membrane consists of an interdigitated bilayer of the amphiphile molecules, in which the fullerene n-part is inside and the n′-side is exposed to water. These vesicles, in particular the one bearing icosanyl chains, exhibit the smallest water permeability coefficient ever found for a self-assembled membrane in water.
Co-reporter:Laurean Ilies ; Quan Chen ; Xiaoming Zeng
Journal of the American Chemical Society 2011 Volume 133(Issue 14) pp:5221-5223
Publication Date(Web):March 23, 2011
DOI:10.1021/ja200645w
Insertion of 1-alkene, 2-alkene, and styrene into the ortho C−H bond of benzamide in the presence of an inexpensive cobalt catalyst, DMPU as a crucial ligand, and cyclohexylmagnesium chloride proceeds smoothly at 25 °C to selectively give the ortho-alkylated product. Notable features of this reaction include the structural variety of the alkene and the amide substrate and the tolerance of functional groups such as halide, olefin, ester, and amide groups.
Co-reporter:Quan Chen, Laurean Ilies, Naohiko Yoshikai, and Eiichi Nakamura
Organic Letters 2011 Volume 13(Issue 12) pp:3232-3234
Publication Date(Web):May 24, 2011
DOI:10.1021/ol2011264
Aromatic carboxamides and 2-phenylpyridine derivatives can be ortho-alkylated with Grignard reagents in the presence of a cobalt catalyst and DMPU as a ligand. The reaction proceeds smoothly at room temperature, using air as the sole oxidant. The dialkylated product is selectively obtained when N-methylcarboxamide is employed as a substrate, whereas N-phenyl- or N-isopropylcarboxamide preferentially gives the monoalkylated product.
Co-reporter:Pirmin A. Ulmann, Hideyuki Tanaka, Yutaka Matsuo, Zuo Xiao, Iwao Soga and Eiichi Nakamura
Physical Chemistry Chemical Physics 2011 vol. 13(Issue 47) pp:21045-21049
Publication Date(Web):21 Oct 2011
DOI:10.1039/C1CP22886B
A [70]fullerene–benzodifuranone acceptor dyad synthesized by a Ag+-mediated coupling reaction was used to construct a thin-film organic solar cell. The fullerene and the benzodifuranone dye in the dyad have close-lying LUMO levels in the range of 3.7–3.9 eV, so that energy transfer from the dye to the fullerene can take place. A p–n heterojunction photovoltaic device consisting of a tetrabenzoporphyrin and a [70]fullerene–benzodifuranone dyad showed a weak but discernible contribution from light absorption of the dyad to the photocurrent under both a positive and a negative effective bias. These results indicate that the benzodifuranone moiety attached to the acceptor contributes to light-harvesting by energy transfer.
Co-reporter:Yutaka Matsuo, Ying Zhang, Iwao Soga, Yoshiharu Sato, Eiichi Nakamura
Tetrahedron Letters 2011 Volume 52(Issue 17) pp:2240-2242
Publication Date(Web):27 April 2011
DOI:10.1016/j.tetlet.2011.01.031
An AlCl3-mediated Friedel–Crafts reaction of arenes with C60 affords two-fold hydroarylated compounds, C60Ar2H2, which upon deprotonation with tBuOK and oxidation with CuBr·SMe2 yield 1,4-diaryl[60]fullerenes, C60Ar2 (Ar = Ph, 4-Me-C6H4, 3,4-Me2-C6H3, and 4-Ph-C6H4) in good yield. A solution-processed, thin-film organic photovoltaic device using C60(4-PhC6H4)2 as electron acceptor material showed a 2.3% power conversion efficiency.
Co-reporter:Chang-Zhi Li, Yutaka Matsuo, Eiichi Nakamura
Tetrahedron 2011 67(51) pp: 9944-9949
Publication Date(Web):
DOI:10.1016/j.tet.2011.09.125
Co-reporter:Dr. Naohiko Yoshikai;Sobi Asako;Takeshi Yamakawa;Dr. Laurean Ilies;Dr. Eiichi Nakamura
Chemistry – An Asian Journal 2011 Volume 6( Issue 11) pp:3059-3065
Publication Date(Web):
DOI:10.1002/asia.201100470
Abstract
Direct arylation of the ortho-CH bond of an aryl pyridine or an aryl imine with an aryl Grignard reagent has been achieved by using an iron-diamine catalyst and a dichloroalkane as an oxidant in a short reaction time (e.g., 5 min) under mild conditions (0 °C). The use of an aromatic co-solvent, such as chlorobenzene and benzene, and slow addition of the Grignard reagent are essential for the high efficiency of the reaction. The present arylation reaction has distinct merits over the previously developed reaction that used an arylzinc reagent, such as its reaction rate and atom economy. Selective CH bond activation occurs in the presence of a leaving group, such as a tosyloxy, chloro, and bromo group. Studies on a stoichiometric reaction and kinetic isotope effects shed light on the reaction intermediate and the CH bond-activation step.
Co-reporter:Dr. Chikahiko Mitsui;Dr. Hideyuki Tanaka;Dr. Hayato Tsuji;Dr. Eiichi Nakamura
Chemistry – An Asian Journal 2011 Volume 6( Issue 9) pp:2296-2300
Publication Date(Web):
DOI:10.1002/asia.201100326
Co-reporter:Dr. Hayato Tsuji;Yuki Yokoi;Dr. Yoshiharu Sato;Dr. Hideyuki Tanaka;Dr. Eiichi Nakamura
Chemistry – An Asian Journal 2011 Volume 6( Issue 8) pp:2005-2008
Publication Date(Web):
DOI:10.1002/asia.201100234
Co-reporter:Dr. Eiichi Nakamura
Chemistry – An Asian Journal 2011 Volume 6( Issue 7) pp:1659-1663
Publication Date(Web):
DOI:10.1002/asia.201000899
Co-reporter:Quan Chen ; Laurean Ilies
Journal of the American Chemical Society 2010 Volume 133(Issue 3) pp:428-429
Publication Date(Web):December 15, 2010
DOI:10.1021/ja1099853
Coupling of an alkyl chloride with a secondary benzamide derivative at the ortho-position can be achieved in good to excellent yield in the presence of a cobalt catalyst and cyclohexylmagnesium chloride in diethyl ether at room temperature. Cyclohexylmagnesium chloride formally acts to remove hydrogen atoms from the amide nitrogen and from the ortho-position and to generate the active cobalt species.
Co-reporter:Yutaka Matsuo ; Takahiko Ichiki ; Shankara Gayathri Radhakrishnan ; Dirk M. Guldi
Journal of the American Chemical Society 2010 Volume 132(Issue 18) pp:6342-6348
Publication Date(Web):April 16, 2010
DOI:10.1021/ja909970h
A pentapod deca(aryl)[60]fullerene, C60(C6H4CO2H)5(C6H4Fc)5Me2 (4; Fc = ferrocenyl), bearing five carboxylic acid and five ferrocenyl groups was synthesized through top and bottom functionalization of [60]fullerene by means of copper-mediated penta-addition reactions. For electrochemical measurements (i.e., Eox = 0.08 V, five-electron oxidation of the ferrocenyl groups; Ered = −1.89 and −2.28 V for the fullerene part vs Fc/Fc+), we used an ester-protected compound, C60(C6H4CO2Et)5(C6H4Fc)5Me2 (2), and 4 was probed by performing femtosecond flash photolysis experiments in a variety of organic solvents. Importantly, the formation of a radical ion pair state was corroborated with lifetimes of up to 333 ps in toluene. In complementary studies, penta(carboxylic acid)−penta(ferrocenyl) compound 4 was deposited on indium−tin oxide (ITO) electrodes with a surface coverage (i.e., 0.14 nmol/cm2) that corresponded to a unique bilayer structure. Decisive for the bilayer motif is the presence of five ferrocenyl groups, which are assembled with a merry-go-round-shaped arrangement on the [60]fullerene. The novel 4/ITO photoelectrode gave rise to a cathodic photocurrent with a 12% quantum yield in the presence of methyl viologen, whereas an anodic photocurrent was generated in the presence of ascorbic acid for a C60(C6H4CO2H)5(C6H5)5Me2 (5)/ITO photoelectrode. Photophysical investigations revealed that the difference in photocurrent, that is, cathodic versus anodic photocurrents, is related to the nature of the excited state feature in 4 (i.e., charge separated state) and 5 (i.e., triplet excited state). The unique molecular architecture of 4, in combination with its remarkable donor−acceptor properties, validates the use of the pentapod deca(aryl)[60]fullerene in photoelectrochemically active molecular devices.
Co-reporter:Naohiko Yoshikai ; Adam Mieczkowski ; Arimasa Matsumoto ; Laurean Ilies
Journal of the American Chemical Society 2010 Volume 132(Issue 16) pp:5568-5569
Publication Date(Web):April 2, 2010
DOI:10.1021/ja100651t
C−C bond formation reactions that take place through organoiron species sometimes exhibit radical-like character. The reaction of N-(2-iodophenylmethyl)dialkylamine with a Grignard or diorganozinc reagent in the presence of a catalytic amount of Fe(acac)3 gives the product resulting from arylation, alkenylation, or alkylation of the sp3 C−H bond next to the amine group in good to excellent yield. Mechanistic studies including labeling experiments indicate that the reaction involves radical translocation triggered by the formation of a radical-like species by removal of the iodide group.
Co-reporter:Chang-Zhi Li ; Yutaka Matsuo
Journal of the American Chemical Society 2010 Volume 132(Issue 44) pp:15514-15515
Publication Date(Web):October 18, 2010
DOI:10.1021/ja1073933
The installation of three structural features into a fullerene molecule, a conical shape, a polar iron-ferrocene complex, and long alkyl chains, allowed dipolar molecules 1 and 2 to undergo microphase separation and to form a three-dimensional lattice in a crystalline and a thermotropic liquid crystalline phase. The key feature is a tetrameric octupole-like aggregate, in which four dipoles are arranged supramolecularly to cancel the molecular polarity, forming a sphere. In addition to this lattice formation mechanism, the molecules incorporate noteworthy features, such as redox active C60/ferrocene and luminescent cyclophenacene.
Co-reporter:Zuo Xiao ; Yutaka Matsuo
Journal of the American Chemical Society 2010 Volume 132(Issue 35) pp:12234-12236
Publication Date(Web):August 17, 2010
DOI:10.1021/ja1056399
A copper-catalyzed reaction of arylacetylene or enyne with C60Ar5Br effects a formal [4 + 2] annulation reaction to form a dihydronaphthalene ring fused to the fullerene core. The reaction involves a formal C−H bond activation and takes place by a copper-mediated radical mechanism. This reaction takes place in 60−75% overall yield from [60]fullerene and creates axial chirality in the product because of restricted rotation of the top aryl groups.
Co-reporter:Hayato Tsuji ; Yasuyuki Ueda ; Laurean Ilies
Journal of the American Chemical Society 2010 Volume 132(Issue 34) pp:11854-11855
Publication Date(Web):August 10, 2010
DOI:10.1021/ja1059119
Addition of trimethylstannyllithium to a diarylacetylene takes place exclusively in an anti-fashion to produce a lithio vinylstannane intermediate. The regioselectivity of the addition is controlled by the steric and electronic property of the acetylene and reaches up to >99:1. The two newly formed C−metal bonds can be sequentially and stereospecifically transformed into two new C−C bonds as illustrated by stereoselective synthesis of 4-hydroxytamoxifen and its regioisomer. A tetraarylethene bearing different aryl groups can be synthesized similarly and cyclized to a substituted dibenzo[g,p]chrysene derivative via a palladium-catalyzed arylation reaction.
Co-reporter:Laurean Ilies, Jun Okabe, Naohiko Yoshikai and Eiichi Nakamura
Organic Letters 2010 Volume 12(Issue 12) pp:2838-2840
Publication Date(Web):May 25, 2010
DOI:10.1021/ol1009448
Chelation-controlled arylation of olefins with organozinc or Grignard reagents proceeds in the presence of an iron catalyst, under mild conditions and typically without the need of external ligands, to afford substituted olefins in high yield and with complete regio- and stereocontrol.
Co-reporter:Tobias Gärtner, Naohiko Yoshikai, Maria Neumeier, Eiichi Nakamura and Ruth M. Gschwind
Chemical Communications 2010 vol. 46(Issue 25) pp:4625-4626
Publication Date(Web):11 May 2010
DOI:10.1039/C0CC00360C
NMR studies of 13C/12C isotopic patterns in Cu(III) intermediates and reaction products together with DFT calculations of possible reaction pathways indicate an intermolecular SN2 like substitution mechanism for ligand exchange reactions in square planar Cu(III) complexes, which is proposed to be slow compared to reductive elimination at synthetic conditions.
Co-reporter:Chang-Zhi Li, Yutaka Matsuo, Takaaki Niinomi, Yoshiharu Sato and Eiichi Nakamura
Chemical Communications 2010 vol. 46(Issue 45) pp:8582-8584
Publication Date(Web):21 Oct 2010
DOI:10.1039/C0CC03028G
Treatment of [60]fullerene with potassium methylnaphthalenide and excess C6F5CH2Br afforded 1,4-bis(pentafluorobenzyl)[60]fullerene, the study of which showed that there is a face-to-face interaction between [60]fullerene and a perfluoro aromatic ring, allowing the molecule to be utilized for high-performance organic photovoltaic devices.
Co-reporter:Hayato Tsuji Dr.;Kosuke Sato;Yoshiharu Sato Dr. Dr.
Chemistry – An Asian Journal 2010 Volume 5( Issue 6) pp:1294-1297
Publication Date(Web):
DOI:10.1002/asia.201000093
Co-reporter:Yutaka Matsuo ; Sebastian Lacher ; Aiko Sakamoto ; Keiko Matsuo
The Journal of Physical Chemistry C 2010 Volume 114(Issue 41) pp:17741-17752
Publication Date(Web):September 17, 2010
DOI:10.1021/jp1059402
Conical-shaped penta(aryl)[60]fullerene thiol derivatives bearing one alkyl thiol linker surrounded by five phenyl or biphenyl groups were synthesized in good yield, and characterized by X-ray crystallographic analysis. These conical fullerene thiols were used for formation of self-assembled monolayers (SAMs) on gold surface in anaerobic and aerobic condition. Under nitrogen atmosphere, SAMs on gold were successfully prepared for all thiols (C60Ph5(CH2)3SH, C60Ph5(CH2)4SH, C60Ph5(CH2)6SH, C60(biphenyl)5(CH2)6SH) used in this work. The SAMs of penta(aryl)[60]fullerene thiols exhibited anodic and cathodic photocurrent generation upon light irradiation (λ = 400 nm) in the presence of sacrificial electron-donating and -accepting reagents, respectively. The SAM formation under air gave either SAMs or aggregates on gold depending on the length of alkyl chains of the linker. When the linker is long enough (i.e., C60Ph5(CH2)6SH) so that the disulfide group is not sterically protected (i.e., C60Ph5(CH2)6S−S(CH2)6C60Ph5), the molecules formed SAMs and generated anodic and cathodic photocurrent. Further aggregation of the molecules occurred when the linker is short relative to the arene cone consisting of five aryl groups (i.e., C60Ph5(CH2)3SH). These aggregates showed unusual anodic photocurrent behavior, likely because of diffusion issue for electrolyte and sacrificial reagents. The aggregates were further investigated by cyclic voltammetry, atomic force microscopy, and photoelectron yield spectroscopy.
Co-reporter:Koji Okamoto;Hiroyuki Isobe;Waka Nakanishi;Eisei Noiri;Kent Doi;Tatsuya Homma;Rui Maeda-Mamiya;Tetsuro Izumi;Takeshi Sugaya
PNAS 2010 Volume 107 (Issue 12 ) pp:5339-5344
Publication Date(Web):2010-03-23
DOI:10.1073/pnas.0909223107
Application of nanotechnology to medical biology has brought remarkable success. Water-soluble fullerenes are molecules with
great potential for biological use because they can endow unique characteristics of amphipathic property and form a self-assembled
structure by chemical modification. Effective gene delivery in vitro with tetra(piperazino)fullerene epoxide (TPFE) and its
superiority to Lipofectin have been described in a previous report. For this study, we evaluated the efficacy of in vivo gene
delivery by TPFE. Delivery of enhanced green fluorescent protein gene (EGFP) by TPFE on pregnant female ICR mice showed distinct
organ selectivity compared with Lipofectin; moreover, higher gene expression by TPFE was found in liver and spleen, but not
in the lung. No acute toxicity of TPFE was found for the liver and kidney, although Lipofectin significantly increased liver
enzymes and blood urea nitrogen. In fetal tissues, neither TPFE nor Lipofectin induced EGFP gene expression. Delivery of insulin
2 gene to female C57/BL6 mice increased plasma insulin levels and reduced blood glucose concentrations, indicating the potential
of TPFE-based gene delivery for clinical application. In conclusion, this study demonstrated effective gene delivery in vivo
for the first time using a water-soluble fullerene.
Co-reporter:Ting Chen, Ge-Bo Pan, Hui-Juan Yan, Li-Jun Wan, Yutaka Matsuo and Eiichi Nakamura
The Journal of Physical Chemistry C 2010 Volume 114(Issue 7) pp:3170-3174
Publication Date(Web):February 1, 2010
DOI:10.1021/jp9114173
The adsorption of four fullerene derivatives, including Re(C60Me5)(CO)3, Ru(C60Ph5)Cp, C60(C6H4C6H4−COOH)5Me, and C60(C6H4−CC−SiMe2C12H25)5Me, on a Au(111) surface has been investigated by scanning tunneling microscopy (STM) and cyclic voltammetry. High-resolution STM images reveal that Re(C60Me5)(CO)3 forms a well-ordered (2√3 × 2√3)R30° structure. Different from C60 on Au(111), the so-called “in-phase” structure is not found with the attachment of methyl and Re(CO)3 groups. With the increase of substituent size, disordered adlayers have been observed for Ru(C60Ph5)Cp and C60(C6H4C6H4−COOH)5Me. However, the individual molecules could be distinguished in STM images, suggesting that the two molecules interact strongly with the Au(111) surface. When the substituent size is further increased, a multilayered structure is formed for C60(C6H4−CC−SiMe2C12H25)5Me. This is because of molecular aggregation in the bulk solution, which occurs at very low concentration. These results indicate that the structures of fullerene derivatives play an essential role in adlayer formation through adjusting molecule−substrate and molecule−molecule interactions.
Co-reporter:Eiichi Nakamura;Hiroyuki Isobe
The Chemical Record 2010 Volume 10( Issue 5) pp:260-270
Publication Date(Web):
DOI:10.1002/tcr.201000021
Abstract
Long-range studies on the chemistry of two strained ring systems, cyclopropanes and fullerenes, converged on a challenge in biology, in vivo gene delivery. The new protocol of gene delivery employing a tailor-designed amino fullerene represents the third protocol after the two using virus and lipid delivery agents, none of which are universally useful. The amino fullerene delivers an EGFP and an insulin-2 gene to mice with efficiency superior to and selectivity distinct from those achieved by the conventional lipid-based delivery agents. The studies demonstrate the power of organic synthesis as driven by scientifically and socially important subjects. © 2010 The Japan Chemical Journal Forum and Wiley Periodicals, Inc. Chem Rec 10: 260–270; 2010: Published online in Wiley InterScience (www.interscience.wiley.com) DOI 10.1002/tcr.201000021
Co-reporter:Tatsuya Homma;Koji Harano Dr.;Hiroyuki Isobe Dr. Dr.
Angewandte Chemie 2010 Volume 122( Issue 9) pp:1709-1712
Publication Date(Web):
DOI:10.1002/ange.200904659
Co-reporter:Tatsuya Homma;Koji Harano Dr.;Hiroyuki Isobe Dr. Dr.
Angewandte Chemie International Edition 2010 Volume 49( Issue 9) pp:1665-1668
Publication Date(Web):
DOI:10.1002/anie.200904659
Co-reporter:Naohiko Yoshikai ; Hirokazu Matsuda
Journal of the American Chemical Society 2009 Volume 131(Issue 27) pp:9590-9599
Publication Date(Web):June 12, 2009
DOI:10.1021/ja903091g
We report here that hydroxyphosphine ligands (PO ligands) significantly accelerate nickel-catalyzed cross-coupling reactions of unreactive aryl electrophiles and Grignard reagents. The new catalytic system based on the nickel−PO−Grignard combination allows facile activation of unreactive aryl halides such as fluorides, chlorides, polyfluorides, and polychlorides as well as phenol derivatives such as carbamates and phosphates to give the corresponding cross-coupling products in good to excellent yields. We ascribe the high catalytic activity to a nickel phosphine/magnesium alkoxide bimetallic species that forms from the nickel precatalyst, the PO ligand, and the Grignard reagent and undergoes activation of the aryl−X bond by a cooperative push−pull action of the nucleophilic nickel and Lewis acidic magnesium centers. This mechanistic conjecture was corroborated by kinetic isotope effect experiments and density functional theory calculations. Being distinct from the conventional three-centered mechanism for oxidative addition, the proposed mechanism for the C−X bond activation offers a new concept for the design of cross-coupling reactions as well as other homogeneous catalyses involving activation of electrophilic substrates.
Co-reporter:Chang-Zhi Li ; Yutaka Matsuo
Journal of the American Chemical Society 2009 Volume 131(Issue 47) pp:17058-17059
Publication Date(Web):November 6, 2009
DOI:10.1021/ja907908m
A pseudo-D5d symmetric decaaryl[60]fullerene molecule has a rigid bow-tie shape and bears an emissive [10]cyclophenacene chromophore in the middle. It forms a smectic liquid crystalline mesophase that persists over a wide temperature range (e.g., from 17 to 257 °C) and shows yellow photoluminescence both in solution and in the solid state (inset in the POM image). Because of the alignment of the cyclophenacene chromophore in the lamellas, the bulk liquid crystals exhibit anisotropic photoluminescence.
Co-reporter:Yutaka Matsuo ; Yoshiharu Sato ; Takaaki Niinomi ; Iwao Soga ; Hideyuki Tanaka
Journal of the American Chemical Society 2009 Volume 131(Issue 44) pp:16048-16050
Publication Date(Web):October 16, 2009
DOI:10.1021/ja9048702
A new solution-processable fabrication protocol using a soluble tetrabenzoporphyrin (BP) precursor and bis(dimethylphenylsilylmethyl)[60]fullerene (SIMEF) created three-layered p-i-n photovoltaic devices, in which the i-layer possesses a well-defined bulk heterojunction structure in which columnar BP crystals grow vertically from the bottom p-layer. The device showed a power conversion efficiency of 5.2% (VOC = 0.75 V; JSC = 10.5 mA/cm2; FF = 0.65).
Co-reporter:Xiaozhang Zhu ; Chikahiko Mitsui ; Hayato Tsuji
Journal of the American Chemical Society 2009 Volume 131(Issue 38) pp:13596-13597
Publication Date(Web):September 3, 2009
DOI:10.1021/ja905626b
A variety of 1H-indenes, dihydro-s-indacenes, and diindenoindacenes, carbon-bridged phenylenevinylene derivatives, can be synthesized in good to high yields using as a synthetic module a 3-lithioindene compound made available by reductive cyclization of an alkynylbenzene derivative. The planar analogues of oligophenylenevinylene compounds thus synthesized show physical properties beneficial for use as ambipolar organic semiconductor materials.
Co-reporter:Yutaka Matsuo;Yoshiharu Sato;Masahiko Hashiguchi;Keiko Matsuo
Advanced Functional Materials 2009 Volume 19( Issue 14) pp:2224-2229
Publication Date(Web):
DOI:10.1002/adfm.200900021
Abstract
Three multifunctionalized organo[60]fullerene derivatives, C60Ph5(C6H4-tBu-4)5Me2 (cyclophenacene, 1), C60Ph5(C6H4-tBu-4)5Me2 (fused corannulene, 2), and C60Ph5(C6H4-tBu-4)3Me2 (phenylene-bridged fused corannulene, 3) are synthesized by the reaction of C60Ph5Me with 4-tert-butylphenylcopper reagent in the presence of pyridine, followed by treatment with MeI. Compounds 1–3 undergo reduction in the range from −1.8 to −2.5 V versus Fc/Fc+ and exhibit photoluminescence behavior with fluorescent quantum yields of 18.5%, 2.5%, and 3.2% with fluorescent lifetimes of 67, 1.1, and 27 ns (1–3, respectively). Organic electroluminescent diode devices using 1–3 are fabricated with π-conjugated polymers and show external electroluminescent efficiencies of 0.04%, 0.07%, and 0.03% emitting yellow, green, and red light, respectively. The device containing all three compounds emits white light. This result indicates that the bulky addends in 1–3 can effectively isolate the π-conjugated systems of the molecules in the solid state and retard the intermolecular excited-state quenching process.
Co-reporter:Hayato Tsuji, Kosuke Sato, Yoshiharu Sato and Eiichi Nakamura
Journal of Materials Chemistry A 2009 vol. 19(Issue 21) pp:3364-3366
Publication Date(Web):29 Apr 2009
DOI:10.1039/B906197E
A benzo[b]phosphole sulfide derivative DBPSB was found to function as a new class of n-type amorphous organic material, which features high electron drift mobility and high thermal stability, and the utility of this compound was demonstrated in an organic light-emitting diode.
Co-reporter:Hayato Tsuji, Iku Tanaka, Kohei Endo, Ken-ichi Yamagata, Masaharu Nakamura and Eiichi Nakamura
Organic Letters 2009 Volume 11(Issue 8) pp:1845-1847
Publication Date(Web):March 24, 2009
DOI:10.1021/ol9003542
A catalytic amount of In(NTf2)3 effects the inter- and intramolecular addition of a β-ketoester to an α,ω-diyne to produce a 1,3-dimethylenecycloalkane derivative in a single step. This [1 + n] annulation reaction shows good functional group tolerance and allows the synthesis of five- to seven-membered carbo- and heterocyclic as well as spirocyclic structures in moderate to excellent yields.
Co-reporter:Laurean Ilies, Hayato Tsuji and Eiichi Nakamura
Organic Letters 2009 Volume 11(Issue 17) pp:3966-3968
Publication Date(Web):August 7, 2009
DOI:10.1021/ol9015282
(2-Alkynylphenyl)silanes undergo intramolecular cyclization in the presence of an excess or a subequimolar amount of potassium hydride to give a variety of new 2-substituted benzosiloles in good to excellent yields. Some of these compounds showed a high fluorescence quantum yield both in solution and in the solid state, and they also showed reversible reduction in THF.
Co-reporter:Keiko Matsuo, Yutaka Matsuo, Akihiko Iwashita and Eiichi Nakamura
Organic Letters 2009 Volume 11(Issue 18) pp:4192-4194
Publication Date(Web):August 26, 2009
DOI:10.1021/ol901851g
The synthesis of a new class of fullerene derivatives, 1-imino-4-silylmethyl[60]fullerene derivatives, is described. The anion (C60R1−) of an alkyl- or aryl-adduct of [60]fullerene, C60R1H (R1 = CH2SiMe3, CH2SiMe2Ph, C6H4−OMe-4, C6H4−NMe2-4, C6H4−CF3-4 and C6H4−OMe-2), was allowed to react with a nitrilium salt [R2CNCH2SiMe3][OTf] (Tf = SO2CF3) that was generated in situ by the reaction of Me3SiCH2OTf and a nitrile solvent R1CN (R2 = Ph and Me). The desired imino[60]fullerene derivative C60(R1) [C(=NCH2SiMe3)R2] was produced in a yield up to 80%. The structure of the product with R1 = C6H4−OMe-4 and R2 = Ph was determined by single-crystal X-ray analysis.
Co-reporter:Naohiko Yoshikai;Kotaro Miura
Advanced Synthesis & Catalysis 2009 Volume 351( Issue 7-8) pp:1014-1018
Publication Date(Web):
DOI:10.1002/adsc.200900054
Co-reporter:Yutaka Matsuo ;Kazukuni Tahara Dr.;Takeshi Fujita
Angewandte Chemie International Edition 2009 Volume 48( Issue 34) pp:6239-6241
Publication Date(Web):
DOI:10.1002/anie.200902185
Co-reporter:Naohiko Yoshikai Dr.;Arimasa Matsumoto;Jakob Norinder Dr. Dr.
Angewandte Chemie International Edition 2009 Volume 48( Issue 16) pp:2925-2928
Publication Date(Web):
DOI:10.1002/anie.200900454
Co-reporter:Naohiko Yoshikai Dr.;Arimasa Matsumoto;Jakob Norinder Dr. Dr.
Angewandte Chemie 2009 Volume 121( Issue 16) pp:2969-2972
Publication Date(Web):
DOI:10.1002/ange.200900454
Co-reporter:Yutaka Matsuo, Akihiko Iwashita, Hiromi Oyama, Eiichi Nakamura
Tetrahedron Letters 2009 50(26) pp: 3411-3413
Publication Date(Web):
DOI:10.1016/j.tetlet.2009.02.155
Co-reporter:Hayato Tsuji Dr.;Yuki Yokoi;Chikahiko Mitsui;Laurean Ilies;Yoshiharu Sato Dr. Dr.
Chemistry – An Asian Journal 2009 Volume 4( Issue 5) pp:655-657
Publication Date(Web):
DOI:10.1002/asia.200800471
Co-reporter:Yutaka Matsuo and Eiichi Nakamura
Chemical Reviews 2008 Volume 108(Issue 8) pp:3016
Publication Date(Web):July 25, 2008
DOI:10.1021/cr0684218
Co-reporter:Naohiko Yoshikai;Ryoko Iida
Advanced Synthesis & Catalysis 2008 Volume 350( Issue 7-8) pp:1063-1072
Publication Date(Web):
DOI:10.1002/adsc.200800060
Abstract
The mechanism of nucleophilic substitution reaction at an sp2 carbon center of a thioester or an acid chloride with a lithium organocuprate reagent has been investigated. Density functional calculations indicated that the thioester undergoes oxidative addition of the CS bond to the copper(I) atom through a three-centered transition state to afford an organocopper(III) intermediate, which gives the product through reductive elimination of the alkyl and the acyl groups. On the other hand, the acid chloride loses a chloride anion very easily when it interacts with the cuprate, because the chloride anion is captured by a lithium(I) cation rather than a copper(I) atom. 13C kinetic isotope effect (KIE) experiments showed excellent agreement with computational predictions for the thioester reaction, but suggested that the nucleophilic displacement transition state of the acid chloride occurs much more advanced than the calculations predict.
Co-reporter:Yutaka Matsuo, Akihiko Iwashita and Eiichi Nakamura
Organometallics 2008 Volume 27(Issue 18) pp:4611-4617
Publication Date(Web):August 23, 2008
DOI:10.1021/om800308n
A molybdenum pentamethyl[60]fullerene bromo tricarbonyl complex, Mo(η5-C60Me5)Br(CO)3 (3), was successfully synthesized by the reaction of C60Me5Br (2) with Mo(CO)3(EtCN)3. Treatment of 3 with I2 afforded an iodo complex, Mo(η5-C60Me5)I(CO)3 (4). The reaction employing C60Me5K (5) prepared from C60Me5H (1) and KH, followed by treatment with Mo(CO)3(EtCN)3 and then Diazald, gave a nitrosyl complex, Mo(η5-C60Me5)(NO)(CO)2 (6). Complex 6 was converted to a molybdenum(IV) complex, Mo(η5-C60Me5)Cl2(NO)(CO) (7), by the reaction with PCl5. A molybdenum(VI) complex, Mo(η5-C60Me5)O2Br (8), was obtained by exposure of 3 in air. Tungsten- and chromium-nitrosyl complexes, W(η5-C60Me5)(NO)(CO)2 (9) and Cr(η5-C60Me5)(NO)(CO)2 (10), were synthesized similarly to 6. Complex 10 gave a dithiocarbonate complex, Cr(η5-C60Me5)(η5-S2COEt)(NO) (11) through the reaction among 10, ethanol, and carbon disulfide. Compounds 1, 3, 4, 6, 8, and 11 were characterized by X-ray crystallography.
Co-reporter:Yutaka Matsuo, Yoichiro Kuninobu, Ayako Muramatsu, Masaya Sawamura and Eiichi Nakamura
Organometallics 2008 Volume 27(Issue 14) pp:3403-3409
Publication Date(Web):June 21, 2008
DOI:10.1021/om8001262
K(C60R5) (1, R = Me, Ph) was generated by deprotonation of C60R5H (2) and allowed to react with N-fluoropyridinium triflate and N-chloro- and N-bromosuccinimide in benzene at 25 °C for 10 min to obtain halogenated fullerenes C60R5X (3a: R = Me, X = F; 3b: R = Me, X = Cl; 3c: R = Me, X = Br; 4a: R = Ph, X = F; 4b: R = Ph, X = Cl, 4c: R = Ph, X = Br) in good yield. The pentamethyl[60]fullerene halides are useful for the synthesis of a variety of η5-fullerene metal complexes. The reaction of the fullerene bromide 3c with the low-valent transition metal complexes Na[Re(CO)4], Fe(CO)5, Ru3(CO)12, and Na[Co(CO)4] gave Re(η5-C60Me5)(CO)3 (5), Fe(η5-C60Me5)Br(CO)2 (6), Ru(η5-C60Me5)Br(CO)2 (7), and Co(η5-C60Me5)(CO)2 (8), respectively. The structures of halide 3c and rhenium complex 5 were determined by X-ray crystallography. Electrochemical measurements on 3b and 3c were also performed. The iron complex 6 was converted into Fe(η5-C60Me5)Cp (9), Fe(η5-C60Me5)Me(CO)2 (10), Fe(η5-C60Me5)(CO)2(CCH) (11), and Fe(η5-C60Me5)(CO)2(CCPh) (12), by ligand exchange reactions.
Co-reporter:Yutaka Matsuo;Takashi Uematsu
European Journal of Inorganic Chemistry 2007 Volume 2007(Issue 18) pp:
Publication Date(Web):12 APR 2007
DOI:10.1002/ejic.200700013
η1-Allyl and η3-allyl, ethyl, and hydrido ruthenium complexes of pentamethyl[60]fullerene, Ru(η5-C60Me5)R(CO)2(R = η1-allyl, Et, H) and Ru(η5-C60Me5)(η3-allyl)(CO) were synthesized by the reaction of a chlorido complex Ru(η5-C60Me5)Cl(CO)2 with an allyl and an ethyl Grignard reagent or lithium aluminum hydride. Conversion of the η1-allyl complex to the corresponding η3-allyl complex and the catalytic performance of the hydrido and the chlorido complexes in the isomerization reaction of 1-decene to internal decenes are described. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Co-reporter:Hayato Tsuji Dr.;Ken-ichi Yamagata;Yoshimitsu Itoh Dr.;Kohei Endo Dr.;Masaharu Nakamura Dr. Dr.
Angewandte Chemie International Edition 2007 Volume 46(Issue 42) pp:
Publication Date(Web):18 SEP 2007
DOI:10.1002/anie.200702928
Many different sizes of rings available: Heating ω-alkynyl-β-ketoesters in the presence of In(NTf2)3 (Tf=trifluoromethanesulfonyl) produces six- to fifteen-membered ring products in good yields. The reaction features low catalyst loading and moderately dilute conditions, and the formation of medium-sized rings is sometimes faster than that for the corresponding six-membered rings. A synthesis of (±)-muscone is also reported.
Co-reporter:Yutaka Matsuo Dr.;Kazukuni Tahara Dr.;Kouhei Morita;Keiko Matsuo Dr.
Angewandte Chemie International Edition 2007 Volume 46(Issue 16) pp:
Publication Date(Web):6 MAR 2007
DOI:10.1002/anie.200604839
The amount of pyridine (py) is essential for the outcome of the efficient addition of aryl copper compounds to [60]fullerene on a 20-mg to 1-g scale (see scheme). It controls—in addition to the installation of an ortho-methyl group on the aryl reagent—the regioselectivity and the number of aryl groups introduced. The tenfold-addition adduct may be further converted into the corresponding double-decker metallocene.
Co-reporter:Akihiko Iwashita;Yutaka Matsuo Dr.
Angewandte Chemie International Edition 2007 Volume 46(Issue 19) pp:
Publication Date(Web):27 MAR 2007
DOI:10.1002/anie.200700062
Functionalization of fullerenes can be achieved inexpensively by Friedel–Crafts reaction. For instance, treatment of [60]fullerene with AlCl3 in toluene gave mono-, di-, and tritolyltrihydro[60]fullerenes in moderate to good yields (see scheme). The structures of the products were determined by crystallography and derivatization.
Co-reporter:Yutaka Matsuo Dr.;Kazukuni Tahara Dr.;Kouhei Morita;Keiko Matsuo Dr.
Angewandte Chemie 2007 Volume 119(Issue 16) pp:
Publication Date(Web):6 MAR 2007
DOI:10.1002/ange.200604839
Die Menge an Pyridin (py) ist für den Verlauf der effizienten Addition von Arylkupferverbindungen an [60]Fulleren im 20-mg- bis 1-g-Maßstab entscheidend (siehe Schema). Sie bestimmt – zusätzlich zum Einbau einer ortho-Methylgruppe in das Arylreagens – die Regioselektivität und die Zahl der eingeführten Arylgruppen. Das Addukt mit zehn Addenden kann in das entsprechende Doppeldeckermetallocen überführt werden.
Co-reporter:Akihiko Iwashita;Yutaka Matsuo Dr.
Angewandte Chemie 2007 Volume 119(Issue 19) pp:
Publication Date(Web):27 MAR 2007
DOI:10.1002/ange.200700062
Die Funktionalisierung von Fullerenen gelingt preiswert durch Friedel-Crafts-Reaktion. So liefert die Behandlung von [60]Fulleren mit AlCl3 in Toluol Mono-, Di- und Tritolyltrihydro[60]fullerene in mäßigen bis guten Ausbeuten (siehe Schema). Die Strukturen der Produkte wurden durch Kristallographie und Derivatisierung bestimmt.
Co-reporter:Hayato Tsuji Dr.;Ken-ichi Yamagata;Yoshimitsu Itoh Dr.;Kohei Endo Dr.;Masaharu Nakamura Dr. Dr.
Angewandte Chemie 2007 Volume 119(Issue 42) pp:
Publication Date(Web):18 SEP 2007
DOI:10.1002/ange.200702928
In vielen Größen erhältlich: Erhitzen von ω-Alkinyl-β-ketoestern in Gegenwart von In(NTf2)3 (Tf=Trifluormethansulfonyl) ergibt cyclische Produkte mit sechs- bis fünfzehngliedrigen Ringen in guten Ausbeuten. Die Reaktion gelingt mit niedrigen Katalysatorbeladungen und bei mäßig verdünnten Bedingungen, und Ringe mittlerer Größe werden in einigen Fällen schneller gebildet als die entsprechenden sechsgliedrigen Ringe. Eine Synthese von (±)-Muscon wird ebenfalls beschrieben.
Co-reporter:Tatsuya Homma;Hiroyuki Isobe
PNAS 2007 Volume 104 (Issue 38 ) pp:14895-14898
Publication Date(Web):2007-09-18
DOI:10.1073/pnas.0705010104
Lipid bilayer membranes are important as fundamental structures in biology and possess characteristic water-permeability,
stability, and mechanical properties. Water permeation through a lipid bilayer membrane occurs readily, and more readily at
higher temperature, which is largely due to an enthalpy cost of the liquid-to-gas phase transition of water. A fullerene bilayer
membrane formed by dissolution of a water-soluble fullerene, Ph5C60K, has now been shown to possess properties entirely different from those of the lipid membranes. The fullerene membrane is
several orders of magnitude less permeable to water than a lipid membrane, and the permeability decreases at higher temperature.
Water permeation is burdened by a very large entropy loss and may be favored slightly by an enthalpy gain, which is contrary
to the energetics observed for the lipid membrane. We ascribe this energetics to favorable interactions of water molecules
to the surface of the fullerene molecules as they pass through the clefts of the rigid fullerene bilayer. The findings provide
possibilities of membrane design in science and technology.
Co-reporter:Yutaka Matsuo Dr.;Takeshi Fujita
Chemistry – An Asian Journal 2007 Volume 2(Issue 8) pp:948-955
Publication Date(Web):6 JUL 2007
DOI:10.1002/asia.200700124
Potassium reduction of iron– and ruthenium–penta(organo)[60]fullerene complexes, [M(η5-C60R5)(η5-Cp)] (1 a: M=Fe, R=Ph; 1 b: M=Fe, R=Me; 1 c: M=Ru, R=Ph; 1 d: M=Ru, R=Me; Cp=C5H5) gave mono- and dianions of these complexes. Treatment of the dianion 1 a with α-bromodiphenylmethane gave three different iron–hepta(organo)[60]fullerenes, [Fe{η5-C60Ph5(CHPh2)2}(η5-Cp)], as a mixture of regioisomers. All three compounds were fully characterized by physical methods, including X-ray crystallography and electrochemical measurements. One of the three compounds contains a new hoop-shaped condensed aromatic system.
Co-reporter:Yutaka Matsuo Dr.;Yu-Wu Zhong Dr.
Chemistry – An Asian Journal 2007 Volume 2(Issue 3) pp:358-366
Publication Date(Web):8 FEB 2007
DOI:10.1002/asia.200600341
Ruthenium complexes that bear both a fullerene and an allenylidene ligand, [Ru(C60Me5)((R)-prophos)=CCCR1R2]PF6 (prophos=1,2-bis(diphenylphosphanyl)propane), were prepared by the reaction of [Ru(C60Me5)Cl((R)-prophos)] and a propargyl alcohol in better than 90 % yields, and characterized by 1H, 13C, and 31P NMR, IR, and UV/Vis/NIR spectroscopy and MS. Cyclic voltammograms of these complexes showed one reversible or irreversible reduction wave due to the allenylidene part, and two reversible reduction waves due to the fullerene core. Nucleophilic addition of RMgBr or RLi proceeded regioselectively at the distal carbon atom of the allenylidene array. The reaction took place with a 60:40–95:5 level of diastereoselectivity with respect to the original chirality in the (R)-prophos ligand, which is located six atoms away from the electrophilic carbon center.
Co-reporter:Hiroyuki Takamatsu Dr.;Yoshihiro Murakami Dr.;Hideki Yorimitsu Dr.;Shintaro Nishimura Dr. Dr.
Chemistry – An Asian Journal 2007 Volume 2(Issue 1) pp:57-65
Publication Date(Web):5 DEC 2006
DOI:10.1002/asia.200600271
In positron emission tomography (PET), which exploits the affinity of a radiopharmaceutical for the target organ, a systematic repertoire of oxygen-15-labeled PET tracers is expected to be useful for bioimaging owing to the ubiquity of oxygen atoms in organic compounds. However, because of the 2-min half-life of 15O, the synthesis of complex biologically active 15O-labeled organic molecules has not yet been achieved. A state-of-the-art synthesis now makes available an 15O-labeled complex organic molecule, 6-[15O]-2-deoxy-D-glucose. Ultrarapid radical hydroxylation of 2,6-dideoxy-6-iodo-D-glucose with molecular oxygen labeled with 15O of two-minute half-life provided the target 15O-labeled molecule. The labeling reaction with 15O was complete in 1.3 min, and the entire operation time starting from the generation of 15O-containing dioxygen by a cyclotron to the purification of the labeled sugar was 7 min. The labeled sugar accumulated in the metabolically active organs as well as in the bladder of mice and rats. 15O-labeling offers the possibility of repetitive scanning and the use of multiple PET tracers in the same body within a short time, and hence should significantly expand the scope of PET studies of small animals.
Co-reporter:Masanori Koshino;Takatsugu Tanaka;Niclas Solin;Kazutomo Suenaga;Hiroyuki Isobe
Science 2007 Volume 316(Issue 5826) pp:853
Publication Date(Web):11 May 2007
DOI:10.1126/science.1138690
Abstract
High-resolution transmission electron microscopy revealed nearly atomically precise images of stepping conformational change and translational motion of single hydrocarbon molecules confined in carbon nanotubes. One or two C12 or C22 alkyl chains were tethered to a carborane end group and then embedded in the nanotubes. Images of the hydrocarbon chains interacting with each other and with a graphitic surface provide information on three-dimensional structures and dynamic molecular interactions that cannot be obtained by other analytical methods.
Co-reporter:Yutaka Matsuo, Eiichi Nakamura
Inorganica Chimica Acta 2006 Volume 359(Issue 6) pp:1979-1982
Publication Date(Web):10 April 2006
DOI:10.1016/j.ica.2005.07.021
The reaction of [60]fullerene with Me3SiCH2MgCl in 1,2-Cl2C6H4/THF (1/1) under dry air afforded a bis-alkyl adduct, C60(CH2SiMe3)2 (1), in 54% yield. Treatment of 1 with Me3SiCH2MgCl in THF under argon then afforded a trialkyl[60]fullerene, C60(CH2SiMe3)3H (2), in 37% yield. Further treatment of 2 with KOtBu gave a potassium salt, [K(thf)n][C60(CH2SiMe3)3] (3), which was then converted to a Cs-symmetric Rh(I) complex, Rh[η5-C60(CH2SiMe3)3](1,5-cyclooctadiene) (4), in 91% yield.We have achieved the synthesis of a new class of tri-organo[60]fullerene, C60(CH2SiMe3)3H, which is based on an improvement synthesis of C60(CH2SiMe3)2. Preparation of the rhodium complex, Rh[C60(CH2SiMe3)3](1,5-cyclooctadiene), is described.
Co-reporter:Masaharu Nakamura Dr.;Laurean Ilies;Saika Otsubo Dr.
Angewandte Chemie 2006 Volume 118(Issue 6) pp:
Publication Date(Web):30 DEC 2005
DOI:10.1002/ange.200502920
Zink schließt den Ring: Durch metallierende Cyclisierung wurden 2-Alkinylphenole oder -aniline in thermisch stabile und dennoch reaktive 3-Zinciobenzofurane bzw. -indole überführt, die in Pd-katalysierten Kreuzkupplungen mit Mono- wie Polyhalogenarenen oder -alkenen in π-konjugierte Verbindungen umgewandelt wurden (siehe Schema, Bn=Benzyl).
Co-reporter:Hiroyuki Isobe Dr.;Takatsugu Tanaka;Rui Maeda;Eisei Noiri Dr.;Niclas Solin Dr.;Masako Yudasaka Dr.;Sumio Iijima
Angewandte Chemie International Edition 2006 Volume 45(Issue 40) pp:
Publication Date(Web):15 SEP 2006
DOI:10.1002/anie.200601718
The risk assessment of carbon materials, an important topic in nanomaterials research, has been hampered by the lack of characterizable samples. Transition-metal-free carbon nanohorn aggregates have been prepared that are covalently bonded aggregates of single-walled nanotubes. They were functionalized to give water-soluble derivatives (see picture), which were incubated with cells in cytotoxicity assessments.
Co-reporter:Hiroyuki Isobe Dr.;Waka Nakanishi Dr.;Naoki Tomita Dr.;Shigeki Jinno Dr.;Hiroto Okayama
Chemistry – An Asian Journal 2006 Volume 1(Issue 1-2) pp:
Publication Date(Web):4 JUL 2006
DOI:10.1002/asia.200600051
A series of aminofullerenes that share a common structural motif have been synthesized and subjected to a systematic investigation of structure activity relationship regarding their ability for transient transfection and cytotoxicity. DNA-binding tests indicated that any water-soluble fullerene-bearing amino group would bind to double-stranded DNA. For these molecules to be effective transfection reagents, however, they require additional structural features. First, the molecule must be capable of producing submicrometer-sized fullerene/DNA aggregates that can be internalized into mammalian cells through endocytosis. Second, the molecule must be capable of releasing DNA as the aggregates are transferred into the cytoplasm. This can be achieved in at least two ways: by loss of the DNA-binding amino groups from the fullerene core, and by transformation of the amino groups to neutral groups such as amides. The screening experiments led us to identify the best reagent, a tetrapiperidinofullerene, that can be synthesized in two steps from fullerene, piperazine, and molecular oxygen, and that is more efficient at transfection than a commonly used lipid-based transfection reagent.
Co-reporter:Naohiko Yoshikai;Tatsuya Yamashita
Chemistry – An Asian Journal 2006 Volume 1(Issue 3) pp:
Publication Date(Web):12 JUL 2006
DOI:10.1002/asia.200600034
Regioselective reaction of a lithium organocuprate (R2CuLi) and a polyconjugated carbonyl compound affords a remote-conjugate-addition product. This reaction proceeds particularly cleanly when the conjugation is terminated by a CC triple bond. The reaction pathways and the origin of the regioselectivity of this class of transformations are explored with the aid of density functional calculations. The outline of the reaction pathway is as follows. An initially formed β-cuprio(III) enolate intermediate undergoes smooth copper migration along the conjugated system. This process takes place faster than reductive elimination of intermediary σ/π-allylcopper(III) species, since the latter reaction disrupts the conjugation in the substrate and hence is not preferred. The copper migration to the acetylenic terminal affords a σ/π-allenylcopper(III) intermediate, which undergoes facile and selective CC bond forming reductive elimination at the terminal carbon atom. The present mechanistic framework shows good agreement with some pertinent experimental data, including 13C NMR chemical shifts and kinetic isotope effects.
Co-reporter:Masaharu Nakamura, Laurean Ilies, Saika Otsubo,Eiichi Nakamura
Angewandte Chemie International Edition 2006 45(6) pp:944-947
Publication Date(Web):
DOI:10.1002/anie.200502920
Co-reporter:Hiroyuki Isobe, Sota Sato, Jae Wook Lee, Hee-Joon Kim, Kimoon Kim and Eiichi Nakamura
Chemical Communications 2005 (Issue 12) pp:1549-1551
Publication Date(Web):31 Jan 2005
DOI:10.1039/B417999D
Thread-in-hole complexation of cucurbit[6]uril (CB[6]) with spermidine and spermine either enhances or reduces the activity of the polyamine on the enzymatic reactions of DNA.
Co-reporter:Masaharu Nakamura;Kohei Endo
Advanced Synthesis & Catalysis 2005 Volume 347(Issue 11-13) pp:
Publication Date(Web):19 OCT 2005
DOI:10.1002/adsc.200505206
A modular synthesis of α-arylated carbonyl compounds has been achieved by the combination of an indium-catalyzed regioselective addition of β-keto esters to conjugated diynes and a palladium-catalyzed benzannulation reaction. Indium tris(bistriflylamide), In(NTf2)3, was found to be an efficient catalyst for the first addition reaction of β-keto esters to diynes. The reaction proceeds with perfect regioselectivity to give conjugated enynes in high yield. The second palladium-catalyzed benzannulation proceeds in high to excellent yield and with high regioselectivity for a variety of diynes. This two-step α-arylation of carbonyl compounds thus proceeds in a catalytic manner without loss of elements in the starting materials. The reaction may be performed in a single pot without isolation of the product of the first step.
Co-reporter:Hideki Yorimitsu Dr.;Yoshihiro Murakami Dr.;Hiroyuki Takamatsu Dr.;Shintaro Nishimura Dr.
Angewandte Chemie International Edition 2005 Volume 44(Issue 18) pp:
Publication Date(Web):12 APR 2005
DOI:10.1002/anie.200500044
Make it quick! The oxygen isotope 15O has a half-life of only 2 min, and was incorporated into a sugar through an ultra-rapid radical hydroxylation of 2,6-dideoxy-6-iodo-D-glucose with labeled molecular oxygen to provide 6-[15O]-2-deoxy-D-glucose (see scheme). The product accumulates in metabolically active organs of rats similarly to a 18F-based tracer in common use, and represents a promising alternative for medical imaging.
Co-reporter:Hideki Yorimitsu Dr.;Yoshihiro Murakami Dr.;Hiroyuki Takamatsu Dr.;Shintaro Nishimura Dr.
Angewandte Chemie 2005 Volume 117(Issue 18) pp:
Publication Date(Web):12 APR 2005
DOI:10.1002/ange.200500044
Es muss schnell gehen! Das Sauerstoffisotop 15O, das eine Halbwertszeit von nur 2 min hat, wurde durch eine ultraschnelle radikalische Hydroxylierung, bei der 2,6-Didesoxy-6-iod-D-glucose durch markierten molekularen Sauerstoff in 6-[15O]-2-Desoxy-D-glucose umgewandelt wird, in ein Zuckermolekül eingebaut (siehe Schema). Das Produkt reichert sich auf ähnliche Weise wie ein gängiger 18F-Tracer in metabolisch aktiven Organen der Ratte an, was es zu einem vielversprechenden Mittel für Bildgebungsverfahren in der Medizin macht.
Co-reporter:Naohiko Yoshikai Dr.;Tatsuya Yamashita Dr.
Angewandte Chemie International Edition 2005 Volume 44(Issue 30) pp:
Publication Date(Web):29 JUN 2005
DOI:10.1002/anie.200501107
Passing the buck: Rapid copper migration along the conjugated system results in regioselective remote conjugate addition of a lithium organocuprate to a polyenynyl carbonyl compound, as revealed by density-functional calculations (see scheme). The unique structural/electronic properties of the σ/π-allenyl–copper(III) intermediates are responsible for the selective CC bond formation at the terminal acetylenic position.
Co-reporter:Naohiko Yoshikai Dr.;Tatsuya Yamashita Dr.
Angewandte Chemie 2005 Volume 117(Issue 30) pp:
Publication Date(Web):29 JUN 2005
DOI:10.1002/ange.200501107
Staffellauf: Die schnelle Wanderung von Kupfer entlang dem konjugierten System führt zur regioselektiven entfernten konjugierten Addition eines Lithiumorganocuprats an eine Polyeninylcarbonylverbindung, wie Dichtefunktionalrechnungen ergaben (siehe Schema). Die einzigartigen strukturellen/elektronischen Eigenschaften der σ/π-Allenyl-Kupfer(III)-Intermediate sind für die selektive C-C-Bindungsbildung an der terminalen acetylenischen Position ursächlich.
Co-reporter:Masaharu Nakamura Dr.;Alakana Hajra Dr.;Kohei Endo Dr.
Angewandte Chemie 2005 Volume 117(Issue 44) pp:
Publication Date(Web):17 OCT 2005
DOI:10.1002/ange.200502703
Ein innovatives Konzept liefert die optisch aktiven α-Fluorketone 3 in hohen Ausbeuten und mit bis zu 99 % ee ausgehend von racemischen α-Fluor-β-ketoestern 1 in Gegenwart des chiralen Phosphanyloxazolin-Liganden 2. Durch diese palladiumkatalysierte Decarboxylierung/Allylierung können überdies ausschließlich kohlenstoffsubstituierte quartäre Stereozentren hoch enantioselektiv aufgebaut werden. dba=Dibenzylidenaceton.
Co-reporter:Masaharu Nakamura, Alakananda Hajra, Kohei Endo,Eiichi Nakamura
Angewandte Chemie International Edition 2005 44(44) pp:7248-7251
Publication Date(Web):
DOI:10.1002/anie.200502703
Co-reporter:Eiichi Nakamura
Journal of Organometallic Chemistry 2004 Volume 689(Issue 24) pp:4630-4635
Publication Date(Web):29 November 2004
DOI:10.1016/j.jorganchem.2004.08.009
An idea of making a ferrocene/fullerene hybrid, “bucky ferrocene”, has intrigued chemists for some time, but the compounds remained to be hypothetical. The synthesis of such hybrid molecules as Fe(C60Me5)Cp, Ru(C60Me5)Cp and Fe(C70Me3)Cp as well as their functionalized derivatives from [60] and [70]fullerenes has been achieved in recent years. With their esthetically pleasing structures and the dual character of metallocene and graphite, these molecules may stimulate the interest of both chemists and non-chemists.An idea of making a ferrocene/fullerene hybrid, “bucky ferrocene”, has intrigued chemists for some time, but the compounds remained to be hypothetical. The synthesis of such hybrid molecules as Fe(C60Me5)Cp, Ru(C60Me5)Cp and Fe(C70Me3)Cp as well as their functionalized derivatives from [60] and [70]fullerenes has been achieved in recent years. With their esthetically pleasing structures and the dual character of metallocene and graphite, these molecules may stimulate the interest of both chemists and non-chemists.
Co-reporter:Ayako Hashimoto;Hiroyuki Isobe;Kumiko Ajima;Hideki Yorimitsu;Sumio Iijima;Jin Miyawaki;Kazutomo Suenaga;Masako Yudasaka
PNAS 2004 Volume 101 (Issue 23 ) pp:8527-8530
Publication Date(Web):2004-06-08
DOI:10.1073/pnas.0400596101
Selective synthesis of particles of angstrom to nanometer size consisting of one to many metal atoms is instrumental in various
applications, but it has been hampered by the tendency of the metal atom to form large clusters. We found, as studied by the
state-of-the-art electron microscopic technique, a strategy to produce metal-containing nanoparticles isolated from each other
by depositing metal atoms in a hydrophilic hole on or in the interior of a carbon nanotube as demonstrated by the reaction
of Gd(OAc)3 with oxidized single-wall nanohorns. Besides the potential utilities of the deposited metal clusters, the metal deposition
protocol provides a method to control permeation of molecules through such openings.
Co-reporter:Naohiko Yoshikai
Advanced Synthesis & Catalysis 2003 Volume 345(Issue 9-10) pp:
Publication Date(Web):26 SEP 2003
DOI:10.1002/adsc.200303092
Theoretical studies on the stereoselectivity of the dirhodium tetracarboxylate (carboxamidate)-catalyzed intramolecular CH insertion reaction, which gives a variety of carbo- or heterocyclic compounds, have been performed by the following procedure. First, the CH insertion mechanism of simple systems was studied by the hybrid density functional theory (B3LYP) calculations. On the basis of these B3LYP structures, stereoselectivities of the reactions of realistic substrates were examined by the PM3 calculations with some structural constraints. The origin of the diastereo- and enantioselectivities in the four- and five-membered ring formation reactions with an achiral or a chiral Rh catalyst has thus been elucidated.
Co-reporter:Motoki Toganoh, Kazuhiro Suzuki, Rie Udagawa, Atsushi Hirai, Masaya Sawamura and Eiichi Nakamura
Organic & Biomolecular Chemistry 2003 vol. 1(Issue 14) pp:2604-2611
Publication Date(Web):16 Jun 2003
DOI:10.1039/B302468G
Treatment of a 1,7-diorgano[60]fullerene with Grignard reagents or organocopper reagents affords a [60]fullerene indenide or a [60]fullerene cyclopentadienide regioselectively in good to excellent yields. These reactions gave an insight into the reaction mechanism of the organocopper penta-addition reaction of [60]fullerene, giving [60]fullerene cyclopentadienide in quantitative yield.
Co-reporter:Motoki Toganoh Dr.;Yutaka Matsuo Dr. Dr.
Angewandte Chemie International Edition 2003 Volume 42(Issue 30) pp:
Publication Date(Web):11 JUL 2003
DOI:10.1002/anie.200351722
Functionalizing fullerenes: The first regioselective polyhydrogenation of [60]fullerene has been achieved. Upon treatment of [60]fullerene or its derivative with 9,10-dihydroanthracene in the presence of [Re2(CO)10], transfer hydrometallation reaction takes place to give a polyhydrogenation product (see scheme). The reaction provided a pathway to a variety of metal η5 complexes of hydrofullerenes.
Co-reporter:Motoki Toganoh Dr.;Yutaka Matsuo Dr. Dr.
Angewandte Chemie 2003 Volume 115(Issue 30) pp:
Publication Date(Web):11 JUL 2003
DOI:10.1002/ange.200351722
Fullerene funktionalisieren: Die erste regioselektive Mehrfachhydrierung von C60 wurde erreicht durch Umsetzung mit 9,10-Dihydroanthracen in Gegenwart von [Re2(CO)10] (siehe Schema). Diese Reaktion eröffnet einen Zugang zu einer Reihe η5-gebundener Metallkomplexe von teilhydrierten Fullerenen.
Co-reporter:Masaya Sawamura, Motoki Toganoh, Hitoshi Iikura, Yutaka Matsuo, Atsushi Hirai and Eiichi Nakamura
Journal of Materials Chemistry A 2002 vol. 12(Issue 7) pp:2109-2115
Publication Date(Web):10 May 2002
DOI:10.1039/B202130G
A variety of [70]fullerene derivatives bearing three organic groups C70R3H (1, R = aryl, methyl) have been synthesized in 90–99% isolated yield by the reaction of [70]fullerene with a Grignard reagent in the presence of CuBr·S(CH3)2. Deprotonation of C70R3H with a metal alkoxide gave the corresponding metal complex M(η5-C70R3)
[M = K (2), Tl (3)]. X-ray crystallographic analysis as well as theoretical study revealed the nature of the 68π-electron ligand, C70R3−.
Co-reporter:Masaya Sawamura,
Kenji Kawai,
Yutaka Matsuo,
Kiyoshi Kanie,
Takashi Kato
and
Eiichi Nakamura
Nature 2002 419(6908) pp:702
Publication Date(Web):
DOI:10.1038/nature01110
Polar liquid crystalline materials can be used in optical and electronic applications, and recent interest has turned to formation strategies that exploit the shape of polar molecules and their interactions to direct molecular alignment1, 2. For example, banana-shaped molecules align their molecular bent within smectic layers3, whereas conical molecules should form polar columnar assemblies4, 5, 6, 7, 8, 9. However, the flatness of the conical molecules used until now4, 5, 6, 9 and their ability to flip7, 8 have limited the success of this approach to making polar liquid crystalline materials. Here we show that the attachment of five aromatic groups to one pentagon of a C60 fullerene molecule yields deeply conical molecules that stack into polar columnar assemblies. The stacking is driven by attractive interactions between the spherical fullerene moiety and the hollow cone formed by the five aromatic side groups of a neighbouring molecule in the same column. This packing pattern is maintained when we extend the aromatic groups by attaching flexible aliphatic chains, which yields compounds with thermotropic and lyotropic liquid crystalline properties. In contrast, the previously reported fullerene-containing liquid crystals10, 11, 12, 13, 14, 15, 16, 17 all exhibit thermotropic properties only, and none of them contains the fullerene moiety as a functional part of its mesogen units. Our design strategy should be applicable to other molecules and yield a range of new polar liquid crystalline materials.
Co-reporter:Hiroyuki Isobe Dr.;Sho Sugiyama;Ken-ichi Fukui Dr.;Yasuhiro Iwasawa Dr. Dr.
Angewandte Chemie International Edition 2001 Volume 40(Issue 18) pp:
Publication Date(Web):14 SEP 2001
DOI:10.1002/1521-3773(20010917)40:18<3364::AID-ANIE3364>3.0.CO;2-S
DNA condensation by a fullerene vector has been imaged at the molecular level by atomic force microscopy (AFM); analysis of a mixture of plasmid DNA and DNA-binding fullerene with the aid of this carbonaceous vector provided the first information on the mechanism of transfection. The picture shows AFM images of pBR322 DNA in the absence of (left) and partially condensed by the fullerene (right).
Co-reporter:Hiroyuki Isobe Dr.;Sho Sugiyama;Ken-ichi Fukui Dr.;Yasuhiro Iwasawa Dr. Dr.
Angewandte Chemie 2001 Volume 113(Issue 18) pp:
Publication Date(Web):14 SEP 2001
DOI:10.1002/1521-3757(20010917)113:18<3468::AID-ANGE3468>3.0.CO;2-V
DNA-Kondensation durch einen Fullerenvektor, abgebildet auf molekularer Ebene: Die kraftmikroskopische (AFM-) Analyse eines Gemischs aus Plasmid-DNA und DNA-Fulleren-Aggregat lieferte erste Erkenntnisse über den Transfektionsmechanismus bei Anwendung eines kohlenstoffhaltigen Vektors. Gezeigt sind die AFM-Bilder von pBR322-DNA ohne (links) und, teilweise kondensiert, in Gegenwart von Fulleren (rechts).
Co-reporter:Eiichi Nakamura Dr.;Seiji Mori Dr.
Angewandte Chemie 2000 Volume 112(Issue 21) pp:
Publication Date(Web):27 OCT 2000
DOI:10.1002/1521-3757(20001103)112:21<3902::AID-ANGE3902>3.0.CO;2-L
Organokupferreagentien sind in der Organischen Chemie die universellsten Synthesewerkzeuge für die nucleophile Übertragung harter Carbanionen auf elektrophile Kohlenstoffzentren. Es wurden schon viele Untersuchungen zu ihren Strukturen und Reaktionsmechanismen beschrieben; diese führten zu einem breiten Spektrum an Vorschlägen hinsichtlich des Mechanismus, die einander allerdings teilweise sogar widersprachen. Neuere theoretische und physikalische Methoden haben es möglich gemacht, aus dem gesammelten Wissen über die Organokupferchemie einige wenige mechanistische Grundprinzipien herauszuarbeiten. In diesem Beitrag wird zunächst ein Überblick über die allgemeinen Strukturmerkmale von Organokupferverbindungen und die früheren mechanistischen Überlegungen gegeben; anschließend werden die aktuellsten Vorstellungen präsentiert, die man durch quantenchemische Rechnungen auf hohem Niveau für drei typische Cupratreaktionen – die Carbocuprierung, die konjugierte Addition und die SN2-Alkylierung – erhalten hat. Die so erlangte einheitliche Sicht der nucleophilen Reaktivität von Organocupratclustern enthüllte, dass die Organocupratchemie ein kompliziertes Beispiel für molekulare Erkennung und supramolekulare Chemie ist, das Chemiker seit langer Zeit nutzen, ohne dies geahnt zu haben. Wir werden auch eine Erklärung dafür liefern, warum das Kupferatom unter den benachbarten Elementen im Periodensystem so einzigartig ist.
Co-reporter:Eiichi Nakamura Dr.;Hiroyuki Isobe Dr.;Naoki Tomita;Masaya Sawamura Dr.;Shigeki Jinno Dr.;Hiroto Okayama Dr.
Angewandte Chemie 2000 Volume 112(Issue 23) pp:
Publication Date(Web):30 NOV 2000
DOI:10.1002/1521-3757(20001201)112:23<4424::AID-ANGE4424>3.0.CO;2-Y
Co-reporter:Hiroyuki Isobe Dr.;Naoki Tomita;Jae Wook Lee Dr.;Hee-Joon Kim Dr.;Kimoon Kim Dr. Dr.
Angewandte Chemie 2000 Volume 112(Issue 23) pp:
Publication Date(Web):30 NOV 2000
DOI:10.1002/1521-3757(20001201)112:23<4427::AID-ANGE4427>3.0.CO;2-G
Co-reporter:Seiji Mori
Chemistry - A European Journal 1999 Volume 5(Issue 5) pp:
Publication Date(Web):23 APR 1999
DOI:10.1002/(SICI)1521-3765(19990503)5:5<1534::AID-CHEM1534>3.0.CO;2-V
The origin of the stereochemistry of the conjugate addition of a dimeric lithium cuprate (Me2CuLi)2 to 2-cyclohexenone has been revealed by theoretical calculations, which were compared with experimentally observed intermediates and transition states (such as the one shown here) of the rate- and stereochemistry-determining step of the reaction.
Co-reporter: Eiichi Nakamura;Dr. Shigeru Yamago;Satoshi Ejiri
Angewandte Chemie 1995 Volume 107(Issue 19) pp:
Publication Date(Web):21 JAN 2006
DOI:10.1002/ange.19951071930
Co-reporter:Koji Harano, Kosuke Minami, Eisei Noiri, Koji Okamoto and Eiichi Nakamura
Chemical Communications 2013 - vol. 49(Issue 34) pp:NaN3527-3527
Publication Date(Web):2013/03/13
DOI:10.1039/C3CC40752G
We prepared self-assembled vesicles comprising layers of fullerene, alkyl chains, triazole, oligo(ethylene oxide) chains, biotin and avidin molecules. High-resolution scanning electron microscopy using a superhydrophilic indium-tin oxide substrate was found to be useful for nanometer-level structural analysis of the vesicles and individual avidin molecules whose structures are difficult to analyze.
Co-reporter:Hayato Tsuji, Chikahiko Mitsui and Eiichi Nakamura
Chemical Communications 2014 - vol. 50(Issue 94) pp:NaN14872-14872
Publication Date(Web):2014/09/15
DOI:10.1039/C4CC05108D
The hydrogen/deuterium primary kinetic isotope effect provides useful information about the degradation mechanism of OLED host materials. Thus, replacement of labile C–H bonds in the host with C–D bonds increases the device lifetime by a factor of five without loss of efficiency, and replacement with C–C bonds by a factor of 22.5.
Co-reporter:Takahiko Ichiki, Yutaka Matsuo and Eiichi Nakamura
Chemical Communications 2013 - vol. 49(Issue 3) pp:NaN281-281
Publication Date(Web):2012/11/08
DOI:10.1039/C2CC36988E
A new type of acceptor–donor2 dyad system containing two magnesium porphyrin molecules and a fullerene molecule is much more stable than the magnesium porphyrin itself. When it is fabricated into a binary system using imidazole carboxylic acid as a linker to indium tin oxide, the molecule effects efficient photocurrent generation that surpasses the device using the corresponding zinc porphyrin.
Co-reporter:Xiaozhang Zhu, Hayato Tsuji, Aswani Yella, Anne-Sophie Chauvin, Michael Grätzel and Eiichi Nakamura
Chemical Communications 2013 - vol. 49(Issue 6) pp:NaN584-584
Publication Date(Web):2012/12/04
DOI:10.1039/C2CC37124C
We demonstrate that a carbon-bridged phenylenevinylene (CPV)-linked dye serves as a novel and efficient sensitizer for dye-sensitized solar cells. The cells show IPCE values of greater than 90%, PCEs of up to 7.12%, and high open circuit voltages reaching close to 0.8 V based on the iodide/triiodide electrolyte.
Co-reporter:Koji Harano, Ricardo Mizoguchi Gorgoll and Eiichi Nakamura
Chemical Communications 2013 - vol. 49(Issue 69) pp:NaN7631-7631
Publication Date(Web):2013/06/27
DOI:10.1039/C3CC44510K
Upon dissolution of R5C60−K+ in water, a robust spherical vesicle forms that binds aromatic molecules primarily in the interior of the fullerene bilayer, as illustrated by the complete quenching of the fluorescence of an aromatic fluorescent dye bound in the bilayer.
Co-reporter:Yutaka Matsuo, Ayako Ozu, Naoki Obata, Naoya Fukuda, Hideyuki Tanaka and Eiichi Nakamura
Chemical Communications 2012 - vol. 48(Issue 32) pp:NaN3880-3880
Publication Date(Web):2012/02/24
DOI:10.1039/C2CC30262D
A chemical model of deterioration of a bulk heterojunction organic solar cell containing a photooxidized product of 1,4-bis(dimethylphenylsilylmethyl)[60]fullerene suggests that molecular oxygen degrades device performance by two mechanisms.
Co-reporter:Tobias Gärtner, Naohiko Yoshikai, Maria Neumeier, Eiichi Nakamura and Ruth M. Gschwind
Chemical Communications 2010 - vol. 46(Issue 25) pp:NaN4626-4626
Publication Date(Web):2010/05/11
DOI:10.1039/C0CC00360C
NMR studies of 13C/12C isotopic patterns in Cu(III) intermediates and reaction products together with DFT calculations of possible reaction pathways indicate an intermolecular SN2 like substitution mechanism for ligand exchange reactions in square planar Cu(III) complexes, which is proposed to be slow compared to reductive elimination at synthetic conditions.
Co-reporter:Chang-Zhi Li, Yutaka Matsuo, Takaaki Niinomi, Yoshiharu Sato and Eiichi Nakamura
Chemical Communications 2010 - vol. 46(Issue 45) pp:NaN8584-8584
Publication Date(Web):2010/10/21
DOI:10.1039/C0CC03028G
Treatment of [60]fullerene with potassium methylnaphthalenide and excess C6F5CH2Br afforded 1,4-bis(pentafluorobenzyl)[60]fullerene, the study of which showed that there is a face-to-face interaction between [60]fullerene and a perfluoro aromatic ring, allowing the molecule to be utilized for high-performance organic photovoltaic devices.
Co-reporter:Yutaka Matsuo, Yoichiro Kuninobu, Shingo Ito, Masaya Sawamura and Eiichi Nakamura
Dalton Transactions 2014 - vol. 43(Issue 20) pp:NaN7412-7412
Publication Date(Web):2013/09/24
DOI:10.1039/C3DT52002A
Acylated buckyferrocene and ruthenocene, Fe(η5-C60Me5)(η5-C5H4COR) (R = Me, Ph, and CHCHPh) and Ru(η5-C60Me5)(η5-C5H4COR) (R = Me and Ph), were obtained by Friedel–Crafts acylation of the parent buckymetallocenes with the corresponding acid chlorides and aluminum chloride in carbon disulfide at ambient temperature. The electron withdrawing and sterically hindered nature of the acyl groups were revealed by X-ray crystallography, infrared spectroscopy and electrochemical measurements. The possibility of further derivatizing the acylated products was illustrated by the conversion of the acetyl buckyruthenocene into the corresponding hydroxy and acetoxy compounds Ru(η5-C60Me5)(η5-C5H4CH(OH)Me) and Ru(η5-C60Me5)(η5-C5H4CH(OAc)Me).
Co-reporter:Yunlong Guo, Chao Liu, Kento Inoue, Koji Harano, Hideyuki Tanaka and Eiichi Nakamura
Journal of Materials Chemistry A 2014 - vol. 2(Issue 34) pp:NaN13830-13830
Publication Date(Web):2014/06/20
DOI:10.1039/C4TA02976C
Significant enhancement in the power conversion efficiency of an organic–inorganic hybrid solar cell was achieved by the use of suitably doped poly(3-hexylthiophene-2,5-diyl) (P3HT) spin coated on a 99.5% void-free perovskite layer prepared on a TiOx electron-transporting layer. The 9.2% device efficiency with pristine P3HT was increased to 12.4%.
Co-reporter:Hayato Tsuji, Kosuke Sato, Yoshiharu Sato and Eiichi Nakamura
Journal of Materials Chemistry A 2009 - vol. 19(Issue 21) pp:NaN3366-3366
Publication Date(Web):2009/04/29
DOI:10.1039/B906197E
A benzo[b]phosphole sulfide derivative DBPSB was found to function as a new class of n-type amorphous organic material, which features high electron drift mobility and high thermal stability, and the utility of this compound was demonstrated in an organic light-emitting diode.
Co-reporter:Pirmin A. Ulmann, Hideyuki Tanaka, Yutaka Matsuo, Zuo Xiao, Iwao Soga and Eiichi Nakamura
Physical Chemistry Chemical Physics 2011 - vol. 13(Issue 47) pp:NaN21049-21049
Publication Date(Web):2011/10/21
DOI:10.1039/C1CP22886B
A [70]fullerene–benzodifuranone acceptor dyad synthesized by a Ag+-mediated coupling reaction was used to construct a thin-film organic solar cell. The fullerene and the benzodifuranone dye in the dyad have close-lying LUMO levels in the range of 3.7–3.9 eV, so that energy transfer from the dye to the fullerene can take place. A p–n heterojunction photovoltaic device consisting of a tetrabenzoporphyrin and a [70]fullerene–benzodifuranone dyad showed a weak but discernible contribution from light absorption of the dyad to the photocurrent under both a positive and a negative effective bias. These results indicate that the benzodifuranone moiety attached to the acceptor contributes to light-harvesting by energy transfer.
![2-Pyridinecarboxamide, N-[(2-methylphenyl)methyl]-](http://img.cochemist.com/ccimg/867400/867350-26-3.png)
![2-Pyridinecarboxamide, N-[(2-methylphenyl)methyl]-](http://img.cochemist.com/ccimg/867400/867350-26-3_b.png)
![Indeno[2,1-a]indene, 5,10-dihydro-5,5,10,10-tetraphenyl-](http://img.cochemist.com/ccimg/91900/91861-70-0.png)
![Indeno[2,1-a]indene, 5,10-dihydro-5,5,10,10-tetraphenyl-](http://img.cochemist.com/ccimg/91900/91861-70-0_b.png)
![Silane, trimethyl[(3E)-4-phenyl-3-buten-1-ynyl]-](http://img.cochemist.com/ccimg/42200/42134-52-1.png)
![Silane, trimethyl[(3E)-4-phenyl-3-buten-1-ynyl]-](http://img.cochemist.com/ccimg/42200/42134-52-1_b.png)
![Benzene, [(1R,4R)-4-methyl-2-cyclohexen-1-yl]-, rel-](http://img.cochemist.com/ccimg/400100/400091-78-3.png)
![Benzene, [(1R,4R)-4-methyl-2-cyclohexen-1-yl]-, rel-](http://img.cochemist.com/ccimg/400100/400091-78-3_b.png)
![Benzene, 1,3,5-trifluoro-2,4,6-tris[(4-pentylphenyl)ethynyl]-](http://img.cochemist.com/ccimg/744300/744250-93-9.png)
![Benzene, 1,3,5-trifluoro-2,4,6-tris[(4-pentylphenyl)ethynyl]-](http://img.cochemist.com/ccimg/744300/744250-93-9_b.png)
![Benzene, 1-fluoro-4-[(2E)-3-phenyl-2-propenyl]-](http://img.cochemist.com/ccimg/485900/485844-19-7.png)
![Benzene, 1-fluoro-4-[(2E)-3-phenyl-2-propenyl]-](http://img.cochemist.com/ccimg/485900/485844-19-7_b.png)
![1H-Indole, 1-[(4-methoxyphenyl)methyl]-2-phenyl-](http://img.cochemist.com/ccimg/665100/665034-12-8.png)
![1H-Indole, 1-[(4-methoxyphenyl)methyl]-2-phenyl-](http://img.cochemist.com/ccimg/665100/665034-12-8_b.png)
![1H-Indole, 1-[(4-methoxyphenyl)methyl]-](http://img.cochemist.com/ccimg/22100/22051-21-4.png)
![1H-Indole, 1-[(4-methoxyphenyl)methyl]-](http://img.cochemist.com/ccimg/22100/22051-21-4_b.png)
![Benzene, [(1R,4S)-4-methyl-2-cyclohexen-1-yl]-, rel-](http://img.cochemist.com/ccimg/400100/400091-82-9.png)
![Benzene, [(1R,4S)-4-methyl-2-cyclohexen-1-yl]-, rel-](http://img.cochemist.com/ccimg/400100/400091-82-9_b.png)
![8H-Acenaphtho[1,2-c]pyrrole, 3,4-dichloro-](http://img.cochemist.com/ccimg/188300/188240-51-9.png)
![8H-Acenaphtho[1,2-c]pyrrole, 3,4-dichloro-](http://img.cochemist.com/ccimg/188300/188240-51-9_b.png)
![PHOSPHINE, BIS[2-(DIPHENYLPHOSPHINO)PHENYL]PHENYL-](http://img.cochemist.com/ccimg/53200/53103-03-0.png)
![PHOSPHINE, BIS[2-(DIPHENYLPHOSPHINO)PHENYL]PHENYL-](http://img.cochemist.com/ccimg/53200/53103-03-0_b.png)
![BENZENEMETHANAMINE, 4-METHOXY-N-[2-[(TRIMETHYLSILYL)ETHYNYL]PHENYL]-](http://img.cochemist.com/ccimg/665100/665033-55-6.png)
![BENZENEMETHANAMINE, 4-METHOXY-N-[2-[(TRIMETHYLSILYL)ETHYNYL]PHENYL]-](http://img.cochemist.com/ccimg/665100/665033-55-6_b.png)
![2-PYRIDINECARBOXAMIDE, N-[(3-METHYLPHENYL)METHYL]-](http://img.cochemist.com/ccimg/867400/867350-27-4.png)
![2-PYRIDINECARBOXAMIDE, N-[(3-METHYLPHENYL)METHYL]-](http://img.cochemist.com/ccimg/867400/867350-27-4_b.png)
![Benzene, 1-bromo-2-[(4-methylphenyl)thio]-](http://img.cochemist.com/ccimg/15900/15861-49-1.png)
![Benzene, 1-bromo-2-[(4-methylphenyl)thio]-](http://img.cochemist.com/ccimg/15900/15861-49-1_b.png)
![BENZENE, 1,3,5-TRIFLUORO-2,4,6-TRIS[[4-(TRIFLUOROMETHYL)PHENYL]ETHYNYL]-](http://img.cochemist.com/ccimg/744300/744251-09-0.png)
![BENZENE, 1,3,5-TRIFLUORO-2,4,6-TRIS[[4-(TRIFLUOROMETHYL)PHENYL]ETHYNYL]-](http://img.cochemist.com/ccimg/744300/744251-09-0_b.png)
![Methanone, bis[2-(diphenylphosphino)phenyl]-](/data/chemimg/2291200/845821-92-3.png)
![Methanone, bis[2-(diphenylphosphino)phenyl]-](/data/chemimg/2291200/845821-92-3_b.png)
![Benzene, [(1-methyl-2-propenyl)oxy]-](http://img.cochemist.com/ccimg/22600/22509-78-0.png)
![Benzene, [(1-methyl-2-propenyl)oxy]-](http://img.cochemist.com/ccimg/22600/22509-78-0_b.png)
![Benzene, 1-methyl-2-[(2E)-3-phenyl-2-propenyl]-](http://img.cochemist.com/ccimg/19000/18916-11-5.png)
![Benzene, 1-methyl-2-[(2E)-3-phenyl-2-propenyl]-](http://img.cochemist.com/ccimg/19000/18916-11-5_b.png)
![Ethanone, 1-[2-(diphenylphosphino)phenyl]-](/data/chemimg/2115700/50777-63-4.png)
![Ethanone, 1-[2-(diphenylphosphino)phenyl]-](/data/chemimg/2115700/50777-63-4_b.png)
![Hexanoic acid, 6-[[(4-methylphenyl)sulfonyl]oxy]-, ethyl ester](http://img.cochemist.com/ccimg/122900/122822-50-8.png)
![Hexanoic acid, 6-[[(4-methylphenyl)sulfonyl]oxy]-, ethyl ester](http://img.cochemist.com/ccimg/122900/122822-50-8_b.png)
](http://img.cochemist.com/ccimg/27000/26913-06-4.png)
](http://img.cochemist.com/ccimg/27000/26913-06-4_b.png)
![Benzene,1,1'-[thiobis(methylene)]bis[4-methyl-](http://img.cochemist.com/ccimg/13300/13250-88-9.png)
![Benzene,1,1'-[thiobis(methylene)]bis[4-methyl-](http://img.cochemist.com/ccimg/13300/13250-88-9_b.png)
![Zinc, [5,10,15,20-tetraphenyl-21H,23H-porphinato(2-)-κN21,κN22,κN23,κN24]-, (SP-4-1)-](/data/chemimg/478800/14074-80-7.png)
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