Co-reporter:Constance R. Pfeiffer;Naomi Biggins;William Lewis
CrystEngComm (1999-Present) 2017 vol. 19(Issue 37) pp:5558-5564
Publication Date(Web):2017/09/28
DOI:10.1039/C7CE00956A
When Ni(NO3)2·6H2O and N,N′-di(4-pyridyl)-1,4,5,8-naphthalenetetracarboxydiimide (DPNDI) are reacted, a one-dimensional coordination polymer (1) is formed. However, analogous reactions with either terephthalic acid (2) or 2,6-naphthalenedicarboxylic acid (3) and DPNDI affords two-dimensional, pillared metal–organic frameworks. 2 and 3 contain rectangular voids of different dimensions which are dictated by the carboxylate ligand and the arrangement of the {[M(k2-O2NO)]2(μ2-O2CR)2} secondary building unit (SBU) that forms the nodes of the framework. The role of SBU geometry, intermolecular face-to-face π–π and lone pair–π interactions involving the DPNDI ligands are discussed.
Co-reporter:Rahul Banerjee
CrystEngComm (1999-Present) 2017 vol. 19(Issue 33) pp:4866-4867
Publication Date(Web):2017/08/21
DOI:10.1039/C7CE90115A
A graphical abstract is available for this content
Co-reporter:Kunal S. Mali;Nicholas Pearce;Steven De Feyter
Chemical Society Reviews 2017 vol. 46(Issue 9) pp:2520-2542
Publication Date(Web):2017/05/09
DOI:10.1039/C7CS00113D
The application of supramolecular chemistry on solid surfaces represents an exciting field of research that continues to develop in new and unexpected directions. This review highlights recent advances in the field which range from the fundamental aspects of the thermodynamics of self-assembly through to the development of new materials with potential application as new materials. The unique aspects of working on solid surfaces are highlighted and advances in the assembly of many component systems and highly complex fractal-like and quasicrystalline systems discussed. The unique features of working in the surface-based environment and the utilisation of scanning probe microscopies as a primary characterisation tool are highlighted.
Co-reporter:Andrea Laybourn;Juliano Katrib;Rebecca S. Ferrari-John;Christopher G. Morris;Sihai Yang;Ofonime Udoudo;Timothy L. Easun;Chris Dodds;Samuel W. Kingman;Martin Schröder
Journal of Materials Chemistry A 2017 vol. 5(Issue 16) pp:7333-7338
Publication Date(Web):2017/04/18
DOI:10.1039/C7TA01493G
Synthesis of metal–organic framework (MOF) materials via microwave heating often involves shorter reaction times and offers enhanced control of particle size compared to conventional heating. However, there is little understanding of the interactions between electromagnetic waves and MOFs, their reactants, and intermediates, all of which are required for successful scale-up to enable production of commercially viable quantities of material. By examining the effect of average absorbed power with a constant total absorbed energy to prepare MIL-53(Al) we have defined a selective heating mechanism that affords control over MOF particle size range and morphology by altering the microwave power. This is the first time a selective mechanism has been established for the preparation of MOFs via microwave heating. This approach has been applied to the very rapid preparation of MIL-53(Al)ta (62 mg in 4.3 seconds) which represents the fastest reported synthesis of a MOF on this scale to date.
Co-reporter:Constance R. Pfeiffer;Nicholas Pearce
Chemical Communications 2017 vol. 53(Issue 84) pp:11528-11539
Publication Date(Web):2017/10/19
DOI:10.1039/C7CC06110B
The self-assembly of supramolecular arrays at solid surfaces is discussed with an emphasis on the degree of complexity that can be generated in such structures. The preparation of multi-component arrays is reviewed illustrating the approaches to generating many-component networks and the challenges that are encountered. The complexity of quasicrystalline and fractal molecular structures is also demonstrated along with recent developments in the synthesis of complexity perpendicular to the solid substrate through the formation of bilayer structures. Overall the importance of characterisation by scanning probe microscopy is evident in determining the complexity of structures at the molecular level.
Co-reporter:Ben A. Llewellyn, E. Stephen Davies, Constance R. Pfeiffer, Mick Cooper, William Lewis and Neil R. Champness
Chemical Communications 2016 vol. 52(Issue 10) pp:2099-2102
Publication Date(Web):15 Dec 2015
DOI:10.1039/C5CC09962E
A synthetic strategy involving a combination of tetra-thionation and amine substitution in the bay region of a perylene diimide (PDI) leads to remarkable examples of neutral PDIs with intense absorption maxima in the near infrared. Generation of the corresponding monoanions red shifts the absorption profile to give short-wavelength infrared bands.
Co-reporter:Anna G. Slater, Ya Hu, Lixu Yang, Stephen P. Argent, William Lewis, Matthew O. Blunt and Neil R. Champness
Chemical Science 2015 vol. 6(Issue 2) pp:1562-1569
Publication Date(Web):11 Dec 2014
DOI:10.1039/C4SC03531C
The synthesis and surface-based self-assembly of thymine-functionalised porphyrins is described. Reaction of 1-formylphenyl-3-benzoyl-thymine with suitable pyrollic species leads to the formation of tetra-(phenylthymine)porphyrin (tetra-TP) or mono-thymine-tri-(3,5-di-tert-butylphenyl)porphyrin (mono-TP). Single crystal X-ray diffraction studies demonstrate the self-association of mono-TP in the solid state through thymine⋯thymine hydrogen-bonding interactions but in solution this interaction (Kd = 6.1 ± 3.0 M−1) is relatively weak in comparison to the heteromolecular interaction between mono-TP and 9-propyladenine (K = 91.8 ± 20.5 M−1). STM studies of the tetratopic hydrogen-bonding tecton, tetra-TP, deposited on an HOPG substrate reveal the formation of an almost perfectly square self-assembled lattice through thymine⋯thymine hydrogen-bonding. Co-deposition of tetra-TP with 9-propyladenine leads to the adoption of preferable thymine⋯adenine interactions leading to the formation of a heteromolecular tetra-TP⋯9-propyladenine hydrogen bonded array including both Watson–Crick thymine⋯adenine interactions and adenine⋯adenine hydrogen-bonding. The studies demonstrate a pathway for the self-assembly of tetratopic hydrogen-bonding tectons and the use of preferential heteromolecular thymine⋯adenine interactions for the disruption of the homomolecular tetra-TP array. Studies of the self-assembly of tetra-TP and 9-propyladenine demonstrate a strong dependence on overall concentration and molar ratio of components indicating the importance of kinetic effects in surface self-assembly processes.
Co-reporter:Dr. Witold M. Bloch; Neil R. Champness; Christian J. Doonan
Angewandte Chemie 2015 Volume 127( Issue 44) pp:13052-13059
Publication Date(Web):
DOI:10.1002/ange.201501545
Abstract
Materialien mit offenen Gerüsten wurden hinsichtlich ihrer Fähigkeiten zur Gasspeicherung und -trennung umfassend untersucht, doch ihre hochkristalline Struktur kann auch genutzt werden, um Gastmoleküle und nicht zur Struktur gehörende Atome (nichtstrukturelle Atome) periodisch anzuordnen. Somit kann ein solches offenes Gerüst als Matrix zur Isolierung dieser Einheiten und zur Aufklärung ihrer Struktur durch Röntgenbeugung dienen. Diese Analysenmethode könnte hilfreich sein, wenn die Herstellung eines Einkristalls problematisch ist oder um Einblick in reaktive Verbindungen zu gewinnen, die im porösen Gitter stabilisiert werden können. Allerdings hat die Methode Grenzen, und bisher wurde keine allgemeingültige experimentelle Vorgehensweise entwickelt. Im Folgenden werden Beispiele vorgestellt, in denen Gerüstmaterialien verwendet wurden, um Moleküle für die Analyse durch Röntgenbeugung anzuordnen, und mögliche künftige Anwendungen diskutiert.
Co-reporter:Dr. Witold M. Bloch; Neil R. Champness; Christian J. Doonan
Angewandte Chemie International Edition 2015 Volume 54( Issue 44) pp:12860-12867
Publication Date(Web):
DOI:10.1002/anie.201501545
Abstract
Open-framework materials, such as metal–organic frameworks (MOFs) and coordination polymers have been widely investigated for their gas adsorption and separation properties. However, recent studies have demonstrated that their highly crystalline structures can be used to periodically organize guest molecules and non-structural metal compounds either within their pore voids or by anchoring to their framework architecture. Accordingly, the open framework can act as a matrix for isolating and elucidating the structures of these moieties by X-ray diffraction. This concept has broad scope for development as an analytical tool where obtaining single crystals of a target molecule presents a significant challenge and it additionally offers potential for obtaining insights into chemically reactive species that can be stabilized within the pore network. However, the technique does have limitations and as yet a general experimental method has not been realized. Herein we focus on recent examples in which framework materials have been utilized as a scaffold for ordering molecules for analysis by diffraction methods and canvass areas for future exploration.
Co-reporter:Anna G. Slater, Luis M. A. Perdigão, Peter H. Beton, and Neil R. Champness
Accounts of Chemical Research 2014 Volume 47(Issue 12) pp:3417
Publication Date(Web):October 20, 2014
DOI:10.1021/ar5001378
The arrangement of molecular species into extended structures remains the focus of much current chemical science. The organization of molecules on surfaces using intermolecular interactions has been studied to a lesser degree than solution or solid-state systems, and unanticipated observations still lie in store. Intermolecular hydrogen bonds are an attractive tool that can be used to facilitate the self-assembly of an extended structure through the careful design of target building blocks.Our studies have focused on the use of 3,4,9,10-perylene tetracarboxylic acid diimides (PTCDIs), and related functionalized analogues, to prepare extended arrays on surfaces. These molecules are ideal for such studies because they are specifically designed to interact with appropriate diaminopyridine-functionalized molecules, and related species, through complementary hydrogen bonds. Additionally, PTCDI species can be functionalized in the bay region of the molecule, facilitating modification of the self-assembled structures that can be prepared. Through a combination of PTCDI derivatives, sometimes in combination with melamine, porous two-dimensional arrays can be formed that can entrap guest molecules. The factors that govern the self-assembly processes of PTCDI derivatives are discussed, and the ability to construct suitable target arrays and host-specific molecular species, including fullerenes and transition metal clusters, is demonstrated.
Co-reporter:Timothy L. Easun, Junhua Jia, Thomas J. Reade, Xue-Zhong Sun, E. Stephen Davies, Alexander J. Blake, Michael W. George and Neil R. Champness
Chemical Science 2014 vol. 5(Issue 2) pp:539-544
Publication Date(Web):06 Dec 2013
DOI:10.1039/C3SC52745J
A metal-bearing coordination network synthesised from Re(2,2′-bipyridine-5,5′-dicarboxylate)(CO)3Cl bridging ligands and Cu(II) nodes, [{Cu(DMF)(H2O)[LRe(CO)3Cl]}·DMF]∞ReCu, undergoes an irreversible photoinduced charge transfer process. We demonstrate using time-resolved IR spectroscopy the nature of this photoinduced process and how, under suitable conditions, it is possible to initiate irreversible modification of the crystal through induction of the charge transfer process. As a result we are able to use the photoinduced process, which arises purely as a result of the structure of the coordination network, to write on crystals.
Co-reporter:Timothy L. Easun, Junhua Jia, James A. Calladine, Danielle L. Blackmore, Christopher S. Stapleton, Khuong Q. Vuong, Neil R. Champness, and Michael W. George
Inorganic Chemistry 2014 Volume 53(Issue 5) pp:2606-2612
Publication Date(Web):February 11, 2014
DOI:10.1021/ic402955e
The mechanism and intermediates in the UV-light-initiated ligand rearrangement of fac-Re(diimine)(CO)3Cl to form the mer isomer, when incorporated into a 3D metal–organic framework (MOF), have been investigated. The structure hosting the rhenium diimine complex is a 3D network with the formula {Mn(DMF)2[LRe(CO)3Cl]}∞ (ReMn; DMF = N,N-dimethylformamide), where the diimine ligand L, 2,2′-bipyridine-5,5′-dicarboxylate, acts as a strut of the MOF. The incorporation of ReMn into a KBr disk allows spatial distribution of the mer-isomer photoproduct in the disk to be mapped and spectroscopically characterized by both Fourier transform infrared and Raman microscopy. Photoisomerization has been monitored by IR spectroscopy and proceeds via dissociation of a CO to form more than one dicarbonyl intermediate. The dicarbonyl species are stable in the solid state at 200 K. The photodissociated CO ligand appears to be trapped within the crystal lattice and, upon warming above 200 K, readily recombines with the dicarbonyl intermediates to form both the fac-Re(diimine)(CO)3Cl starting material and the mer-Re(diimine)(CO)3Cl photoproduct. Experiments over a range of temperatures (265–285 K) allow estimates of the activation enthalpy of recombination for each process of ca. 16 (±6) kJ mol–1 (mer formation) and 23 (±4) kJ mol–1 (fac formation) within the MOF. We have compared the photochemistry of the ReMn MOF with a related alkane-soluble Re(dnb)(CO)3Cl complex (dnb = 4,4′-dinonyl-2,2′-bipyridine). Time-resolved IR measurements clearly show that, in an alkane solution, the photoinduced dicarbonyl species again recombines with CO to both re-form the fac-isomer starting material and form the mer-isomer photoproduct. Density functional theory calculations of the possible dicarbonyl species aids the assignment of the experimental data in that the ν(CO) IR bands of the CO loss intermediate are, as expected, shifted to lower energy when the metal is bound to DMF rather than to an alkane and both solution data and calculations suggest that the ν(CO) band positions in the photoproduced dicarbonyl intermediates of ReMn are consistent with DMF binding.
Co-reporter:Ben A. Llewellyn, Anna G. Slater, Gudrun Goretzki, Timothy L. Easun, Xue-Zhong Sun, E. Stephen Davies, Stephen P. Argent, William Lewis, Andrew Beeby, Michael W. George and Neil R. Champness
Dalton Transactions 2014 vol. 43(Issue 1) pp:85-94
Publication Date(Web):27 Sep 2013
DOI:10.1039/C3DT50874A
The synthesis and photophysical study of a perylene diimide (PDI) functionalised with platinum acetylide units of the type, trans{–CC–Pt(PBu3)2–CC–Ph} and comparison with a phenylacetylide substituted model compound are reported. The model compound demonstrates typical perylene absorption and photoluminescence spectra characteristic of singlet excited state formation and decay. The Pt-substitution, however, appears to induce spin–orbit coupling into the chromophore and giving rise to a triplet excited state which was confirmed by transient absorption measurements. This excited state is quenched by oxygen, leading to the formation of singlet oxygen in dichloromethane, recorded by time-resolved near-infrared luminescence measurements.
Co-reporter:David R. Allan;Daniel Bailey;Nigel Bird;Alexer J. Blake, ;Deguang Huang;Conal P. Keane;Jonathan McMaster;Timothy J. Prior;Jeremiah P. Tidey ;Martin Schröder
Acta Crystallographica Section B 2014 Volume 70( Issue 3) pp:469-486
Publication Date(Web):
DOI:10.1107/S2052520614008786
The mononuclear macrocyclic PdII complex cis-[PdCl2([9]aneS3)] ([9]aneS3 = 1,4,7-trithiacyclo-nonane) converts at 44 kbar into an intensely coloured chain polymer exhibiting distorted octahedral coordination at the metal centre and an unprecedented [1233] conformation for the thioether ligand. The evolution of an intramolecular axial sulfur–metal interaction and an intermolecular equatorial sulfur–metal interaction is central to these changes. High-pressure crystallographic experiments have also been undertaken on the related complexes [PtCl2([9]aneS3)], [PdBr2([9]aneS3)], [PtBr2([9]aneS3)], [PdI2([9]aneS3)] and [PtI2([9]aneS3)] in order to establish the effects of changing the halide ligands and the metal centre on the behaviour of these complexes under pressure. While all complexes undergo contraction of the various interaction distances with increasing pressure, only [PdCl2([9]aneS3)] undergoes a phase change. Pressure-induced I...I interactions were observed for [PdI2([9]aneS3)] and [PtI2([9]aneS3)] at 19 kbar, but the corresponding Br...Br interactions in [PdBr2([9]aneS3)] and [PtBr2([9]aneS3)] only become significant at much higher pressure (58 kbar). Accompanying density functional theory (DFT) calculations have yielded interaction energies and bond orders for the sulfur–metal interactions.
Co-reporter:Neil R. Champness
Chemical Communications 2013 vol. 49(Issue 4) pp:331-333
Publication Date(Web):29 Oct 2012
DOI:10.1039/C2CC36098E
In 1994 the field of coordination frameworks was still in its infancy and yet to give birth to its offspring research field of metal–organic frameworks (MOFs). Studies by Zaworotko and Ciani served to illustrate both the simplicity and the complexity of these remarkable structures.
Co-reporter:Victoria J. Richards, Alexander J. Blake, William Lewis, Harriott Nowell, Christopher D. J. Parmenter and Neil R. Champness
CrystEngComm 2013 vol. 15(Issue 45) pp:9704-9712
Publication Date(Web):14 Aug 2013
DOI:10.1039/C3CE41082J
The reaction of a bis-imidazole ligand, N,N′-bis(3-(1-imidazolyl)propyl)-1,4,5,8-naphthalene-tetracarboxylicdiimide (BIPNDI), with either Mn(NO3)2 or Cu(NO3)2 affords coordination polymers of formula {[Mn(BIPNDI)3](NO3)2}∞ or [M(BIPNDI)2(NO3)2]∞ (M = Mn or Cu). Single crystal X-ray diffraction studies confirm the structures of supramolecular isomers of {[Mn(BIPNDI)3](NO3)2}∞ (1,2), both of which contain two-dimensional coordination polymer sheets, and a one-dimensional coordination polymer [Mn(BIPNDI)2(NO3)2]∞ (3). Reaction of either Mn(NO3)2 or Cu(NO3)2 with BIPNDI exploiting rapid precipitation affords sub-micron coordination particles of either rod-shaped (4, Mn) or spherical (5, Cu) morphology depending on the metal salt used. SEM and DLS studies were used to probe the morphology and solution behaviour of the coordination particles. Spectroscopic investigations indicate that the rod-shaped, Mn-based particles comprise two-dimensional coordination polymers in contrast to the spherical, Cu-based particles which are composed of one-dimensional coordination polymers.
Co-reporter:Anna G. Slater, E. Stephen Davies, Stephen P. Argent, William Lewis, Alexander J. Blake, Jonathan McMaster, and Neil R. Champness
The Journal of Organic Chemistry 2013 Volume 78(Issue 7) pp:2853-2862
Publication Date(Web):March 18, 2013
DOI:10.1021/jo400026r
The synthesis and separation of the 1,6- and 1,7- isomers of N,N′-bis(alkyl)diadamantylthio-3,4,9,10-perylenetetracarboxylic acid diimide are reported. Investigations of the structural, electrochemical, spectroscopic, and spectroelectrochemical properties of the isomers reveal a sequence of electrochemically and chemically reversible reduction processes for both isomers. Three X-ray crystal structures are reported including a pair of 1,6- and 1,7-isomers demonstrating the twist of the perylene core in the solid state. Our studies thoroughly characterize the mono- and direduced states of the two isomers allowing unequivocal characterization of the reduced species by UV–vis and IR spectroscopic measurements. EPR studies also allow direct identification of the monoreduced PTCDI species and spectroscopic measurements confirm the delocalization of electronic density around the carbonyl moieties of the reduced species.
Co-reporter:Minna T. Räisänen, Anna G. Slater (née Phillips), Neil R. Champness and Manfred Buck
Chemical Science 2012 vol. 3(Issue 1) pp:84-92
Publication Date(Web):04 Oct 2011
DOI:10.1039/C1SC00543J
1,7-Diadamantanethioperylene-3,4:9,10-tetracarboxylic diimide, (Ad-S)2–PTCDI, adsorbed on Au(111) from solution was investigated by scanning tunneling microscopy (STM) and X-ray photoelectron spectroscopy (XPS). (Ad-S)2–PTCDI forms a well-ordered monolayer whose structure is described by a (2√63 × √19)R19.1° chiral unit cell containing four molecules. Codeposition of (Ad-S)2–PTCDI with 1,3,5-triazine-2,4,6-triamine (melamine) yields a honeycomb network whose (7√3 × 7√3)R30° unit cell is identical to the unsubstituted PTCDI/melamine analogue. The effect of the adamantyl thioether moieties on the adsorption of guest molecules is investigated using adamantane thiol and C60. While the thioether units do not affect the packing of adamantane thiol molecules a pronounced influence is seen in the case of fullerene. Pore modification involving different combinations of enantiomers of (Ad-S)2–PTCDI give rise to distinctly different arrangements of C60 molecules. The diversity of patterns is further increased by the presence of unsubstituted PTCDI molecules.
Co-reporter:Victoria J. Richards, Alexandra L. Gower, Jasper E. H. B. Smith, E. Stephen Davies, Dorothée Lahaye, Anna G. Slater, William Lewis, Alexander J. Blake, Neil R. Champness and Deborah L. Kays
Chemical Communications 2012 vol. 48(Issue 12) pp:1751-1753
Publication Date(Web):03 Jan 2012
DOI:10.1039/C2CC16047A
The redox processes associated with BODIPY analogues are studied by electrochemical and spectroscopic methods revealing a characteristic profile for the persistent BODIPY radical and quenching of fluorescence upon reduction.
Co-reporter:Victoria J. Richards, Stephen P. Argent, Adam Kewley, Alexander J. Blake, William Lewis and Neil R. Champness
Dalton Transactions 2012 vol. 41(Issue 14) pp:4020-4026
Publication Date(Web):03 Feb 2012
DOI:10.1039/C2DT12055K
Five new metal–organic frameworks prepared from the ligand 5-bis(3-(1-imidazolyl)propylcarbamoyl)terephthalate (bipta2−) and transition metal salts, Zn2+ (1), Co2+ (2), Mn2+ (3, 4) and Cu2+ (5), are reported. Single crystal X-ray studies reveal that the bipta2− ligand acts as a tetradentate ligand and combines with four-coordinate cationic metal nodes to give four-connected framework structures. Whilst reaction of bipta2− with Zn(II) gives rise to a framework of diamondoid topology 1, the analogous frameworks with Co(II), Mn(II) and Cu(II) afford frameworks that incorporate square-planar nodes. Whereas 2 and 5 form frameworks of Cd(SO4) (cds) and square 44 nets (sql), respectively, reaction of Mn(II) with bipta2− forms two supramolecular isomers of topology cds for 3 and sql for 4.
Co-reporter:Stephen P. Argent ; Alex Greenaway ; Maria del Carmen Gimenez-Lopez ; William Lewis ; Harriott Nowell ; Andrei N. Khlobystov ; Alexander J. Blake ; Neil R. Champness ;Martin Schröder
Journal of the American Chemical Society 2011 Volume 134(Issue 1) pp:55-58
Publication Date(Web):November 23, 2011
DOI:10.1021/ja207845u
Reaction of H3L with Cd(NO3)2·4H2O in DMF at 150 °C for 3 days affords the metal–organic nanosphere [Cd66(μ3-OH)28(μ3-O)16(μ5-NO3-O,O,O′,O′,O″,O″)12(L)20(μ2-DMF)12⊂(DMF)9]. The cluster is composed of a spherical shell of 66 Cd(II) cations bridged by 28 μ3-hydroxide, 16 μ3-oxo, and five μ5-NO3– anions surrounded by a shell of 20 tripodal capping ligands (L) and 12 DMF ligands. The 66 Cd(II) cations and 12 NO3– anions form a polydeltahedron that has 78 vertices [Cd(II) or NO3–] (V), 228 edges (E), and 152 triangular faces (F), giving it an Euler characteristic (χ) of 2 (χ = V + F – E). Reaction of H3L with Cd(NO3)2·4H2O at lower temperatures or with CdCl2 affords coordination polymer frameworks instead of nanospheres.
Co-reporter:Anna G. Slater (née Phillips), Peter H. Beton and Neil R. Champness
Chemical Science 2011 vol. 2(Issue 8) pp:1440-1448
Publication Date(Web):13 Jun 2011
DOI:10.1039/C1SC00251A
Self-assembly of two-dimensional supramolecular arrays on surfaces represents a significant challenge to chemists, materials scientists and physicists. This article highlights advances in using supramolecular interactions, particularly hydrogen bonding, to self-assemble such two-dimensional arrays on surfaces. Scanning-probe microscopies, particularly scanning tunnelling microscopy (STM), can be used to determine the precise molecular arrangement of the self-assembled structures allowing insight into the self-assembly process at the molecular level. The use of such supramolecular assemblies to trap guest species, mimicking host–guest chemistry in the solution phase, will also be discussed. Such images provide great insight into the advantages and restrictions of working in two dimensions in comparison to the solution phase or the solid state.
Co-reporter:Ilich A. Ibarra, Sihai Yang, Xiang Lin, Alexander J. Blake, Pierre J. Rizkallah, Harriott Nowell, David R. Allan, Neil R. Champness, Peter Hubberstey and Martin Schröder
Chemical Communications 2011 vol. 47(Issue 29) pp:8304-8306
Publication Date(Web):20 Jun 2011
DOI:10.1039/C1CC11168J
The metal–organic frameworks NOTT-400 and NOTT-401, based on a binuclear [Sc2(μ2-OH)(O2CR)4] building block, have been synthesised and characterised; the desolvated framework NOTT-401a shows a BET surface area of 1514 m2 g−1 with a total H2 uptake of 4.44 wt% at 77 K and 20 bar.
Co-reporter:Chenrong Tan, Sihai Yang, Neil R. Champness, Xiang Lin, Alexander J. Blake, William Lewis and Martin Schröder
Chemical Communications 2011 vol. 47(Issue 15) pp:4487-4489
Publication Date(Web):11 Mar 2011
DOI:10.1039/C1CC10378D
The polyhedral complex [Cu4L(H2O)4]solv (NOTT-140) shows a 4,8-connected structure of rare scu topology comprising octahedral and cuboctahedral cages; desolvated NOTT-140a shows a total CO2 uptake of 314.6 cm3 (STP) cm−3 at 20 bar, 293 K, and a total H2 uptake of 6.0 wt% at 20 bar, 77 K.
Co-reporter:Sihai Yang, Gregory S. B. Martin, Jeremy J. Titman, Alexander J. Blake, David R. Allan, Neil R. Champness, and Martin Schröder
Inorganic Chemistry 2011 Volume 50(Issue 19) pp:9374-9384
Publication Date(Web):September 7, 2011
DOI:10.1021/ic200967b
Three isostructural anionic frameworks {[(Hdma)(H3O)][In2(L1)2]·4DMF·5H2O}∞ (NOTT-206-solv), {[H2ppz][In2(L2)2]·3.5DMF·5H2O}∞ (NOTT-200-solv), and {[H2ppz][In2(L3)2]·4DMF·5.5H2O}∞ (NOTT-208-solv) (dma = dimethylamine; ppz = piperazine) each featuring organic countercations that selectively block the channels and act as pore gates have been prepared. The organic cations within the as-synthesized frameworks can be replaced by Li+ ions to yield the corresponding Li+-containing frameworks {Li1.2(H3O)0.8[In2(L1)2]·14H2O}∞ (NOTT-207-solv), {Li1.5(H3O)0.5[In2(L2)2]·11H2O}∞ (NOTT-201-solv), and {Li1.4(H3O)0.6[In2(L3)2]·4acetone·11H2O}∞ (NOTT-209-solv) in which the pores are now unblocked. The desolvated framework materials NOTT-200a, NOTT-206a, and NOTT-208a display nonporous, hysteretic and reversible N2 uptakes, respectively, while NOTT-206a and NOTT-200a provide a strong kinetic trap showing adsorption/desorption hysteresis with H2. Single crystal X-ray analysis confirms that the Li+ ions are either tetrahedrally (in NOTT-201-solv and NOTT-209-solv) or octahedrally (in NOTT-207-solv) coordinated by carboxylate oxygen atoms and/or water molecules. This is supported by 7Li solid-state NMR spectroscopy. NOTT-209a, compared with NOTT-208a, shows a 31% enhancement in H2 storage capacity coupled to a 38% increase in the isosteric heat of adsorption to 12 kJ/mol at zero coverage. Thus, by modulating the pore environment via postsynthetic cation exchange, the gas adsorption properties of the resultant MOF can be fine-tuned. This affords a methodology for the development of high capacity storage materials that may operate at more ambient temperatures.
Co-reporter:Junhua Jia, Harprit Singh Athwal, Alexander J. Blake, Neil R. Champness, Peter Hubberstey and Martin Schröder
Dalton Transactions 2011 vol. 40(Issue 45) pp:12342-12349
Publication Date(Web):25 Oct 2011
DOI:10.1039/C1DT10901D
Reaction of Co(NO3)2·6H2O with H2L [H2L = pyridine-4-(phenyl-3′,5′-dicarboxylic acid)] under different reaction conditions gives three closely-related metal–organic framework polymers, {[Co2(L)2(DMF)]·n(solv)}∞ (1), {[Co(L)]·2DMF}∞ (2) and {[Co3(L)3(DMF)0.5(H2O)1.5]·n(solv)}∞ (3). Variation in reaction conditions thus has a decisive impact on the materials isolated, producing frameworks based upon either binuclear (1, 2) or trinuclear (3) cobalt cluster nodes. Analysis of their crystal structures shows that all three contain considerable solvent-accessible volumes, an indication of porosity that is confirmed for desolvated 1 and 3, which can store up to 2.75 and 2.33 wt% of H2 at 78 K and 20 bar, respectively.
Co-reporter:Nassiba Taleb, Victoria J. Richards, Stephen P. Argent, Joris van Slageren, William Lewis, Alexander J. Blake and Neil R. Champness
Dalton Transactions 2011 vol. 40(Issue 22) pp:5891-5894
Publication Date(Web):04 May 2011
DOI:10.1039/C1DT10057B
The synthesis, structural and magnetic characterisation of trinuclear manganese cluster, [Mn3O(O2C-anth)6(HOCH3)3] 1 (where O2C-anth = 9-anthracenecarboxylate), with crystallographic three-fold (C3) symmetry, are described. The cluster was prepared by a carboxylate exchange reaction between HO2C-anth and [Mn12O12(O2CMe)16(H2O)4] with concomitant fragmentation of the dodecanuclear Mn core of the starting material to form a trinuclear Mn3(μ3-O) cluster capped by six carboxylate ligands. Bond valence sum calculations and SQUID magnetometric measurements establish the oxidation states of the metal ions as MnII·2 MnIII which are antiferromagnetically coupled.
Co-reporter:Neil R. Champness
Dalton Transactions 2011 vol. 40(Issue 40) pp:10311-10315
Publication Date(Web):02 Sep 2011
DOI:10.1039/C1DT11184A
A personal perspective recognising the developments in the field of metal–organic frameworks, of where the challenges currently lie and the opportunities that are on the horizon.
Co-reporter:David J. Smith, Alexander J. Blake, Claire Wilson and Neil R. Champness
Dalton Transactions 2011 vol. 40(Issue 45) pp:12257-12264
Publication Date(Web):08 Sep 2011
DOI:10.1039/C1DT10815H
Three CuI complexes of diimine-bearing macrocyclic ligands are described. Reaction of CuI with macrocycles of different ring size gives rise to differing degrees of aggregation of (CuI)n in the solid state. X-Ray diffraction studies reveal that whereas macrocycles with smaller ring sizes give rise to simple mononuclear CuI diimine complexes, a macrocycle of larger ring size affords a dinuclear (CuI)2 moiety, encompassed within the ligand ring. Thus, the macrocycle can be seen to determine the extent of CuI aggregation in the solid state.
Co-reporter:Dr. Benjamin J. Slater;Dr. E. Stephen Davies;Dr. Stephen P. Argent;Dr. Harriott Nowell;Dr. William Lewis;Dr. Alexer J. Blake;Dr. Neil R. Champness
Chemistry - A European Journal 2011 Volume 17( Issue 52) pp:14746-14751
Publication Date(Web):
DOI:10.1002/chem.201103090
Abstract
The first example of a [2]-rotaxane in which a perylene diimide acts as a recognition site has been synthesised and characterised. The interlocked nature of the compound has been verified by both NMR studies and an X-ray structure determination. Electrochemical investigations confirm that the nature of the redox processes associated with the perylene diimide are modified by the complexation process and that it is possible to mono-reduce the [2]-rotaxane to give a radical anion based rotaxane. Further reduction of the compound leads to de-threading of the macrocycle from the reduced PTCDI recognition site. Our synthetic strategies confirm the potential of PTCDI-based rotaxanes as viable targets for the preparation of complex interlocked species.
Co-reporter:Dr. Thomas W. Chamberlain;Dr. E. Stephen Davies;Dr. Andrei N. Khlobystov; Neil R. Champness
Chemistry - A European Journal 2011 Volume 17( Issue 13) pp:3759-3767
Publication Date(Web):
DOI:10.1002/chem.201003092
Abstract
Fullerene (C60) and 3,4,9,10-perylene tetracarboxylic diimide (PTDCI) were used as building blocks for an electron acceptor dyad (C60–PTCDI) and triad (C60–PTCDI–C60). As the first reduction potentials for C60 and PTCDI are very close, simultaneous introduction of two or three electrons is possible into the dyad and triad, respectively. Further stepwise electrochemical reduction leads to formation of a series of well-defined anionic species in which electrons associated with the fullerene or the PTDCI components of the molecule can be clearly distinguished. In total, up to four electrons can be reversibly injected into the dyad C60–PTCDI and up to six into the triad C60–PTCDI–C60 system. The optical absorption properties in the UV/Vis range are also crucially defined by the distribution of electrons between the acceptor parts, as the injection/removal of electrons causes drastic colour changes in the dyad and the triad systems.
Co-reporter:Yong Yan;Dr. Alexer J. Blake;Dr. William Lewis;Dr. Sarah A. Barnett;Dr. Anne Dailly;Dr. Neil R. Champness;Dr. Martin Schröder
Chemistry - A European Journal 2011 Volume 17( Issue 40) pp:11162-11170
Publication Date(Web):
DOI:10.1002/chem.201101341
Abstract
Three isostructural metal–organic polyhedral cage based frameworks (denoted NOTT-113, NOTT-114 and NOTT-115) with (3,24)-connected topology have been synthesised by combining hexacarboxylate isophthalate linkers with {Cu2(RCOO)4} paddlewheels. All three frameworks have the same cuboctahedral cage structure constructed from 24 isophthalates from the ligands and 12 {Cu2(RCOO)4} paddlewheel moieties. The frameworks differ only in the functionality of the central core of the hexacarboxylate ligands with trimethylphenyl, phenylamine and triphenylamine moieties in NOTT-113, NOTT-114 and NOTT-115, respectively. Exchange of pore solvent with acetone followed by heating affords the corresponding desolvated framework materials, which show high BET surface areas of 2970, 3424 and 3394 m2 g−1 for NOTT-113, NOTT-114 and NOTT-115, respectively. Desolvated NOTT-113 and NOTT-114 show high total H2 adsorption capacities of 6.7 and 6.8 wt %, respectively, at 77 K and 60 bar. Desolvated NOTT-115 has a significantly higher total H2 uptake of 7.5 wt % under the same conditions. Analysis of the heats of adsorption (Qst) for H2 reveals that with a triphenylamine moiety in the cage wall, desolvated NOTT-115 shows the highest value of Qst for these three materials, indicating that functionalisation of the cage walls with more aromatic rings can enhance the H2/framework interactions. In contrast, measurement of Qst reveals that the amine-substituted trisalkynylbenzene core used in NOTT-114 gives a notably lower H2/framework binding energy.
Co-reporter:Yong Yan;Dr. Alexer J. Blake;Dr. William Lewis;Dr. Sarah A. Barnett;Dr. Anne Dailly;Dr. Neil R. Champness;Dr. Martin Schröder
Chemistry - A European Journal 2011 Volume 17( Issue 40) pp:
Publication Date(Web):
DOI:10.1002/chem.201190195
Co-reporter:Wenbin Yang ; Alex Greenaway ; Xiang Lin ; Ryotaro Matsuda ; Alexander J. Blake ; Claire Wilson ; William Lewis ; Peter Hubberstey ; Susumu Kitagawa ; Neil R. Champness ;Martin Schröder
Journal of the American Chemical Society 2010 Volume 132(Issue 41) pp:14457-14469
Publication Date(Web):September 24, 2010
DOI:10.1021/ja1042935
Reaction of β-amino-β-(pyrid-4-yl)acrylonitrile with the aromatic dicarboxaldehydes 9,10-bis(4-formylphenyl)anthracene and terephthalaldehyde affords the dihydropyridyl products 9,10-bis(4-((3,5-dicyano-2,6-dipyridyl)dihydropyridyl)phenyl)anthracene (L1) and 1,4-bis(4-(3,5-dicyano-2,6-dipyridyl)dihydropyridyl)benzene (L2), respectively. In the solid state [L1]·2.5DMF·3MeOH (SOF-1) crystallizes in the monoclinic space group P21/c and forms a 3D stable supramolecular organic framework via strong N−H···Npy hydrogen bonds and π−π interactions. The material incorporates pyridyl-decorated channels and shows permanent porosity in the solid state. The pore volumes of the desolvated framework SOF-1a calculated from the N2 isotherm at 125 K and the CO2 isotherm at 195 K are 0.227 and 0.244 cm3 g−1, respectively. The N2 absorption capacity of SOF-1a at 77 K is very low, with an uptake of 0.63 mmol g−1 at 1 bar, although saturation N2 adsorption at 125 K is 6.55 mmol g−1 (or 143 cm3 g−1). At ambient temperature, SOF-1a shows significant CO2 adsorption with approximately 3 mol of CO2 absorbed per mole of host at 16 bar and 298 K, corresponding to 69 cm3 g−1 at STP. SOF-1a also adsorbs significant amounts of C2H2, with an uptake of 124 cm3 (STP) g−1 (5.52 mmol g−1) at 1 bar at 195 K. Methane uptake at 195 K and 1 bar is 69 cm3 (STP) g−1. Overall, gas adsorption measurements on desolvated framework SOF-1a reveal not only high capacity uptakes for C2H2 and CO2, compared to other crystalline molecular organic solids, but also an adsorption selectivity in the order C2H2 > CO2 > CH4 > N2. Overall, C2H2(270 K)/CH4(273 K) selectivity is 33.7 based on Henry’s Law constant, while the C2H2(270 K)/CO2(273 K) ratio of uptake at 1 bar is 2.05. The less bulky analogue L2 crystallizes in the triclinic space group P1̅ as two different solvates [L2]·2DMF·5C6H6 (S2A) and [L2]·2DMF·4MeOH (S2B) as pale yellow tablets and blocks, respectively. Each L2 molecule in S2A participates in two N−H···O hydrogen bonds between dihydropyridyl rings and solvent DMF molecules. Packing of these layers generates 1D nanochannels along the crystallographic a and b axes which host DMF and benzene molecules. In S2B, each L2 ligand participates in hydrogen bonding via an N−H···O interaction between the N−H of the dihydropyridyl ring and the O of a MeOH and also via an N···H−O interaction between the N center of a pyridine ring and the H−O of a second MeOH molecule. The presence of the L2−HOMe hydrogen bonds prevents ligand−ligand hydrogen bonding. As a result, S2B crystallizes as one-dimensional chains rather than as an extended 3D network. Thermal removal of solvents from S2A results in conversion to denser phase S2C which shows no effective permanent porosity.
Co-reporter:Anna G. Phillips, Luís M. A. Perdigão, Peter H. Beton and Neil R. Champness
Chemical Communications 2010 vol. 46(Issue 16) pp:2775-2777
Publication Date(Web):25 Feb 2010
DOI:10.1039/B926824C
A unimolecular hydrogen-bonded network is formed by a perylene-diimide derivative following surface self-assembly leading to the formation of pores of appropriate dimensions to accommodate regularly spaced guest C60 molecules.
Co-reporter:AndrewJ. Pollard;EdwardW. Perkins Dr.;NicholasA. Smith;Alex Saywell;Gudrun Goretzki Dr.;AnnaG. Phillips;StephenP. Argent Dr.;Hermann Sachdev Priv.-Doz.;Frank Müller Dr.;Stefan Hüfner ;Stefan Gsell Dr.;Martin Fischer;Matthias Schreck Dr.;Jürg Osterwalder ;Thomas Greber ;Simon Berner Dr.;NeilR. Champness ;PeterH. Beton
Angewandte Chemie 2010 Volume 122( Issue 10) pp:1838-1843
Publication Date(Web):
DOI:10.1002/ange.200905503
Co-reporter:AndrewJ. Pollard;EdwardW. Perkins Dr.;NicholasA. Smith;Alex Saywell;Gudrun Goretzki Dr.;AnnaG. Phillips;StephenP. Argent Dr.;Hermann Sachdev Priv.-Doz.;Frank Müller Dr.;Stefan Hüfner ;Stefan Gsell Dr.;Martin Fischer;Matthias Schreck Dr.;Jürg Osterwalder ;Thomas Greber ;Simon Berner Dr.;NeilR. Champness ;PeterH. Beton
Angewandte Chemie International Edition 2010 Volume 49( Issue 10) pp:1794-1799
Publication Date(Web):
DOI:10.1002/anie.200905503
Co-reporter:Wenbin Yang ; Xiang Lin ; Alexander J. Blake ; Claire Wilson ; Peter Hubberstey ; Neil R. Champness ;Martin Schröder
Inorganic Chemistry 2009 Volume 48(Issue 23) pp:11067-11078
Publication Date(Web):October 30, 2009
DOI:10.1021/ic901429u
We have synthesized five new metal-organic coordination polymers incorporating the bent ligand H2hfipbb [4,4′-(hexafluoroisopropylidene)bis(benzoic acid)] with different transition metal ions and co-ligands via solvothermal reactions to give [Zn2(hfipbb)2(py)2]·DMF (1), [Zn2(hfipbb)2(4,4′-bipy)(H2O)] (2), [Zn2(hfipbb)2(bpdab)]·2DMF (3), [Cd2(hfipbb)2(DMF)2]·2DMF (4), and [Co(hfipbb)(dpp)]·MeOH (5) (py = pyridine, 4,4′-bipy = 4,4′-bipyridine, bpdab = 1,4-bis(4-pyridyl)-2,3-diaza-1,3-butadiene, dpp = 1,3-di(4-pyridyl)propane). Compound 1 displays a 2-fold 2D→2D parallel interpenetrated layer network with one-dimensional (1D) helical channels, while 3 exhibits a three-dimensional pillared helical-layer open framework of α-Po topology based upon binuclear paddlewheel units. In compounds 2 and 5, binuclear motifs with double carboxylate bridges are linked by hfipbb2− ligands into a 1D ribbon, which are further assembled into two-dimensional non-interpenetrated (4,4) layers via bipyridyl co-ligands. However, the different bridging modes of hfipbb2− ligands and the different disposition of the coordinated co-ligands around metal ions result in subtle differences in the final architecture. Thus, 2 is based on a binuclear cluster node, double-stranded hfipbb2− linkers, and single-stranded 4,4′-bipy linkers, while 5 is based on a binuclear cluster node and hfipbb2− and dpp linkers which are both double-stranded. Among these compounds, the Cd(II) complex 4 is possibly the most interesting because it represents a rare example in which metal centers are linked by carboxylate groups into infinite chains further joined together by hfipbb2− spacers to form a 2D network with tubular helical channels. All these coordination polymers exhibit low solvent-accessible volumes. Both 3 and 4 retain structural integrity and permanent microporosity upon evacuation of guest molecules, with hydrogen uptakes of 0.57 and 0.78 wt %, respectively, at 20 bar and 77 K.
Co-reporter:Gudrun Goretzki, E. Stephen Davies, Stephen P. Argent, John E. Warren, Alexander J. Blake and Neil R. Champness
Inorganic Chemistry 2009 Volume 48(Issue 21) pp:10264-10274
Publication Date(Web):October 2, 2009
DOI:10.1021/ic901379d
A series of multistate redox-active architectures has been synthesized, structurally characterized, and their optical and redox properties investigated. Specifically, two redox-active ferrocene or cobalt-dithiolene moieties have been introduced to the “bay” region of perylene-bisimides. Three of these disubstituted perylene-bisimide species have been structurally characterized by single crystal X-ray diffraction, confirming the twisted nature of the central perylene core. The first isomeric pair of disubstituted perylene-bisimide isomers, N,N′-di-(n-butyl)-1,7-diferrocenyl-perylene-3,4:9,10-tetracarboxylic acid bisimide (2) and N,N′-di-(n-butyl)-1,6-diferrocenyl-perylene-3,4:9,10-tetracarboxylic acid bisimide (3), structurally characterized by single crystal X-ray diffraction are reported and compared. Structural characterization of the cobalt-dithiolene substituted perylene-bisimide, N,N′-di-(n-butyl)-1,7-dicyclopentadienyl-cobalt(II)-dithiolenyl-perylene-3,4:9,10-tetracarboxylic acid bisimide (4), reveals the expected twisting of the perylene core and confirms the ene-dithiolate geometry of the cobalt dithiolene moiety. Cyclic voltammetry measurements, coupled with spectroelectrochemcial and electron paramagnetic resonance studies, of 1−4, where 1 is N,N′-di-(n-butyl)-1,7-diethynylferrocenyl-perylene-3,4:9,10-tetracarboxylic acid bisimide, reveal the two anticipated perylene-bisimide based reductions. In addition, for the ferrocene substituted compounds, 1−3, a single reversible two-electron oxidation is seen with only a small degree of communication between the ferrocene groups observed in the 1,6-isomer where the two ferrocene groups are attached to the same naphthyl moiety. In the case of 4, two reversible reductions associated with the cobalt-dithiolene moieties are observed, confirming communication across the reduced perylene core.
Co-reporter:Sławomir Bianketti, Alexander J. Blake, Claire Wilson, Peter Hubberstey, Neil R. Champness and Martin Schröder
CrystEngComm 2009 vol. 11(Issue 5) pp:763-769
Publication Date(Web):15 Jan 2009
DOI:10.1039/B813672F
A series of Cu(I) complexes of 4-mercaptopyridine (LH) are reported that form three-dimensional hydrogen-bonded frameworks in the solid-state. The 4-mercaptopyridine ligands co-ordinate to the Cu(I) cations via thiolate donors, leaving a pyridinium hydrogen-bond donor available for interaction with the relevant counter-anions. Four new Cu(I) complexes, [Cu2(LH)6]·2Cl 1, [Cu2(LH)6]·SiF6·2MeOH 2, [Cu4(LH)10]·4NO3·MeOH·H2O 3 and {[Cu6(LH)13]·2BF4·2SiF6·7.5MeOH}∞4 are reported and have been structurally characterised by single crystal X-ray diffraction. In each case hydrogen-bonded arrays are formed via N–H⋯anion hydrogen-bonds or by including hydrogen-bonding to guest solvent molecules. Whereas compound 1 adopts a rutile-like structure with [Cu2(LH)6]2+ and Cl− nodes adopting six- and three-connected arrangements, respectively, compounds 2 and 3 adopt six-connected nets of α-Po (41263) topology. Compound 4 forms a thiolate bridged co-ordination polymer constructed from repeating units of six Cu(I) centres connected by ten bridging and three terminal thiolate-bound LH donors, with complex hydrogen-bonding observed between the polymer cation and counter-anions.
Co-reporter:Wenbin Yang, Xiang Lin, Alexander J. Blake, Claire Wilson, Peter Hubberstey, Neil R. Champness and Martin Schröder
CrystEngComm 2009 vol. 11(Issue 1) pp:67-81
Publication Date(Web):14 Oct 2008
DOI:10.1039/B808496C
A series of metal–organic supramolecular co-ordination polymers [Zn(HPO4)(Hpytz)] (1), [Cd(Hpytz)2(H2PO4)2(H2O)2] (2), [Zn(pytz)2(H2O)4]·2H2O (3) [pytz− = 5-(4-pyridyl)tetrazolate], [M(tzpyo)2(H2O)4] [M = Zn (4), Ni (5)] [tzpyo− = 4-tetrazolate-pyridine N-oxide] incorporating tetrazolyl ligands have been synthesized via in situ [2 + 3] cycloaddition reactions of 4-cyanopyridine, 4-cyanopyridine N-oxide with sodium azide in the presence of zinc, cadmium or nickel salts under hydrothermal reaction conditions at 130–160 °C. Use of higher temperatures leads to hydrolysis of nitriles to carboxylates and subsequently to decarboxylation, resulting in two unexpected byproducts, [inaH]+(NO3−) (6) [ina = isonicotinic acid] and [(4,4′-bipyH2)(H2PO4)2(H2O)2] (7). Single crystal X-ray structure analyses of 1 and 2, prepared under hydrothermal conditions in the presence of H3PO4, reveal κ1-co-ordination of the N-donor at the 2-position of the tetrazolyl ligands binding in a TZ-mode. The pyridyl N-centres in 1 and 2 are protonated resulting in the formation of Npy–H⋯O hydrogen-bonds within the solid-state structures. In the absence of H3PO4 similar hydrothermal reactions afforded 3, in which the pyridyl group is directly bound to Zn(II) and tetrazolate-ring is unco-ordinated (PY-mode). Single crystal X-ray structures of 4 and 5 show a TZ-binding mode analogous to that for 1 and 2, with the pyridyl N-oxide moiety forming hydrogen-bonds with co-ordinated water molecules to give supramolecular pillar-layered frameworks. Complex 2 exhibits a distorted 6-connected α-Po net of 412·63 topology; 3 possesses an attractive 3D (4,5,10)-connected trinary (3·42·53)2(3·44·54·6)4(32·48·514.612·77·82) net, while the isostructural complexes 4 and 5 show 3D (4,8)-connected layer-pillared network structures with a unique (46)2(412·612·84) topology. In 6, all hydrogen atoms of inaH+ cations are involved in the formation of hydrogen-bonds with either nitrate or other inaH+ cations resulting in a 2D (4,6)-connected binary net with (32·42·52)(34·44·54·63) topology. In 7, the dihydrogenphosphate anions are arranged viahydrogen-bonds into an unusual (4,4) grid-type sheet, and these layers are further pillared by organobipyridine cations to form a 3D open framework with channels occupied by helical chains of water dimers. The thermal stability of these metal-tetrazolate complexes has been studied by TGA and powder X-ray diffraction, and the effect of proton source (H3PO4) on the co-ordination mode of these tetrazolyl ligands is discussed.
Co-reporter:NeilR. Champness Dr.
Angewandte Chemie International Edition 2009 Volume 48( Issue 13) pp:2274-2275
Publication Date(Web):
DOI:10.1002/anie.200806069
Co-reporter:Sihai Yang;Xiang Lin Dr.;Anne Dailly Dr.;AlexerJ. Blake Dr.;Peter Hubberstey Dr.;NeilR. Champness Dr.;Martin Schröder Dr.
Chemistry - A European Journal 2009 Volume 15( Issue 19) pp:4829-4835
Publication Date(Web):
DOI:10.1002/chem.200802292
Co-reporter:NeilR. Champness Dr.
Angewandte Chemie 2009 Volume 121( Issue 13) pp:2309-2310
Publication Date(Web):
DOI:10.1002/ange.200806069
Co-reporter:Christophe Silien, Manfred Buck, Gudrun Goretzki, Dorothée Lahaye, Neil R. Champness, Tobias Weidner and Michael Zharnikov
Langmuir 2009 Volume 25(Issue 2) pp:959-967
Publication Date(Web):December 23, 2008
DOI:10.1021/la802966s
Self-assembled monolayers (SAMs) of 3-(4-pyridine-4-yl-phenyl)-propane-1-thiol (PyP3) on Au(111)/mica have been studied by scanning tunneling microscopy (STM), polarization-modulated infrared reflection absorption spectroscopy (PM-IRRAS), high-resolution X-ray photoemission spectroscopy (HRXPS), and near-edge X-ray absorption fine structure (NEXAFS) spectroscopy. The quality of the SAM is found to be strongly dependent on the solvent. Substantial gold corrosion is observed if pure ethanol is used. In contrast, highly ordered and densely packed SAMs are formed from acetonitrile or a KOH/ethanol mixture. The structure is described by a 2√3 × √3 unit cell with the aromatic moiety oriented nearly perpendicular to the surface. The PyP3 films form with the pyridine moiety deprotonated. Variation of pH allows reversible protonation without measurable damage of the SAM.
Co-reporter:Wenbin Yang, Xiang Lin, Junhua Jia, Alexander J. Blake, Claire Wilson, Peter Hubberstey, Neil R. Champness and Martin Schröder
Chemical Communications 2008 (Issue 3) pp:359-361
Publication Date(Web):09 Nov 2007
DOI:10.1039/B712201B
A biporous three dimensional (3,6)-connected coordination framework is reported which exhibits excellent H2 adsorption at low pressures (≤1 bar) with high H2 adsorption density.
Co-reporter:Matthew Blunt, Xiang Lin, Maria del Carmen Gimenez-Lopez, Martin Schröder, Neil R. Champness and Peter H. Beton
Chemical Communications 2008 (Issue 20) pp:2304-2306
Publication Date(Web):08 Apr 2008
DOI:10.1039/B801267A
The use of a coronene guest template directs the formation of a 2D Kagomé network in preference to alternative close packed and parallel hydrogen-bonded structures of tetracarboxylic acid tectons self-assembled from solution on a graphite surface.
Co-reporter:Junhua Jia ; Alexander J. Blake ; Neil R. Champness ; Peter Hubberstey ; Claire Wilson ;Martin Schröder
Inorganic Chemistry 2008 Volume 47(Issue 19) pp:8652-8664
Publication Date(Web):August 29, 2008
DOI:10.1021/ic800422g
Reaction of 4,4′-bipyridine-N,N′-dioxide (L) with a variety of transition-metal salts in MeOH affords a range of coordination polymer products. For the complexes [FeCl3(μ-L)]∞, 1, and ([Cu(L)2(OHMe)2(μ-L)]·2PF6·n(solv))∞, 2, 1D chain structures are observed, whereas ([Mn(μ-L)3]·2ClO4)∞, 3, and ([Cu(μ-L)3]·2BF4)∞, 4, both show 2D sheet architectures incorporating an unusual 36-hxl topology. The more common 44-sql topology is observed in [Cd(ONO2)2(μ-L)2]∞, 5, ([Cu(OHMe)2(μ-L)2]·2ZrF5)∞, 6, ([Cu(L)2(μ-L)2]·2EF6)∞ (7 E = P; 8 E = Sb), and ([Et4N][Cu(OHMe)0.5(μ-L)2(μ-FSiF4F)0.5]·2SbF6·n(solv))∞, 9. In 6, the [ZrF5]− anion, formed in situ from [ZrF6]2−, forms 1D anionic chains ([ZrF5]−)∞ of vertex-linked octahedra, and these chains thread through a pair of inclined polycatenated ([Cu(OHMe)2(μ-L)2]2+)∞ 44-sql grids to give a rare example of a triply intertwined coordination polymer. 9 also shows a 3D matrix structure with 44-sql sheets of stoichiometry ([Cu(L)2]2+)∞ coordinatively linked by bridging [SiF6]2− anions to give a structure of 5-c 44.66-sqp topology. The mononuclear [Cu(L)6]·2BF4 (10) and [Cd(L)6]·2NO3 (11) and binuclear complexes [(Cu(L)(OH2))2(μ-L)2)]·2SiF6·n(solv), 12, are also reported. The majority of the coordination polymers are free of solvent and are nonporous. Thermal treatment of materials that do contain solvent results in structural disintegration of the complex structures giving no permanent porosity.
Co-reporter:Luís M.A. Perdigão Dr.;Alex Saywell;GiselleN. Fontes Dr.;PaulA. Staniec Dr.;Gudrun Goretzki Dr.;AnnaG. Phillips;NeilR. Champness ;PeterH. Beton
Chemistry - A European Journal 2008 Volume 14( Issue 25) pp:7600-7607
Publication Date(Web):
DOI:10.1002/chem.200800476
Abstract
Controlled self-assembly and chemical tailoring of bimolecular networks on surfaces is demonstrated using structural derivatives of 3,4:9,10-perylenetetracarboxylic diimide (PTCDI) combined with melamine (1,3,5-triazine-2,4,6-triamine). Two functionalised PTCDI derivatives have been synthesised, Br2–PTCDI and di(propylthio)–PTCDI, through attachment of chemical side groups to the perylene core. Self-assembled structures formed by these molecules on a Ag–Si(111)×R30° surface were studied with a room-temperature scanning tunneling microscope under ultrahigh vacuum conditions. It is shown that the introduction of side groups can have a significant effect upon both the structures formed, notably in the case of di(propylthio)–PTCDI which forms a previously unreported unimolecular hexagonal arrangement, and their entrapment behaviour. These results demonstrate a new route of functionalisation for network pores, opening up the possibility of designing nanostructured surface structures with chemical selectivity and applications in nanostructure templating.
Co-reporter:Juan P. Garrahan;Matthew O. Blunt;Xiang Lin;María del Carmen Giménez-López;James C. Russell;Martin Schröder;Peter H. Beton
Science 2008 Volume 322(Issue 5904) pp:1077-1081
Publication Date(Web):14 Nov 2008
DOI:10.1126/science.1163338
Abstract
A molecular network that exhibits critical correlations in the spatial order that is characteristic of a random, entropically stabilized, rhombus tiling is described. Specifically, we report a random tiling formed in a two-dimensional molecular network of p-terphenyl-3,5,3′,5′-tetracarboxylic acid adsorbed on graphite. The network is stabilized by hexagonal junctions of three, four, five, or six molecules and may be mapped onto a rhombus tiling in which an ordered array of vertices is embedded within a nonperiodic framework with spatial fluctuations in a local order characteristic of an entropically stabilized phase. We identified a topological defect that can propagate through the network, giving rise to a local reordering of molecular tiles and thus to transitions between quasi-degenerate local minima of a complex energy landscape. We draw parallels between the molecular tiling and dynamically arrested systems, such as glasses.
Co-reporter:Neil R. Champness
Dalton Transactions 2006 (Issue 7) pp:877-880
Publication Date(Web):30 Nov 2005
DOI:10.1039/B512638J
A personal perspective on the developing field of coordination frameworks, of where the challenges currently lie, where the field is heading and where the next breakthroughs will be made.
Co-reporter:Pamela V. Mason;Simon R. Collinson;Matthew G. Fisher;Gudrun Goretzki
European Journal of Organic Chemistry 2006 Volume 2006(Issue 6) pp:
Publication Date(Web):17 JAN 2006
DOI:10.1002/ejoc.200500628
The synthesis of bis(triazine) molecules capable of acting as synthetic receptors for barbiturate guest molecules is described. The binding properties are also reported illustrating the modulation of the binding properties of these species by the modification of the hydrogen-bonding patterns of the receptor molecule, namely 1,3-N,N′-bis[4-(dibenzylamino)-6-(butylamino)-1,3,5-triazin-2-yl]xylylenediamine (1). Thus 1,3-O,O′-bis[4-(dibenzylamino)-6-(butylamino)-1,3,5-triazin-2-yl]benzenedimethanol (3) and 1,3-O,O′-bis[4-(dibenzylamino)-6-(diethylamino)-1,3,5-triazin-2-yl]benzenedimethanol (5) have been prepared, and their binding constants compared to those observed for 1. In the case of compounds 3 and 5 the hydrogen-bonding secondary amines at the apex of the receptor 1 are substituted by non-hydrogen-bonding ether links. The hydrogen-bonding ability is further modified in the case of 5 by the removal of all hydrogen-bond donors from the receptor site, replacing secondary amines by tertiary amines. NMR binding studies illustrate how these simple modifications of the hydrogen-bonding patterns of these receptors influences the overall strength of binding demonstrating a simple mechanism for controlling host-guest complex formation. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Co-reporter:Frédéric Thébault, Alexander J. Blake, Claire Wilson, Neil R. Champness and Martin Schröder
New Journal of Chemistry 2006 vol. 30(Issue 10) pp:1498-1508
Publication Date(Web):15 Sep 2006
DOI:10.1039/B611561F
A family of ligands based upon the linking of two or three bis-(2-pyridyl)pyridazine (dppz) moieties via the 4- or 4,5-positions of the pyridazine rings has been synthesised using an inverse electron demand Diels–Alder pathway. Thus, reaction of 3,6-di(2-pyridyl)-1,2,4,5-tetrazine (dptz) with a series of dienes (1,4-divinylbenzene, 1,5-cyclooctadiene, norbornadiene, 1,5-hexadiene or 1,4-cyclohexadiene), diketones (1,4-diacetylbenzene), or trienes (trans,trans,cis-1,5,9-cyclododecatriene or trans,trans,trans-1,5,9-cyclododecatriene) has been studied and seven ligands isolated, namely 4,4′-(1,4-phenylene)bis(3,6-dipyridin-2-ylpyridazine) (L1), 5,6,11,12-tetrahydro-1,4,7,10-tetrapyridin-2-ylcycloocta[1,2-d:5,6-d′]dipyridazine (L2), 5,10-methano-1,4,6,9-tetrapyridin-2-ylpyridazino[4,5-g]phthalazine (L3), 4,4′-ethane-1,2-diylbis(3,6-dipyridin-2-ylpyridazine) (L4), 1,4,6,9-tetrapyridin-2-ylpyridazino[4,5-g]phthalazine (L5), cyclododeca[1,2-d:5,6-d′]dipyridazine-(11Z)-5,6,11,12,15,16-hexahydro-1,4,7,10-tetrapyridin-2-yl (L6) and 5,6,11,12,17,18-hexahydro-1,4,7,10,13,16-hexapyridin-2-ylcyclododeca[1,2-d:5,6-d′:9,10-d″]tripyridazine (L7). Compounds L1, L2 and L4 have been characterised by single crystal X-ray diffraction revealing the formation of molecular stacking in the solid-state via
π–π interactions between dppz moieties. The potential of these ligands to form multimetallic complexes has been demonstrated by the successful synthesis and structural characterisation of {[Cu4(L1)(NO3)6(MeO)2(MeOH)2]}, {[Cu4(L1)(NO3)6(MeO)2(EtOH)2]}, {[Cd(NO3)(EtOH)3][Cd(NO3)3(L2)]} and {[Cd(NO3)2]2(L5)3}.
Co-reporter:Xiang Lin Dr.;Junhua Jia;Xuebo Zhao Dr.;K. Mark Thomas Dr.;Alexer J. Blake Dr.;Gavin S. Walker Dr. Dr.;Peter Hubberstey Dr.;Martin Schröder Dr.
Angewandte Chemie International Edition 2006 Volume 45(Issue 44) pp:
Publication Date(Web):23 AUG 2006
DOI:10.1002/anie.200601991
First-class accommodation: A series of coordination frameworks with different pore sizes (see structure of one; Cu blue, C gray, H white, O red) are prepared from CuII ions and carboxylate ligands of various lengths. Comparison of their sorption properties reveals that smaller pores allow higher densities of adsorbed H2, whereas larger pores allow higher maximum H2 storage capacities.
Co-reporter:Sarah A. Barnett, Alexander J. Blake, Neil R. Champness and Claire Wilson
Dalton Transactions 2005 (Issue 24) pp:3852-3861
Publication Date(Web):09 Sep 2005
DOI:10.1039/B509294A
A family of two-dimensional coordination polymers formed from the reaction of Cd(NO3)2 with pyrazine or pyrimidine is reported, including rare examples of polymorphic coordination polymers which crystallise as multiple crystals. Six coordination polymers have been structurally characterised, four for pyrazine and two for pyrimidine-based systems, all of which form two-dimensional arrays utilising pyrazine/pyrimidine bridging, in some instances in combination with nitrate bridging. The compounds form either 44 grids (1, 3, 4, 5), or in one instance, a 63 herringbone sheet structure (2). In the case of 3, two polymorphs have been identified, 3a and 3b, in which the three-dimensional arrangements of the coordination polymers differ only in the relative ordering of adjacent two-dimensional sheets. It was found that these two polymorphs crystallise in a simultaneous fashion such that each crystal studied was found to contain regions of both polymorphs and was believed to be a multiple crystal. Assessment of the phase purity of the product from the reaction of Cd(NO3)2 with either pyrazine or pyrimidine indicates that compounds 1 and 5 are not formed when the products are formed by rapid precipitation but only when using slow-diffusion methods. It is also apparent that in almost all instances more than one product is formed from a given reaction thereby illustrating the complexity of coordination polymer formation even when using simple building-blocks. For the crystal engineer this complexity is perhaps best illustrated by the simultaneous formation of 3a and 3b where no chemical interactions differentiate the two polymorphs, presenting a seemingly insurmountable complexity in the engineering of these systems.
Co-reporter:Neil S. Oxtoby, Neil R. Champness and Claire Wilson
CrystEngComm 2005 vol. 7(Issue 46) pp:284-288
Publication Date(Web):11 Apr 2005
DOI:10.1039/B502209F
Two coordination polymers, [(CoCl2)3(dpztz)2]∞ and [Cd(NO3)2(dpztz)]∞, have been prepared using the multi-modal ligand 3,6-di-pyrazin-2-yl-(1,2,4,5)-tetrazine (dpztz). [(CoCl2)3(dpztz)2]∞ adopts a three-dimensional CdSO4-like framework structure in which two distinct Co(II) coordination environments are observed. Whilst both Co(II) centres are coordinated by two chloride ligands in a trans-arrangement, one Co(II) is coordinated by two chelating sites from two dpztz ligands and the other Co(II) cation is coordinated by four pyrazine donors from four separate dpztz ligands. The observation of two distinct metal environments in a coordination framework is unusual for systems employing multi-modal ligands. In contrast Cd(NO3)2(dpztz)]∞ adopts a one-dimensional chain structure in which each Cd(II) cation is coordinated exclusively by chelating dpztz sites, in addition to two bidentate nitrate anions.
Co-reporter:Sarah A. Barnett;Claire Wilson
European Journal of Inorganic Chemistry 2005 Volume 2005(Issue 8) pp:
Publication Date(Web):21 APR 2005
DOI:10.1002/ejic.200401035
An isostructural family of one-dimensional coordination polymers, [M(NO3)2(pym)(H2O)2]∞ [M = Mn (1), Co (2), Ni (3), Zn (4); pym = pyrimidine], has been prepared and their phase purity assessed. It is shown that in contrast to otherM(NO3)2–pyrimidine coordination polymers, 1–4 show a surprising preference for the structure reported herein rather the wide variety of other possible product architectures. It is also shown that a related complex [Ni(NO3)2(pym)(MeCN)2]∞ (5), in which water ligands observed in 1–4 are replaced by MeCN molecules, can also be prepared. However, 5 is highly hygroscopic and readily converts to 3 in the presence of atmospheric water. The implication of the uniformity of structure is discussed in relation to the serendipitous coordination of water molecules to the metal centres. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Co-reporter:Robert J. Hill, De-Liang Long, Peter Hubberstey, Martin Schröder, Neil R. Champness
Journal of Solid State Chemistry 2005 Volume 178(Issue 8) pp:2414-2419
Publication Date(Web):August 2005
DOI:10.1016/j.jssc.2005.05.008
Significant successes have been made over recent years in preparing co-ordination framework polymers that show macroscopic material properties, but in the vast majority of cases this has been achieved with d-block metal-based systems. Lanthanide co-ordination frameworks also offer attractive properties in terms of their potential applications as luminescent, non-linear optical and porous materials. However, lanthanide-based systems have been far less studied to date than their d-block counterparts. One possible reason for this is that the co-ordination spheres of lanthanide cations are more difficult to control and, in the absence of design strategies for lanthanide co-ordination frameworks, it is significantly more difficult to target materials with specific properties. However, this article highlights some of the exciting possibilities that have emerged from the earliest investigations in this field with new topological families of compounds being discovered from relatively simple framework components, including unusual eight, seven and five-connected framework systems. Our own research, as well as others, is leading to a much greater appreciation of the factors that control framework formation and the resultant observed topologies of these polymers. As this understanding develops targeting particular framework types will become more straightforward and the development of designed polyfunctional materials more accessible. Thus, it can be seen that lanthanide co-ordination frameworks have the potential to open up previously unexplored directions for materials chemistry. This article focuses on the underlying concepts for the construction of these enticing and potentially highly important materials.Lanthanide co-ordination frameworks provide unique and enticing structural features and have the potential to open up previously unexplored directions for materials chemistry.
Co-reporter:Neil S. Oxtoby Dr.;Alexer J. Blake Dr. Dr.;Claire Wilson Dr.
Chemistry - A European Journal 2005 Volume 11(Issue 16) pp:
Publication Date(Web):25 MAY 2005
DOI:10.1002/chem.200500091
A strategy for encouraging the formation of extended water arrays is presented, in which molecules that contain a 1,4-dihydroquinoxaline-2,3-dione core are used as supramolecular hosts for the accommodation of guest water molecules and arrays. These molecules were selected as they contain a hydrophilic oxalamide-based “terminus” that allows water molecules to hydrogen-bond to the host organic molecules as well as to each other. The host molecules also contain a hydrophobic “end” based upon an aromatic ring, which serves to encourage the formation of discrete water clusters in preference to three-dimensional networks, as the water molecules cannot form strong hydrogen bonds with this part of the molecule. A systematic study of several hydrated structures of four organic molecules based on 1,4-dihydroquinoxaline-2,3-dione (qd) is discussed. The organic molecules, qd, 6-methyl-1,4-dihydroquinoxaline-2,3-dione (mqd), 6,7-dimethyl-1,4-dihydroquinoxaline-2,3-dione (dmqd) and 1,4-dihydrobenzo[g]quinoxaline-2,3-dione (Phqd), act as supramolecular crystal hosts for the clusters of water, with zero-, one- and two-dimensional arrays of water being observed. The hydrogen bonding in the structures, both within the water clusters and between the clusters and organic molecules, is examined. In particular, the structure of dmqd⋅6 H2O contains a two-dimensional water sheet composed of pentagonal and octagonal units. Phqd⋅3 H2O forms a hydrophilic extended structure encouraging the formation of one-dimensional chains consisting entirely of water. Both qd⋅2 H2O and dmqd⋅2 H2O can be considered to form one-dimensional chains, but only by utilising bridging carbonyl groups of the oxalamide moieties to form the extended array; if only the water is considered, zero-dimensional water tetramers are observed. The remaining hydrated structures, [Na+dmqd−]dmqd⋅H2O, dmqd⋅1/3H2O and mqd⋅1/2H2O, all contain discrete water molecules but do not form extended water structures.
Co-reporter:De-Liang Long Dr.;Robert J. Hill;Alexer J. Blake Dr. Dr.;Peter Hubberstey Dr.;Claire Wilson Dr.;Martin Schröder Dr.
Chemistry - A European Journal 2005 Volume 11(Issue 5) pp:
Publication Date(Web):24 JAN 2005
DOI:10.1002/chem.200400594
Reaction of ScX3 (X=NO3−, CF3SO3−, ClO4−) with 4,4′-bipyridine-N,N′-dioxide (L) affords topologically distinct six-connected three-dimensional coordination frameworks, {[Sc(L)3](NO3)3}∞ (1), {[Sc(L)3](CF3SO3)3(CH3OH)2.7(H2O)3}∞ (2), {[Sc(L)3](ClO4)3}∞ (3) and {[Sc(L)4(H2O)2](ClO4)3}∞ (4). Compounds 1, 2 and 3 are networks based on octahedrally co-ordinated ScO6 centres bound through six oxygen atoms from six separate N-oxide ligands L. Compounds 1 and 3 are doubly interpenetrated and have α-polonium-type structures of 41263 topology based upon three intersecting (4,4) nets. The structure of 2 is unusual and shows parallel, co-planar layers of (4,4) nets connected in a criss-crossed fashion to afford a new 48668 topology. In 4 only four ligands L bind to each ScIII centre with two additional water molecules bridging metal nodes. Significantly, the bridges formed by L do not sit in a plane and if connections through L are considered alone the resultant structure is a diamondoid array typically based upon a tetrahedral connecting node at Sc. Five interpenetrating diamondoid networks are observed that are cross-bridged by water molecules to form a single three-dimensional array of 4867 topology. Compound 4 can also be viewed as incorporating two intersecting (4,4) grids based upon two ligands L and two bridging waters. Thus, variation of anion, solvent and conditions critically affects the structures of products formed, and the series of polymers reported herein illustrates how tectons based upon (4,4) grids can be combined and distorted to form non-NaCl topologies and even cross-bridged, multiply interpenetrated diamondoid materials. Both compounds 2 and 4 represent unusual examples of self-penetrated coordination frameworks.
Co-reporter:Robert J. Hill, De-Liang Long, Mark S. Turvey, Alexander J. Blake, Neil R. Champness, Peter Hubberstey, Claire Wilson and Martin Schröder
Chemical Communications 2004 (Issue 16) pp:1792-1793
Publication Date(Web):21 Jul 2004
DOI:10.1039/B407554D
Three bilayer structures with unprecedented 6-connected topology and a single example of a bilayer structure with 5-connected topology have been generated by co-ordination of 4,4′-bipyridine-N,N′-dioxide at La(III), Yb(III) or Er(III) nodes.
Co-reporter:Oleg V. Dolomanov, David B. Cordes, Neil R. Champness, Alexander J. Blake, Lyall R. Hanton, Geoffrey B. Jameson, Martin Schröder and Claire Wilson
Chemical Communications 2004 (Issue 6) pp:642-643
Publication Date(Web):16 Feb 2004
DOI:10.1039/B315243J
Reactions of tetrahedral Cu(I) and Ag(I) cations with 2,3,4,5-tetra(4-pyridyl)thiophene allows targeted construction of coordination frameworks with zeolite-like, 42.84, topologies.
Co-reporter:De-Liang Long Dr.;Robert J. Hill;Alexer J. Blake Dr. Dr.;Peter Hubberstey Dr.;Davide M. Proserpio Dr.;Claire Wilson Dr.;Martin Schröder Dr.
Angewandte Chemie International Edition 2004 Volume 43(Issue 14) pp:
Publication Date(Web):24 MAR 2004
DOI:10.1002/anie.200352625
Non-CsCl topologies for eight-connected solid-state materials have been observed for the first time in three networks based on lanthanide cations and 4,4′-bipyridine-N,N′-dioxide ligands. The structure of the {[Yb(L)4](CF3SO3)3}∞ network is depicted.
Co-reporter:De-Liang Long Dr.;Robert J. Hill;Alexer J. Blake Dr. Dr.;Peter Hubberstey Dr.;Davide M. Proserpio Dr.;Claire Wilson Dr.;Martin Schröder Dr.
Angewandte Chemie 2004 Volume 116(Issue 14) pp:
Publication Date(Web):24 MAR 2004
DOI:10.1002/ange.200352625
Nicht-CsCl-Topologien wurden für achtfach verknüpfte Materialien in fester Phase erstmals in drei Netzwerken beobachtet, die auf Lanthanoid-Kationen und 4,4′-Bipyridin-N,N′-dioxid-Liganden basieren. Das Bild zeigt die Struktur des {[Yb(L)4](CF3SO3)3}∞-Netzwerks.
Co-reporter:Oleg V. Dolomanov, Alexander J. Blake, Neil R. Champness, Martin Schröder and Claire Wilson
Chemical Communications 2003 (Issue 6) pp:682-683
Publication Date(Web):18 Feb 2003
DOI:10.1039/B300605K
Hexanuclear cage complexes [M6L6X](X)5 [M = Cu(I), Ag(I); L = 6,6′-bis(4-ethynylpyridine)2,2′-bipyridine; X = BF4−, SbF6−] have been prepared using a self-assembly approach; these architectures encapsulate anions in the solid-state and are fluxional in solution.
Co-reporter:Sarah A. Barnett, Alexander J. Blake and Neil R. Champness
CrystEngComm 2003 vol. 5(Issue 24) pp:134-136
Publication Date(Web):06 May 2003
DOI:10.1039/B303338D
The crystal structures of two polymorphic hydrogen bonded networks formed by cyanuric acid (CA) and bis(4-pyridyl)ethene (bpe) are described. In both instances two-dimensional sheets are constructed from CA chains that are cross-linked by bpe moieties. Although all the sheets in both compounds adopt essentially equivalent hydrogen bonding connectivity, two different sheet arrangements are observed due to subtle variations in the N–H⋯O hydrogen bonds between CA molecules. In one polymorph only one type of sheet is observed while in the other both sheet arrangements occur.
Co-reporter:Sarah A. Barnett, Alexander J. Blake, Neil R. Champness and Claire Wilson
Dalton Transactions 2003 (Issue 12) pp:2387-2394
Publication Date(Web):06 May 2003
DOI:10.1039/B302807K
The reactions of 4,7-phenanthroline (4,7-phen) with a variety of metal salts have been investigated and the products structurally characterised by single crystal X-ray diffraction. Reaction of CoX2
(X = Cl, Br) or M(NO3)2
(M = Cd, Zn, Ni) salts with 4,7-phen all afford one-dimensional coordination polymers, [CoX2(4,7-phen)]∞
(1, 2) or [M(NO3)2(4,7-phen)(H2O)]∞
(M = Cd 3, Zn 4, Ni 5), in which the metal centres are linked via 4,7-phen ligands which act in a bridging bidentate manner. The remaining metal coordination sites are occupied by either halide (1, 2) or NO3− and H2O ligands (3–5). In{[Ni(NO3)2(4,7-phen)(H2O)]·(4,7-phen)}∞, 5 an additional, uncoordinated, molecule of 4,7-phen is included in the structure, hydrogen bonded to a coordinated H2O molecule. In contrast, reaction of CuX2
(X = Cl, Br) or Cu(NO3)2 with 4,7-phen leads to the formation of discrete complexes, [CuX2(4,7-phen)2]
(X = Cl 6, Br 7, NO38) in which the N-donor ligand coordinates in a monodentate fashion and π–π interactions between coordinated 4,7-phen molecules generate an extended structure in the solid state. Investigation of the phase purity of 4 and 5 revealed that in the case of 4 the coordination polymer formed only in the presence of a previously reported hydrogen bonded structure, while 5 was shown to be contaminated with an unidentified phase. The rôle and diversity of the interactions adopted by 4,7-phen in forming coordination polymers and related species are discussed.
Co-reporter:Neil S. Oxtoby, Alexander J. Blake, Neil R. Champness and Claire Wilson
Dalton Transactions 2003 (Issue 20) pp:3838-3839
Publication Date(Web):12 Sep 2003
DOI:10.1039/B310754J
Control over ligand donor arrangement leads to structural discrimination between one- and two-dimensions in two coordination frameworks, {[AgNO3]2L}∞, formed between AgNO3 and hexadentate multi-modal ligands.
Co-reporter:Neil S. Oxtoby, Alexander J. Blake, Neil R. Champness and Claire Wilson
CrystEngComm 2003 vol. 5(Issue 17) pp:82-86
Publication Date(Web):25 Mar 2003
DOI:10.1039/B302187D
The crystal structures of 3,6-dipyridin-3-yl-(1,2,4,5)-tetrazine, 3,6-dipyridin-4-yl-(1,2,4,5)-tetrazine and 3,6-dipyrazin-2-yl-(1,2,4,5)-tetrazine are reported. The packing arrangements of these three compounds containing 1,2,4,5-tetrazine rings are examined. The 1,2,4,5-tetrazine rings are electron deficient with respect to phenyl rings and the effect this has upon the observed packing motifs is discussed.
Co-reporter:Sarah A. Barnett, Alexander J. Blake, Neil R. Champness and Claire Wilson
Chemical Communications 2002 (Issue 15) pp:1640-1641
Publication Date(Web):03 Jul 2002
DOI:10.1039/B203661D
CuSCN reacts with the angular ligand 2,4-bis(4-pyridyl)-1,3,5-triazine (dpt) to afford rare examples of coordination polymer structural isomers including a non-centrosymmetric three-dimensional framework with Cd(SO4) topology constructed from tetrahedral metal cations.
Co-reporter:Andrei N. Khlobystov, Neil R. Champness, Clive J. Roberts, Saul J.B. Tendler, Claire Thompson and Martin Schröder
CrystEngComm 2002 vol. 4(Issue 71) pp:426-431
Publication Date(Web):19 Jul 2002
DOI:10.1039/B202217F
Interconversion of chain co-ordination polymers {[Ag(4,4′-bipy)](X)}∞
(X = NO3− or BF4−) in aqueous media has been studied by IR and 1H NMR spectroscopy, transmission electron (TEM) and atomic force (AFM) microscopies and by X-ray powder diffraction (PXRD). The exchange leads to the formation of a pure crystalline phase of a new co-ordination polymer, and detailed TEM and AFM studies indicate a solvent-mediated rather than a solid-state mechanism for the exchange process.
Co-reporter:Sarah. A. Barnett
Heteroatom Chemistry 2002 Volume 13(Issue 6) pp:574-577
Publication Date(Web):28 AUG 2002
DOI:10.1002/hc.10092
The use of the building-block methodology in designing coordination framework materials are discussed, with particular reference to the structural reliability of a given building block. The term structural reliability is defined for a given metal containing moiety as the degree to which that building block reproducibly adopts a given, predicted, coordination arrangement when reacted with a series of chemically related bridging ligands. This terminology is discussed with respect to a range of coordination frameworks constructed using Cd(NO3)2 as a building-block, which is demonstrated to be structurally unreliable. © 2002 Wiley Periodicals, Inc. Heteroatom Chem 13:574–577, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.10092
Co-reporter:Alexander J. Blake;Neil S. Oxtoby;Claire Wilson
PNAS 2002 Volume 99 (Issue 8 ) pp:4905-4910
Publication Date(Web):2002-04-16
DOI:10.1073/pnas.082647399
A range of Ag(I) one- and two-dimensional coordination frameworks has been prepared and structurally characterized by using
the multimodal ligand 3,6-di-pyrazin-2-yl-(1,2,4,5)-tetrazine, which offers both monodentate and chelating binding sites.
It is demonstrated that multimodal ligands can be used to prepare coordination frameworks with novel and unusual topologies
and to influence the precise geometrical arrangement of both ligands and metal centers within such supramolecular arrays.
Co-reporter:De-Liang Long Dr.;Alexer J. Blake Dr. Dr.;Claire Wilson Dr.;Martin Schröder Dr.
Chemistry - A European Journal 2002 Volume 8(Issue 9) pp:
Publication Date(Web):24 APR 2002
DOI:10.1002/1521-3765(20020503)8:9<2026::AID-CHEM2026>3.0.CO;2-8
Five different co-ordination polymers of terbium(III) and the bidentate ligand 4,4′-bipyridine-N,N′-dioxide (L), [Tb(L)(CH3OH)(NO3)3]∞ (1), {[Tb(L)1.5(NO3)3]⋅CH2Cl2}∞ (2), {[Tb(L)1.5(NO3)3]⋅CH3OH⋅0.8H2O}∞ (3), {[Tb(L)1.5(NO3)3]⋅0.4C2Cl4⋅0.8CH3OH}∞ (4), and [Tb(L)2(NO3)3]∞ (5) have been synthesised by the use of different “diffusion solvent mixtures”, and structurally characterised by X-ray crystallography. Compound 1, with a Tb:L stoichiometry of 1:1, adopts a zig-zag chain structure, which forms three-fold interpenetrating diamondoid frameworks through interchain hydrogen bonding between co-ordinated methanol and a nitrate group on an adjacent chain. Polymers 2, 3, and 4 all have a Tb:L stoichiometry of 1:1.5, but adopt different topologies. For 2, a ladder arrangement is found and large channels which accommodate solvent CH2Cl2 molecules are formed by superposition of the ladders. For 3 and 4 4.82 net structures are observed. The superposition of the 4.82 nets in 3 and 4, by disposing adjacent layers such that every octagon is positioned below a tetragon from the neighbouring layer, allows the formation of two kinds of channel, with that inside the tetragons accommodating methanol molecules. The other kind of channel, between tetragons, accommodates water molecules in the case of 3 and tetrachloroethylene molecules in the case of 4. Compound 5, with a Tb:L stoichiometry of 1:2, has a linear polymeric structure with one bridging and one terminal ligand, and forms (6,3) plane nets by means of intermolecular electrostatic interactions between N-oxide moieties. X-ray powder diffraction studies show that upon desolvation, compound 2 maintains its original ladder framework.
Co-reporter:Sarah A Barnett, Alexander J Blake, Neil R Champness, Claire Wilson
Journal of Supramolecular Chemistry 2002 Volume 2(1–3) pp:17-20
Publication Date(Web):January–June 2002
DOI:10.1016/S1472-7862(02)00066-7
4,7-Phenanthroline (L) acts as a hydrogen-bond acceptor in the compounds {[M(NO3)2(H2O)4].L2} (M=Mn, Co, Ni, Zn) forming square-grid hydrogen-bonded structures which are linked into an α-Po three-dimensional structure via supplementary hydrogen bonding and π–π interactions.4,7-Phenanthroline (L) acts as a hydrogen-bond acceptor in the compounds {[M(NO3)2(H2O)4].L2} (M=Mn, Co, Ni, Zn) forming square-grid hydrogen-bonded structures which are linked into an α-Po three-dimensional structure via supplementary hydrogen bonding and π–π interactions.
Co-reporter:Andrei N. Khlobystov, Alexander J. Blake, Neil R. Champness, Dmitrii A. Lemenovskii, Alexandre G. Majouga, Nikolai V. Zyk, Martin Schröder
Coordination Chemistry Reviews 2001 Volume 222(Issue 1) pp:155-192
Publication Date(Web):November 2001
DOI:10.1016/S0010-8545(01)00370-8
This review discusses the design and structure of coordination polymers derived from Ag(I) with N-donor ligands and their role in the investigation of weak non-covalent interactions in the solid state. These forces include arene–arene, metal–anion, metal–arene and metal–metal interactions. The main purpose of this review is to classify and discuss the supramolecular forces which define the overall observed structure (topology, geometry and packing arrangement) of coordination polymers by comparison of a series of structurally related compounds when one parameter of the multi-component system (choice of anion, ligand or solvent) is varied. Design criteria for one-dimensional polymers are given and discussed with respect to the fundamental importance of these compounds for understanding and further development of supramolecular synthetic strategies.
Co-reporter:Alexander J. Blake, Matthew T. Brett, Neil R. Champness, Andrei N. Khlobystov, De-Liang Long, Claire Wilson and Martin Schröder
Chemical Communications 2001 (Issue 21) pp:2258-2259
Publication Date(Web):11 Oct 2001
DOI:10.1039/B106348K
4,4′-Bipyridine N,N′-dioxide (L) acts as a hydrogen-bond acceptor in the compounds {[M(NO3)2(H2O)4]·L 2} (M = Co, Ni) to form doubly-interpenetrated framework materials with sixfold topological connectivity.
Co-reporter:Alexander J. Blake, Neil R. Brooks, Neil R. Champness, Marcello Crew, Anne Deveson, Dieter Fenske, Duncan H. Gregory, Lyall R. Hanton, Peter Hubberstey and Martin Schröder
Chemical Communications 2001 (Issue 16) pp:1432-1433
Publication Date(Web):19 Jul 2001
DOI:10.1039/B103612M
Three coordination polymers formed between CuI and bpds [bpds
= bis(4-pyridyl)disulfide] have been prepared and fully characterised
illustrating rare examples of solvent dependent topological isomerism in
[(CuI)2(bpds)]∞; tetrahedral
Cu4I4 cubane junctions are linked to give either
necklace or tubular polymers.
Co-reporter:Neil R. Brooks, Alexander J. Blake, Neil R. Champness, John W. Cunningham, Peter Hubberstey, Simon J. Teat, Claire Wilson and Martin Schröder
Dalton Transactions 2001 (Issue 17) pp:2530-2538
Publication Date(Web):10 Aug 2001
DOI:10.1039/B100635P
The reaction of Ag(I) salts with 1,4-dithiane has produced several interesting co-ordination polymers, the structures of which vary significantly with anion. Compounds with metal ∶ ligand ratios of 2 ∶ 3, 1 ∶ 1 and 2 ∶ 1 have been produced and are discussed in the context of the influence of the anion on structural order. The recurrent topological feature of the three 2 ∶ 3 adducts, [{[Ag2(μ2-1,4-dithiane)3][BF4]2}∞, {[Ag2(μ2-1,4-dithiane)3][CF3SO3]2}∞ and {[Ag2(μ2-1,4-dithiane)3][NO3]2}∞], is a {[Ag2(μ2-1,4-dithiane)3]2+}∞ honeycomb sheet of (6,3) topology. The principal differences between these sheets lie in the size and symmetry of the constituent hexagonal units, the packing of the sheets being governed by the anion. For the polymers with [BF4−] and [CF3SO3−] anions, parallel sheets align such that the anions, which complete the four-fold co-ordination of the Ag(I) centres, are located in the hexagonal cavities of adjacent sheets; for the polymers with [NO3−] anions, however, the sheets are perpendicularly interpenetrated. The structures of the three 1 ∶ 1 adducts, {[Ag(μ2-1,4-dithiane)][BF4]}∞, {[Ag(μ2-1,4-dithiane)][SCN]}∞ and {[Ag(μ2-1,4-dithiane)][NO2]}∞, are all based on the same building block, a {[Ag(μ2-1,4-dithiane)]+}∞ chain of alternating metal and organic fragments. They differ, however, in the construction of their extended networks, which are anion dependent. All three anions bridge four-co-ordinate Ag(I) centres to form {[Ag(μ-X)]−}∞ chains which criss-cross the {[Ag(μ2-1,4-dithiane)]+}∞ chains. In the cases where [BF4−] and [SCN−] anions are used, the interlinked chains generate 2-D sheets with (4,4) topology which space fill either by perpendicular two-fold interpenetration to give a 3-D CdSO4 net (for the [BF4−] complex) or by parallel stacking (for the [SCN−] complex). In contrast, when [NO2−] acts as the anion, the interlinked chains give a 3-D diamondoid network. The 2 ∶ 1 polymer, {[Ag2(μ4-1,4-dithiane)][SO4]·H2O}∞, has an unprecedented 3-D architecture in which inorganic pillars brace metal–organic sheets. The metal–organic sheets comprise Ag(I) centres linked by μ2-S, μ2-S′ bridging 1,4-dithiane ligands and the inorganic pillars comprise Ag(I) centres connected by μ1-O (μ1-O is used in this instance to describe an oxygen atom bound to only one silver atom), μ1-O′, μ2-O″-bridging sulfate anions and μ2-O-bridging H2O molecules.
Co-reporter:Sarah A. Barnett, Alexander J. Blake, Neil R. Champness, James E. B. Nicolson and Claire Wilson
Dalton Transactions 2001 (Issue 5) pp:567-573
Publication Date(Web):09 Feb 2001
DOI:10.1039/B008715G
Coordination polymers formed between Cd(NO3)2 or Zn(NO3)2 and 2,4-bis(4-pyridyl)-1,3,5-triazine (dpt) have been synthesized and their single crystal structures determined. Reaction of a 1∶1 ratio of Cd(NO3)2 with dpt in MeCN–CH2Cl2 affords the complex [Cd2(NO3)4(dpt)2(MeCN)]∞ 1 which exists as a doubly interpenetrated 4.82 two-dimensional sheet in the solid state. Each sheet is constructed from nitrate-bridged [Cd(dpt)]4 metallacycles. In sharp contrast the analogous reaction performed using a 2∶1 L∶M ratio affords the discrete molecular complex [Cd(NO3)2(dpt)2(MeCN)] 2 in which both dpt ligands act as terminal donors rather than bridging metal centres. Reaction of Cd(NO3)2 with dpt in EtOH–CH2Cl2 affords a one-dimensional coordination polymer [Cd(NO3)2(dpt)(EtOH)]∞ 3. Zn(NO3)2 reacts with dpt in either a 1∶1 or 2∶1 L∶M ratio to afford the one-dimensional polymer [Zn(NO3)2(dpt)]∞ 4 which can be isolated as two polymorphs 4a and 4b which differ in their nitrate binding modes. The product formed is independent of the L∶M ratio used in the reaction. Only 4a is formed when MeCN–CH2Cl2 is used as reaction solvent whereas both 4a and 4b are formed from either EtOH–CH2Cl2 or iPrOH–CH2Cl2.
Co-reporter:Neil R. Brooks, Alexander J. Blake, Neil R. Champness, Paul A. Cooke, Peter Hubberstey, Davide M. Proserpio, Claire Wilson and Martin Schröder
Dalton Transactions 2001 (Issue 4) pp:456-465
Publication Date(Web):31 Jan 2001
DOI:10.1039/B008202N
A series of complexes of copper(I) halides with either [12]aneS4 (1,4,7,10-tetrathiacyclododecane) or [16]aneS4 (1,5,9,13-tetrathiacyclohexadecane) have been synthesized, characterised and their crystal structures determined. Discrete molecular entities of formula [CuX([12]aneS4)] (X = Cl, Br or I) were isolated from solutions containing a 1∶1 metal∶ligand stoichiometry. In [CuX([12]aneS4)] (X = Br or I) the copper(I) centres adopt a rare square pyramidal geometry. Located on fourfold axes of symmetry, the copper(I) centres are co-ordinated by one halide ion [Cu–Br 2.4209(11) or Cu–I 2.573(5) Å] and four sulfur atoms [2.5386(12) (X = Br) and 2.521(5) Å (X = I)]. In contrast, the copper(I) centres in [CuCl([12]aneS4)] adopt the more common tetrahedral co-ordination geometry, which is provided by one chloride ion [Cu–Cl 2.2666(13) Å] and three sulfur donors [Cu–S 2.3331(13), 2.3326(13), 2.4720(11) Å]. Polymeric materials, [Cu4Br4([12]aneS4)2]∞, [Cu4I4([12]aneS4)]∞ and [Cu2I2([16]aneS4)]∞, were obtained from reactions in which metal∶ ligand stoichiometries of 2∶1 and 4∶1 were used. [Cu4Br4([12]aneS4)2]∞ contains a previously uncharacterised copper(I) halide motif of formula Cu4X4 which is derived from the common Cu4X4 cubane tetramer and the Cu4X4 step-cubane tetramer. These Cu4X4 clusters are linked by [12]aneS4 molecules to generate a two-dimensional framework [Cu–Br 2.410(2)–2.539(2); Cu–S 2.318(3)–2.385(3) Å]. In [Cu4I4([12]aneS4)]∞, Cu4I4 cubane tetramers are linked by tetradentate [12]aneS4 molecules to give a two-dimensional sheet structure [Cu–I 2.602(1)–3.021(1); Cu–S 2.285(1)]. In [Cu2I2([16]aneS4)]∞ an infinite three-dimensional co-ordination polymer comprising Cu2I2 rhomboid dimers linked by tetradentate [16]aneS4 molecules is formed [Cu–I 2.5972(9)–2.6702(9); Cu–S 2.292(2)–2.357(2) Å]. The Cu2I2 moiety acts as a pseudo-square planar linker while the bridging [16]aneS4 units afford tetrahedral building blocks to give overall a PtS type structure for the polymer.
Co-reporter:De-Liang Long Dr.;Alexer J. Blake Dr. Dr.;Claire Wilson Dr.;Martin Schröder Dr.
Angewandte Chemie 2001 Volume 113(Issue 13) pp:
Publication Date(Web):2 JUL 2001
DOI:10.1002/1521-3757(20010702)113:13<2509::AID-ANGE2509>3.0.CO;2-N
Achtfach koordinierte Metallionen als Knotenpunkte sind in den hier beschriebenen Koordinationsnetzwerken – den ersten mit siebenfacher oder achtfacher Konnektivität – über 4,4-Bipyridin-N,N′-dioxid als Brückenligand (L) verbunden. Während [La(L)4](CF3SO3)3 eine hyperkubisch-innenzentrierte, CsCl-ähnliche Gitterstruktur mit achtfach verknüpften Zentren hat (siehe Bild), sind die Metallionen in [La(L)4](BPh4)(ClO4)2 zwar ebenfalls achtfach koordiniert, jedoch siebenfach verknüpft und weisen eine bisher unbekannte 41762-Topologie auf.
Co-reporter:Alexander J. Blake, Neil R. Champness, Paul A. Cooke and James E. B. Nicolson
Chemical Communications 2000 (Issue 8) pp:665-666
Publication Date(Web):03 Apr 2000
DOI:10.1039/A909868B
Depending on the crystallisation solvent used, reaction of
2,2′-bipyrazine with AgBF4 results in the formation of
either a chiral three-dimensional adamantoid coordination network or a
two-dimensional sheet incorporating five coordinate Ag(I)
ions.
Co-reporter:De-Liang Long, Alexander J. Blake, Neil R. Champness and Martin Schröder
Chemical Communications 2000 (Issue 22) pp:2273-2274
Publication Date(Web):07 Nov 2000
DOI:10.1039/B006679F
Various binding modes of 4,4′-bipyridine
N,N′-dioxide (L) for crystal engineering are
demonstrated in the complexes
[Zn(MeOH)2L3](SiF6)·3MeOH and
[ZnL6](NO3)2, which include examples of
M–L coordination bonds, hydrogen-bonding and π–π stacking
interactions.
Co-reporter:Alexander J. Blake, Neil R. Champness, Paul A. Cooke, James E. B. Nicolson and Claire Wilson
Dalton Transactions 2000 (Issue 21) pp:3811-3819
Publication Date(Web):10 Oct 2000
DOI:10.1039/B003202F
The influence of solvent and anion on the formation of co-ordination polymers of silver(I) and the multi-modal ligands 2,2′-bipyrazine (bpyz) and pyrazino[2,3-f]quinoxaline (pyq) has been studied. Reaction of AgX (X = BF4− or PF6−) with bpyz or pyq in MeNO2 affords three-dimensional co-ordination networks, {[Ag(bpyz)]X}∞ or {[Ag(pyq)]X}∞. Whereas {[Ag(bpyz)]X}∞ form diamond-like networks, which adopt a chiral structure due to the different bridging modes of the bpyz ligand, {[Ag(pyq)]X}∞ form unusual achiral three-dimensional frameworks which are constructed from bridged [Ag(pyq)]∞ tubes. In the case of {[Ag(bpyz)]X}∞ an increase in anion volume from BF4− to PF6− leads to a corresponding increase in helix volume and concomitant contraction of the helical pitch of the diamondoid framework. The use of co-ordinating solvents of crystallisation in the reactions of AgBF4 with bpyz results in the formation of an undulating two-dimensional sheet, {[Ag(bpyz)(MeCN)]BF4}∞, when MeCN replaces MeNO2, or a one-dimensional polymer {[Ag2(bpyz)2(PhCN)][BF4]2}∞, when PhCN is used. Reaction of AgBF4 with pyq in either MeCN or PhCN affords the discrete molecular complex [Ag(pyq)2]BF4 in which only the chelating donors of the pyq ligand are co-ordinated to the silver(I) ion. [Ag(pyq)2]BF4 exhibits dimorphism with the two structures observed differing in the nature of their π–π interactions.
Co-reporter:Alexer J. Blake Dr.;Neil R. Champness Dr.;Andrei N. Khlobystov Dr.;Simon Parsons Dr.;Martin Schröder Dr.
Angewandte Chemie 2000 Volume 112(Issue 13) pp:
Publication Date(Web):4 JUL 2000
DOI:10.1002/1521-3757(20000703)112:13<2407::AID-ANGE2407>3.0.CO;2-7
Co-reporter:Kunal S. Mali, Nicholas Pearce, Steven De Feyter and Neil R. Champness
Chemical Society Reviews 2017 - vol. 46(Issue 9) pp:NaN2542-2542
Publication Date(Web):2017/04/12
DOI:10.1039/C7CS00113D
The application of supramolecular chemistry on solid surfaces represents an exciting field of research that continues to develop in new and unexpected directions. This review highlights recent advances in the field which range from the fundamental aspects of the thermodynamics of self-assembly through to the development of new materials with potential application as new materials. The unique aspects of working on solid surfaces are highlighted and advances in the assembly of many component systems and highly complex fractal-like and quasicrystalline systems discussed. The unique features of working in the surface-based environment and the utilisation of scanning probe microscopies as a primary characterisation tool are highlighted.
Co-reporter:Matthew Blunt, Xiang Lin, Maria del Carmen Gimenez-Lopez, Martin Schröder, Neil R. Champness and Peter H. Beton
Chemical Communications 2008(Issue 20) pp:NaN2306-2306
Publication Date(Web):2008/04/08
DOI:10.1039/B801267A
The use of a coronene guest template directs the formation of a 2D Kagomé network in preference to alternative close packed and parallel hydrogen-bonded structures of tetracarboxylic acid tectons self-assembled from solution on a graphite surface.
Co-reporter:Andrea Laybourn, Juliano Katrib, Rebecca S. Ferrari-John, Christopher G. Morris, Sihai Yang, Ofonime Udoudo, Timothy L. Easun, Chris Dodds, Neil R. Champness, Samuel W. Kingman and Martin Schröder
Journal of Materials Chemistry A 2017 - vol. 5(Issue 16) pp:NaN7338-7338
Publication Date(Web):2017/04/05
DOI:10.1039/C7TA01493G
Synthesis of metal–organic framework (MOF) materials via microwave heating often involves shorter reaction times and offers enhanced control of particle size compared to conventional heating. However, there is little understanding of the interactions between electromagnetic waves and MOFs, their reactants, and intermediates, all of which are required for successful scale-up to enable production of commercially viable quantities of material. By examining the effect of average absorbed power with a constant total absorbed energy to prepare MIL-53(Al) we have defined a selective heating mechanism that affords control over MOF particle size range and morphology by altering the microwave power. This is the first time a selective mechanism has been established for the preparation of MOFs via microwave heating. This approach has been applied to the very rapid preparation of MIL-53(Al)ta (62 mg in 4.3 seconds) which represents the fastest reported synthesis of a MOF on this scale to date.
Co-reporter:Nassiba Taleb, Victoria J. Richards, Stephen P. Argent, Joris van Slageren, William Lewis, Alexander J. Blake and Neil R. Champness
Dalton Transactions 2011 - vol. 40(Issue 22) pp:NaN5894-5894
Publication Date(Web):2011/05/04
DOI:10.1039/C1DT10057B
The synthesis, structural and magnetic characterisation of trinuclear manganese cluster, [Mn3O(O2C-anth)6(HOCH3)3] 1 (where O2C-anth = 9-anthracenecarboxylate), with crystallographic three-fold (C3) symmetry, are described. The cluster was prepared by a carboxylate exchange reaction between HO2C-anth and [Mn12O12(O2CMe)16(H2O)4] with concomitant fragmentation of the dodecanuclear Mn core of the starting material to form a trinuclear Mn3(μ3-O) cluster capped by six carboxylate ligands. Bond valence sum calculations and SQUID magnetometric measurements establish the oxidation states of the metal ions as MnII·2 MnIII which are antiferromagnetically coupled.
Co-reporter:Timothy L. Easun, Junhua Jia, Thomas J. Reade, Xue-Zhong Sun, E. Stephen Davies, Alexander J. Blake, Michael W. George and Neil R. Champness
Chemical Science (2010-Present) 2014 - vol. 5(Issue 2) pp:NaN544-544
Publication Date(Web):2013/12/06
DOI:10.1039/C3SC52745J
A metal-bearing coordination network synthesised from Re(2,2′-bipyridine-5,5′-dicarboxylate)(CO)3Cl bridging ligands and Cu(II) nodes, [{Cu(DMF)(H2O)[LRe(CO)3Cl]}·DMF]∞ReCu, undergoes an irreversible photoinduced charge transfer process. We demonstrate using time-resolved IR spectroscopy the nature of this photoinduced process and how, under suitable conditions, it is possible to initiate irreversible modification of the crystal through induction of the charge transfer process. As a result we are able to use the photoinduced process, which arises purely as a result of the structure of the coordination network, to write on crystals.
Co-reporter:Junhua Jia, Harprit Singh Athwal, Alexander J. Blake, Neil R. Champness, Peter Hubberstey and Martin Schröder
Dalton Transactions 2011 - vol. 40(Issue 45) pp:NaN12349-12349
Publication Date(Web):2011/10/25
DOI:10.1039/C1DT10901D
Reaction of Co(NO3)2·6H2O with H2L [H2L = pyridine-4-(phenyl-3′,5′-dicarboxylic acid)] under different reaction conditions gives three closely-related metal–organic framework polymers, {[Co2(L)2(DMF)]·n(solv)}∞ (1), {[Co(L)]·2DMF}∞ (2) and {[Co3(L)3(DMF)0.5(H2O)1.5]·n(solv)}∞ (3). Variation in reaction conditions thus has a decisive impact on the materials isolated, producing frameworks based upon either binuclear (1, 2) or trinuclear (3) cobalt cluster nodes. Analysis of their crystal structures shows that all three contain considerable solvent-accessible volumes, an indication of porosity that is confirmed for desolvated 1 and 3, which can store up to 2.75 and 2.33 wt% of H2 at 78 K and 20 bar, respectively.
Co-reporter:Ben A. Llewellyn, Anna G. Slater, Gudrun Goretzki, Timothy L. Easun, Xue-Zhong Sun, E. Stephen Davies, Stephen P. Argent, William Lewis, Andrew Beeby, Michael W. George and Neil R. Champness
Dalton Transactions 2014 - vol. 43(Issue 1) pp:NaN94-94
Publication Date(Web):2013/09/27
DOI:10.1039/C3DT50874A
The synthesis and photophysical study of a perylene diimide (PDI) functionalised with platinum acetylide units of the type, trans{–CC–Pt(PBu3)2–CC–Ph} and comparison with a phenylacetylide substituted model compound are reported. The model compound demonstrates typical perylene absorption and photoluminescence spectra characteristic of singlet excited state formation and decay. The Pt-substitution, however, appears to induce spin–orbit coupling into the chromophore and giving rise to a triplet excited state which was confirmed by transient absorption measurements. This excited state is quenched by oxygen, leading to the formation of singlet oxygen in dichloromethane, recorded by time-resolved near-infrared luminescence measurements.
Co-reporter:Neil R. Champness
Dalton Transactions 2011 - vol. 40(Issue 40) pp:NaN10315-10315
Publication Date(Web):2011/09/02
DOI:10.1039/C1DT11184A
A personal perspective recognising the developments in the field of metal–organic frameworks, of where the challenges currently lie and the opportunities that are on the horizon.
Co-reporter:Chenrong Tan, Sihai Yang, Neil R. Champness, Xiang Lin, Alexander J. Blake, William Lewis and Martin Schröder
Chemical Communications 2011 - vol. 47(Issue 15) pp:NaN4489-4489
Publication Date(Web):2011/03/11
DOI:10.1039/C1CC10378D
The polyhedral complex [Cu4L(H2O)4]solv (NOTT-140) shows a 4,8-connected structure of rare scu topology comprising octahedral and cuboctahedral cages; desolvated NOTT-140a shows a total CO2 uptake of 314.6 cm3 (STP) cm−3 at 20 bar, 293 K, and a total H2 uptake of 6.0 wt% at 20 bar, 77 K.
Co-reporter:Anna G. Slater (née Phillips), Peter H. Beton and Neil R. Champness
Chemical Science (2010-Present) 2011 - vol. 2(Issue 8) pp:NaN1448-1448
Publication Date(Web):2011/06/13
DOI:10.1039/C1SC00251A
Self-assembly of two-dimensional supramolecular arrays on surfaces represents a significant challenge to chemists, materials scientists and physicists. This article highlights advances in using supramolecular interactions, particularly hydrogen bonding, to self-assemble such two-dimensional arrays on surfaces. Scanning-probe microscopies, particularly scanning tunnelling microscopy (STM), can be used to determine the precise molecular arrangement of the self-assembled structures allowing insight into the self-assembly process at the molecular level. The use of such supramolecular assemblies to trap guest species, mimicking host–guest chemistry in the solution phase, will also be discussed. Such images provide great insight into the advantages and restrictions of working in two dimensions in comparison to the solution phase or the solid state.
Co-reporter:Victoria J. Richards, Stephen P. Argent, Adam Kewley, Alexander J. Blake, William Lewis and Neil R. Champness
Dalton Transactions 2012 - vol. 41(Issue 14) pp:NaN4026-4026
Publication Date(Web):2012/02/03
DOI:10.1039/C2DT12055K
Five new metal–organic frameworks prepared from the ligand 5-bis(3-(1-imidazolyl)propylcarbamoyl)terephthalate (bipta2−) and transition metal salts, Zn2+ (1), Co2+ (2), Mn2+ (3, 4) and Cu2+ (5), are reported. Single crystal X-ray studies reveal that the bipta2− ligand acts as a tetradentate ligand and combines with four-coordinate cationic metal nodes to give four-connected framework structures. Whilst reaction of bipta2− with Zn(II) gives rise to a framework of diamondoid topology 1, the analogous frameworks with Co(II), Mn(II) and Cu(II) afford frameworks that incorporate square-planar nodes. Whereas 2 and 5 form frameworks of Cd(SO4) (cds) and square 44 nets (sql), respectively, reaction of Mn(II) with bipta2− forms two supramolecular isomers of topology cds for 3 and sql for 4.
Co-reporter:Wenbin Yang, Xiang Lin, Junhua Jia, Alexander J. Blake, Claire Wilson, Peter Hubberstey, Neil R. Champness and Martin Schröder
Chemical Communications 2008(Issue 3) pp:NaN361-361
Publication Date(Web):2007/11/09
DOI:10.1039/B712201B
A biporous three dimensional (3,6)-connected coordination framework is reported which exhibits excellent H2 adsorption at low pressures (≤1 bar) with high H2 adsorption density.
Co-reporter:Minna T. Räisänen, Anna G. Slater (née Phillips), Neil R. Champness and Manfred Buck
Chemical Science (2010-Present) 2012 - vol. 3(Issue 1) pp:NaN92-92
Publication Date(Web):2011/10/04
DOI:10.1039/C1SC00543J
1,7-Diadamantanethioperylene-3,4:9,10-tetracarboxylic diimide, (Ad-S)2–PTCDI, adsorbed on Au(111) from solution was investigated by scanning tunneling microscopy (STM) and X-ray photoelectron spectroscopy (XPS). (Ad-S)2–PTCDI forms a well-ordered monolayer whose structure is described by a (2√63 × √19)R19.1° chiral unit cell containing four molecules. Codeposition of (Ad-S)2–PTCDI with 1,3,5-triazine-2,4,6-triamine (melamine) yields a honeycomb network whose (7√3 × 7√3)R30° unit cell is identical to the unsubstituted PTCDI/melamine analogue. The effect of the adamantyl thioether moieties on the adsorption of guest molecules is investigated using adamantane thiol and C60. While the thioether units do not affect the packing of adamantane thiol molecules a pronounced influence is seen in the case of fullerene. Pore modification involving different combinations of enantiomers of (Ad-S)2–PTCDI give rise to distinctly different arrangements of C60 molecules. The diversity of patterns is further increased by the presence of unsubstituted PTCDI molecules.
Co-reporter:David J. Smith, Alexander J. Blake, Claire Wilson and Neil R. Champness
Dalton Transactions 2011 - vol. 40(Issue 45) pp:NaN12264-12264
Publication Date(Web):2011/09/08
DOI:10.1039/C1DT10815H
Three CuI complexes of diimine-bearing macrocyclic ligands are described. Reaction of CuI with macrocycles of different ring size gives rise to differing degrees of aggregation of (CuI)n in the solid state. X-Ray diffraction studies reveal that whereas macrocycles with smaller ring sizes give rise to simple mononuclear CuI diimine complexes, a macrocycle of larger ring size affords a dinuclear (CuI)2 moiety, encompassed within the ligand ring. Thus, the macrocycle can be seen to determine the extent of CuI aggregation in the solid state.
Co-reporter:Anna G. Phillips, Luís M. A. Perdigão, Peter H. Beton and Neil R. Champness
Chemical Communications 2010 - vol. 46(Issue 16) pp:NaN2777-2777
Publication Date(Web):2010/02/25
DOI:10.1039/B926824C
A unimolecular hydrogen-bonded network is formed by a perylene-diimide derivative following surface self-assembly leading to the formation of pores of appropriate dimensions to accommodate regularly spaced guest C60 molecules.
Co-reporter:Neil R. Champness
Chemical Communications 2013 - vol. 49(Issue 4) pp:NaN333-333
Publication Date(Web):2012/10/29
DOI:10.1039/C2CC36098E
In 1994 the field of coordination frameworks was still in its infancy and yet to give birth to its offspring research field of metal–organic frameworks (MOFs). Studies by Zaworotko and Ciani served to illustrate both the simplicity and the complexity of these remarkable structures.
Co-reporter:Victoria J. Richards, Alexandra L. Gower, Jasper E. H. B. Smith, E. Stephen Davies, Dorothée Lahaye, Anna G. Slater, William Lewis, Alexander J. Blake, Neil R. Champness and Deborah L. Kays
Chemical Communications 2012 - vol. 48(Issue 12) pp:NaN1753-1753
Publication Date(Web):2012/01/03
DOI:10.1039/C2CC16047A
The redox processes associated with BODIPY analogues are studied by electrochemical and spectroscopic methods revealing a characteristic profile for the persistent BODIPY radical and quenching of fluorescence upon reduction.
Co-reporter:Anna G. Slater, Ya Hu, Lixu Yang, Stephen P. Argent, William Lewis, Matthew O. Blunt and Neil R. Champness
Chemical Science (2010-Present) 2015 - vol. 6(Issue 2) pp:NaN1569-1569
Publication Date(Web):2014/12/11
DOI:10.1039/C4SC03531C
The synthesis and surface-based self-assembly of thymine-functionalised porphyrins is described. Reaction of 1-formylphenyl-3-benzoyl-thymine with suitable pyrollic species leads to the formation of tetra-(phenylthymine)porphyrin (tetra-TP) or mono-thymine-tri-(3,5-di-tert-butylphenyl)porphyrin (mono-TP). Single crystal X-ray diffraction studies demonstrate the self-association of mono-TP in the solid state through thymine⋯thymine hydrogen-bonding interactions but in solution this interaction (Kd = 6.1 ± 3.0 M−1) is relatively weak in comparison to the heteromolecular interaction between mono-TP and 9-propyladenine (K = 91.8 ± 20.5 M−1). STM studies of the tetratopic hydrogen-bonding tecton, tetra-TP, deposited on an HOPG substrate reveal the formation of an almost perfectly square self-assembled lattice through thymine⋯thymine hydrogen-bonding. Co-deposition of tetra-TP with 9-propyladenine leads to the adoption of preferable thymine⋯adenine interactions leading to the formation of a heteromolecular tetra-TP⋯9-propyladenine hydrogen bonded array including both Watson–Crick thymine⋯adenine interactions and adenine⋯adenine hydrogen-bonding. The studies demonstrate a pathway for the self-assembly of tetratopic hydrogen-bonding tectons and the use of preferential heteromolecular thymine⋯adenine interactions for the disruption of the homomolecular tetra-TP array. Studies of the self-assembly of tetra-TP and 9-propyladenine demonstrate a strong dependence on overall concentration and molar ratio of components indicating the importance of kinetic effects in surface self-assembly processes.
Co-reporter:Ben A. Llewellyn, E. Stephen Davies, Constance R. Pfeiffer, Mick Cooper, William Lewis and Neil R. Champness
Chemical Communications 2016 - vol. 52(Issue 10) pp:NaN2102-2102
Publication Date(Web):2015/12/15
DOI:10.1039/C5CC09962E
A synthetic strategy involving a combination of tetra-thionation and amine substitution in the bay region of a perylene diimide (PDI) leads to remarkable examples of neutral PDIs with intense absorption maxima in the near infrared. Generation of the corresponding monoanions red shifts the absorption profile to give short-wavelength infrared bands.
Co-reporter:Ilich A. Ibarra, Sihai Yang, Xiang Lin, Alexander J. Blake, Pierre J. Rizkallah, Harriott Nowell, David R. Allan, Neil R. Champness, Peter Hubberstey and Martin Schröder
Chemical Communications 2011 - vol. 47(Issue 29) pp:NaN8306-8306
Publication Date(Web):2011/06/20
DOI:10.1039/C1CC11168J
The metal–organic frameworks NOTT-400 and NOTT-401, based on a binuclear [Sc2(μ2-OH)(O2CR)4] building block, have been synthesised and characterised; the desolvated framework NOTT-401a shows a BET surface area of 1514 m2 g−1 with a total H2 uptake of 4.44 wt% at 77 K and 20 bar.
![[1,1':3',1'':3'',1'''-Quaterphenyl]-4,4'''-dicarboxylic acid, 5',5''-bis(4-carboxyphenyl)-](/data/chemimg/3716000/1383925-31-2.png)
![[1,1':3',1'':3'',1'''-Quaterphenyl]-4,4'''-dicarboxylic acid, 5',5''-bis(4-carboxyphenyl)-](/data/chemimg/3716000/1383925-31-2_b.png)
![[1,1':4',1''-Terphenyl]-3,3'',5,5''-tetracarboxylic acid, 2',3',5',6'-tetrafluoro-](/data/chemimg/3714600/1119196-00-7.png)
![[1,1':4',1''-Terphenyl]-3,3'',5,5''-tetracarboxylic acid, 2',3',5',6'-tetrafluoro-](/data/chemimg/3714600/1119196-00-7_b.png)
![[1,1':4',1''-Terphenyl]-3,3'',5,5''-tetracarboxylic acid, 2',3',5',6'-tetramethyl-](/data/chemimg/3714600/1119195-99-1.png)
![[1,1':4',1''-Terphenyl]-3,3'',5,5''-tetracarboxylic acid, 2',3',5',6'-tetramethyl-](/data/chemimg/3714600/1119195-99-1_b.png)
![Pyridine, 2-[[4-(4-pyridinyl)phenyl]ethynyl]-](http://img.cochemist.com/ccimg/552300/552272-74-9.png)
![Pyridine, 2-[[4-(4-pyridinyl)phenyl]ethynyl]-](http://img.cochemist.com/ccimg/552300/552272-74-9_b.png)
![Pyridine, 4-[4-(4-pyridinylethynyl)phenyl]- (9CI)](/data/chemimg/3115900/241481-88-9.png)
![Pyridine, 4-[4-(4-pyridinylethynyl)phenyl]- (9CI)](/data/chemimg/3115900/241481-88-9_b.png)
![5H-Cyclopenta[d]pyridazine, 6,7-dihydro-1,4-di-2-pyridinyl-](http://img.cochemist.com/ccimg/125300/125256-65-7.png)
![5H-Cyclopenta[d]pyridazine, 6,7-dihydro-1,4-di-2-pyridinyl-](http://img.cochemist.com/ccimg/125300/125256-65-7_b.png)
![PYRIDINE, 2-[4-(4-PYRIDINYLETHYNYL)PHENYL]-](http://img.cochemist.com/ccimg/552300/552272-75-0.png)
![PYRIDINE, 2-[4-(4-PYRIDINYLETHYNYL)PHENYL]-](http://img.cochemist.com/ccimg/552300/552272-75-0_b.png)
![BENZO[G]QUINOXALINE-2,3-DIONE, 1,4-DIHYDRO-, TRIHYDRATE](http://img.cochemist.com/ccimg/864700/864677-83-8.png)
![BENZO[G]QUINOXALINE-2,3-DIONE, 1,4-DIHYDRO-, TRIHYDRATE](http://img.cochemist.com/ccimg/864700/864677-83-8_b.png)
![PHENOL, 4,4'-[2,2'-BIPYRIDINE]-6,6'-DIYLBIS-](http://img.cochemist.com/ccimg/163900/163851-03-4.png)
![PHENOL, 4,4'-[2,2'-BIPYRIDINE]-6,6'-DIYLBIS-](http://img.cochemist.com/ccimg/163900/163851-03-4_b.png)
methyl]-](http://img.cochemist.com/ccimg/177700/177609-49-3.png)
methyl]-](http://img.cochemist.com/ccimg/177700/177609-49-3_b.png)
![Ethanol,2,2'-[(1-methylethylidene)bis(4,1-phenyleneoxy-2,1-ethanediyloxy)]bis-](http://img.cochemist.com/ccimg/27700/27697-57-0.png)
![Ethanol,2,2'-[(1-methylethylidene)bis(4,1-phenyleneoxy-2,1-ethanediyloxy)]bis-](http://img.cochemist.com/ccimg/27700/27697-57-0_b.png)
![[4,4'-Bipyridine]-2-carbonitrile](http://img.cochemist.com/ccimg/137800/137787-08-7.png)
![[4,4'-Bipyridine]-2-carbonitrile](http://img.cochemist.com/ccimg/137800/137787-08-7_b.png)
![7,8-DIHYDROBENZO[PQR]TETRAPHENE](http://img.cochemist.com/ccimg/77100/77011-63-3.png)
![7,8-DIHYDROBENZO[PQR]TETRAPHENE](http://img.cochemist.com/ccimg/77100/77011-63-3_b.png)
![1,3,5,7-tetramethyl-2,4,6,8,9,10-hexathiatricyclo[3.3.1.1~3,7~]decane](http://img.cochemist.com/ccimg/6400/6327-74-8.png)
![1,3,5,7-tetramethyl-2,4,6,8,9,10-hexathiatricyclo[3.3.1.1~3,7~]decane](http://img.cochemist.com/ccimg/6400/6327-74-8_b.png)
![Benzo[lmn][3,8]phenanthroline-1,3,6,8(2H,7H)-tetrone](/data/chemimg/87700/5690-24-4.png)
![Benzo[lmn][3,8]phenanthroline-1,3,6,8(2H,7H)-tetrone](/data/chemimg/87700/5690-24-4_b.png)
![Zinc, [5,10,15,20-tetra-4-pyridinyl-21H,23H-porphinato(2-)-κN21,κN22,κN23,κN24]-, (SP-4-1)-](/data/chemimg/542300/31183-11-6.png)
![Zinc, [5,10,15,20-tetra-4-pyridinyl-21H,23H-porphinato(2-)-κN21,κN22,κN23,κN24]-, (SP-4-1)-](/data/chemimg/542300/31183-11-6_b.png)
![1,4-dihydro-Benzo[g]quinoxaline-2,3-dione](http://img.cochemist.com/ccimg/186700/186666-52-4.png)
![1,4-dihydro-Benzo[g]quinoxaline-2,3-dione](http://img.cochemist.com/ccimg/186700/186666-52-4_b.png)
![Pyridine, 4-[(4-bromophenyl)ethynyl]-](http://img.cochemist.com/ccimg/138600/138517-20-1.png)
![Pyridine, 4-[(4-bromophenyl)ethynyl]-](http://img.cochemist.com/ccimg/138600/138517-20-1_b.png)
![[2,2'-Bipyridine]-6,6'-dicarboxylic acid](/data/chemimg/52900/4479-74-7.png)
![[2,2'-Bipyridine]-6,6'-dicarboxylic acid](/data/chemimg/52900/4479-74-7_b.png)
![4-[10-(4-formylphenyl)anthracen-9-yl]benzaldehyde](http://img.cochemist.com/ccimg/324800/324750-99-4.png)
![4-[10-(4-formylphenyl)anthracen-9-yl]benzaldehyde](http://img.cochemist.com/ccimg/324800/324750-99-4_b.png)
![Anthra[2,1,9-def:6,5,10-d'e'f']diisoquinoline-1,3,8,10(2H,9H)-tetrone, 5,12-dibromo-2,9-bis(2-ethylhexyl)-](/data/chemimg/102800/851786-15-7.png)
![Anthra[2,1,9-def:6,5,10-d'e'f']diisoquinoline-1,3,8,10(2H,9H)-tetrone, 5,12-dibromo-2,9-bis(2-ethylhexyl)-](/data/chemimg/102800/851786-15-7_b.png)
![Pyrazino[2,3-f]quinoxaline](http://img.cochemist.com/ccimg/300/231-23-2.png)
![Pyrazino[2,3-f]quinoxaline](http://img.cochemist.com/ccimg/300/231-23-2_b.png)
![Anthra[2,1,9-def:6,5,10-d'e'f']diisoquinoline-1,3,8,10(2H,9H)-tetrone, 5,12-dibromo-2,9-dibutyl-](/data/chemimg/106800/861853-30-7.png)
![Anthra[2,1,9-def:6,5,10-d'e'f']diisoquinoline-1,3,8,10(2H,9H)-tetrone, 5,12-dibromo-2,9-dibutyl-](/data/chemimg/106800/861853-30-7_b.png)
![Anthra[2,1,9-def:6,5,10-d'e'f']diisoquinoline-1,3,8,10(2H,9H)-tetrone, 5,13-dibromo-2,9-bis(2-ethylhexyl)-](/data/chemimg/102800/946527-46-4.png)
![Anthra[2,1,9-def:6,5,10-d'e'f']diisoquinoline-1,3,8,10(2H,9H)-tetrone, 5,13-dibromo-2,9-bis(2-ethylhexyl)-](/data/chemimg/102800/946527-46-4_b.png)
![[4,4'-Bipyridine]-2,2',6,6'-tetracarboxylic acid](/data/chemimg/124558-60-7.png)
![[4,4'-Bipyridine]-2,2',6,6'-tetracarboxylic acid](/data/chemimg/124558-60-7_b.png)
![6,9,12,15,18,29,32,35,38,41-Decaoxapentacyclo[40.4.0.05,46.019,24.023,28]hexatetraconta-1,3,5(46),19,21,23,25,27,42,44-decaene](/data/chemimg/103300/116059-04-2.png)
![6,9,12,15,18,29,32,35,38,41-Decaoxapentacyclo[40.4.0.05,46.019,24.023,28]hexatetraconta-1,3,5(46),19,21,23,25,27,42,44-decaene](/data/chemimg/103300/116059-04-2_b.png)
