Co-reporter:Minsong Wu, Liusong Ni, Guoping Yong, Cong Zhang
Synthetic Metals 2017 Volume 228(Volume 228) pp:
Publication Date(Web):1 June 2017
DOI:10.1016/j.synthmet.2017.04.005
•New organic materials were facilely synthesized.•Novel seven-membered ring compound reveals the enhanced luminescence.•Reversible luminescent color switching in the response to acid-base vapor stimuli.•The acid-base vapor induced morphological transformation.Through simple and green strategy, we unprecedentedly synthesized a novel organic compound through methyl-directed aromatic electrophilic substitution reactions. This work indicates that only introduction of methyl group at molecular framework can construct novel seven-membered ring organic materials. Interestingly, this organic material not only reveals the enhanced luminescence, but also the reversible luminescent color (red↔green) switching in the response to acid-base vapor stimuli, which is accompanied by the reversible morphological transformation (3D microbrick↔2D hexangular microflake). The present work provides a promising approach for synthesizing organic materials and a new access to develop dynamic functional materials which can be reversibly switched between different luminescence and morphology based on external acid-base vapor stimuli.Download high-res image (168KB)Download full-size image
Co-reporter:Cong Zhang, Chen Shen and Guoping Yong
CrystEngComm 2016 vol. 18(Issue 12) pp:2041-2045
Publication Date(Web):22 Feb 2016
DOI:10.1039/C6CE00202A
Positional isomers, protonation and solvent provide useful strategies for morphology-controllable fabrication of organic microcrystals. Among them, the solvent unprecedentedly induces a globate polyhedron morphology with unusual orange-red phosphorescence. The changes in morphology also induce interesting changes in the photophysical properties of boron difluoride organic microcrystals.
Co-reporter:Chen Shen, Guo-Ping Yong, Cong Zhang and Ya Feng
RSC Advances 2016 vol. 6(Issue 12) pp:10162-10167
Publication Date(Web):19 Jan 2016
DOI:10.1039/C5RA24123E
The ability to control the morphologies and photophysical properties of organic micro/nanomaterials is of special importance. The research reported herein demonstrates a solid phase anion exchange reaction can be used as simple, low cost and green approach to tailor the morphologies of boron-difluoride complex microcrystals. The great influence of anions on the morphologies of such organic microcrystals is also discovered. The changes in morphology induce distinctive changes in the photophysical properties. Compared to one- or three-dimensional morphologies, two-dimensional hexangular microflake, rhombic and rectangle microsheet morphologies reveal higher phosphorescent quantum yields and enhanced near-infrared absorptions, which should be attributed to the morphological anisotropy of two-dimensional microsheets, demonstrating morphology-sensitive photophysical features.
Co-reporter:Cong Zhang, Ya Feng, Chen Shen, Guoping Yong
Chemical Physics Letters 2016 Volume 649() pp:97-102
Publication Date(Web):April 2016
DOI:10.1016/j.cplett.2016.02.042
Highlights
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Novel triarylmethyl carbocation radicals were facilely prepared.
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The protonation triggered conformational change.
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Conformational change induced the change in crystal structures and properties.
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Various phosphorescent properties and magnetic susceptibility data.
Co-reporter:Cong Zhang, Ya Feng, Chen Shen, Guoping Yong
Chemical Physics Letters 2016 Volume 659() pp:176-181
Publication Date(Web):16 August 2016
DOI:10.1016/j.cplett.2016.07.033
Highlights
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Novel organic crystal was facilely prepared.
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The unprecedentedly undissociated HCl hydrates at ambient condition.
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Cis-linear conformation of the water dimer without cavity confinement effect.
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The peculiar tricyclo[6.2.0.0]-type hydrogen-bonding network.
Co-reporter:Guo-Ping Yong, Chen Shen, Cong Zhang and Yu-Mei Zhao
Journal of Materials Chemistry A 2015 vol. 3(Issue 35) pp:9048-9052
Publication Date(Web):06 Aug 2015
DOI:10.1039/C5TC01770J
The vapor-solid and solid-phase anion exchange reactions provide useful strategies for the morphology-controllable fabrication of organic microcrystals. The changes in morphology induce interesting changes in the photophysical properties of organic microcrystals. Significantly, hexangular microflakes exhibit higher phosphorescence quantum yield (up to 57.5%) and enhanced near-infrared absorption.
Co-reporter:Guo-Ping Yong, Chen Shen, Ya Feng, Xue-Rui Zhang and Yu-Mei Zhao
CrystEngComm 2015 vol. 17(Issue 33) pp:6338-6345
Publication Date(Web):08 Jul 2015
DOI:10.1039/C5CE00172B
Through a simple and mild approach, we unprecedentedly synthesized three novel triarylmethyl carbocation radical salts, namely bisimidazo[1,2-a]pyridin-2-one-yl(2-pyridyl)methyl carbocation radical salt (1), bisimidazo[1,2-a]pyridin-2-one-yl(3-pyridyl)methyl carbocation radical salt (2), and bisimidazo[1,2-a]pyridin-2-one-yl(4-pyridyl)methyl carbocation radical salt (3). Single-crystal X-ray diffraction analyses reveal that 1, 2 and 3 are positional isomers with different one-dimensional (1D) chain structures. Through supramolecular interactions, the 1D chains of 1 are further assembled into a 1D double-stranded chain, then into a two-dimensional (2D) layer structure, and the 1D chains of 2 and 3 are also assembled into 2D layer structures. This work indicates that the positional isomeric effects of pyridyl groups in the three carbocation radical salts are significant in the construction of isomers, because 1, 2 and 3 were synthesized and crystallized under the same conditions. Furthermore, these positional isomers exhibit different magnetic susceptibility values at 300 K. 1 with 1D double-stranded chains consists of one repetitive unit having four carbocation radical moieties, giving a magnetic susceptibility value of 1.636 emu K Oe−1 mol−1 at 300 K. 2 with 1D chains consists of one repetitive unit with two carbocation radical moieties, giving a magnetic susceptibility value of 0.747 emu K Oe−1 mol−1 at 300 K. 3 exhibits a magnetic susceptibility value of 0.326 emu K Oe−1 mol−1 for one isolated spin of the carbocation radical. Compared with 2 and 3, 1 shows broad and stronger NIR absorption bands from 800 nm to 1951 nm, probably ascribed to its 1D double-stranded chain structure, antiparallel arrangements of 2-pyridinium rings in the 1D chains, and/or tetra-connecting hydrogen-bonding bridge.
Co-reporter:Chen Shen, Yiman Zhang, Guoping Yong, Yumei Zhao
Journal of Molecular Structure 2015 Volume 1084() pp:340-344
Publication Date(Web):15 March 2015
DOI:10.1016/j.molstruc.2014.12.057
Co-reporter:Guo-Ping Yong, Yu-Mei Zhao and Ya Feng
Journal of Materials Chemistry A 2014 vol. 2(Issue 12) pp:2228-2234
Publication Date(Web):13 Jan 2014
DOI:10.1039/C3TC32130D
The reversible switching of properties for organic materials is an attractive field for both fundamental research and practical application. We report herein a novel class of organic radicals, which exhibits the reversible magnetic behavior or color switching in response to acid–base stimuli. The reversibly switchable behaviors are ascribed to the proton-triggered molecular structure and conformation conversions. The responsive dynamic magnetic properties are unique in terms of the acid–base vapor stimuli. The present work provides new access to develop dynamic multifunctional materials which can be reversibly switched between different colors or magnetic behaviors based on external stimuli.
Co-reporter:Yumei Zhao, Guoping Yong, Xuerui Zhang, Bei Zhang
Dyes and Pigments 2014 Volume 101() pp:172-178
Publication Date(Web):February 2014
DOI:10.1016/j.dyepig.2013.10.008
•3-Formyl-2,3′-biimidazo[1,2-a]pyridin-2′-ones.•A new class of phosphorescent β-cyclodextrin inclusion complexes was obtained.•The reversible dual-color switching behavior in the response to light stimuli.•The dynamic photofunctional material.We report herein two new supramolecular materials based on β-cyclodextrin inclusion complex samples with partially included organic radicals, which emit blue phosphorescence (excitation at 365 nm), and exhibit higher phosphorescent quantum yields (9.5 and 20.3%). However, purely organic radicals emit green phosphorescence, and possess low quantum yields (1.8 and 3.3%). One inclusion complex material exhibits the reversible dual-color (blue ↔ green) switching behavior in the response to ultraviolet and visible light stimuli, respectively: upon excitation with ultraviolet light (365 nm), it emits blue phosphorescence with quantum yield of 9.5%; however, it emits green phosphorescence and possesses higher quantum yield of 29.0%, upon irradiation by visible light (425 nm). The reversibly photoswitchable behavior is probably ascribed to the light-driven guest molecular conformation conversions in the β-cyclodextrin cavities. This light-responsive dual-color phosphorescent supramolecule is unique in terms of molecular conformation conversions.A novel supramolecular material based on β-cyclodextrin inclusion complexes exhibits the reversible dual-color phosphorescent switching behavior in the response to light stimuli.
Co-reporter:Yumei Zhao, Guoping Yong, Ya Feng, Chen Shen
Synthetic Metals 2014 Volume 189() pp:17-21
Publication Date(Web):March 2014
DOI:10.1016/j.synthmet.2013.12.018
•A neutral radical was obtained by Cu(I) catalyzed ring-opening and coupling reaction.•The neutral radical and its sulfate salt display different phosphorescent colors.•The neutral radical itself exhibits weak antiferromagnetic behavior.•The sulfate salt radical reveals more complex magnetic behavior.A novel neutral radical was synthesized from 2,3′-biimidazo[1,2-a]pyridin-2′-one radical via Cu(I) catalyzed ring-opening and carbon–carbon coupling reactions. The neutral radical (green-yellow phosphorescence) and its sulfate salt (blue phosphorescence) display obvious different phosphorescent colors, attributable to their different electronic structures, and stacking structures as demonstrated by powder X-ray diffraction patterns. The neutral radical itself exhibits weak antiferromagnetic property. The sulfate salt radical mainly presents diamagnetism between 58 K and 380 K owing to its dimeric structure, below 58 K, it reveals complex magnetic behavior.
Co-reporter:Guo-Ping Yong, Yu-Mei Zhao, Ya Feng and Xue-Rui Zhang
Journal of Materials Chemistry A 2013 vol. 1(Issue 21) pp:3395-3398
Publication Date(Web):22 Apr 2013
DOI:10.1039/C3TC30438H
Herein, we present two new purely organic radicals which exhibit unusual stacking-induced broadband near-infrared (NIR) absorption beyond 2500 nm and deep-red phosphorescence. These interesting properties make them promising light harvesting and solid-state NIR phosphorescent materials.
Co-reporter:Guoping Yong, Xuerui Zhang, Wenlong She, Bei Zhang
Carbon 2013 Volume 55() pp:369-371
Publication Date(Web):April 2013
DOI:10.1016/j.carbon.2012.12.065
We report the easy synthesis of hydrogenated amorphous carbon using the in situ formation of benzene radicals from iodobenzene promoted by potassium metal. The benzene radical induces benzene to convert to hydrogenated amorphous carbon. The carbon produced exhibits yellow fluorescence and low-temperature ferromagnetic behavior.
Co-reporter:Guoping Yong, Yiman Zhang, Wenlong She
Materials Letters 2013 Volume 92() pp:358-360
Publication Date(Web):1 February 2013
DOI:10.1016/j.matlet.2012.10.122
We herein report two hydrochloride crystals obtained by slow diffusion of acetone into methanol solution of 2-(imidazo[1,2-a]pyridin-2-yl)-2-oxoacetic acid radical which was acidified with different concentration of hydrochloric acid. The relationship between magnetic properties and crystal-stacking structures was also investigated. 2-(Imidazo[1,2-a]pyridin-2-yl)-2-oxoacetic acid radical in two crystals mainly exists as diamagnetic dimers formed by intermolecular close contacts or supramolecular interactions, giving rise to low magnetic susceptibilities. One crystal exhibits quasi-one-dimensional columnar stacking chain and weak antiferromagnetic behavior. Another one consists of dimers assembled by supramolecular interactions (hydrogen bonds and anion–π interactions), and reveals unusual magnetic behavior.Highlights► Two hydrochloride crystals of 2-(imidazo[1,2-a]pyridin-2-yl)-2-oxoacetic acid radical were easily obtained. ► Crystals exhibit different stacking structures and anion–π interactions. ► The stacking structures or supramolecular interactions lead to interesting magnetic properties of radical materials.
Co-reporter:Bei Zhang, Guoping Yong, Yumei Zhao, Xuerui Zhang
Optical Materials 2013 Volume 36(Issue 2) pp:191-197
Publication Date(Web):December 2013
DOI:10.1016/j.optmat.2013.08.022
•2,3′-Biimidazo[1,2-a]pyridin-2′-ones.•A new class of phosphorescent β-cyclodextrin inclusion complexes was obtained.•Near-white phosphorescence was achieved by forming inclusion complex.•Inclusion complexes exhibit excitation-light-induced phosphorescent color changes.Color tuning of organic materials is attractive field for both fundamental research and practical application. We report herein two new supramolecular materials based on β-cyclodextrin inclusion complex samples with partially included organic guests, which emit dark-blue and near-white phosphorescence (excitation at 365 nm), and exhibit higher phosphorescent quantum yields (9.2–12.4%). However, purely organic molecules themselves emit green-yellow or blue phosphorescence, and possess low phosphorescent quantum yields (1.4–3.5%). The inclusion complex samples with partially included organic guests also exhibit phosphorescent color tunability which can emit dark-blue, blue, near-white or green light, when stimulated with different excitation lights. Such excitation-light-induced supramolecular phosphorescent materials are promising candidates for potential applications in the organic electronics and dynamically photofunctional materials.Graphical abstractThe β-cyclodextrin inclusion complex samples exhibit unusual excitation-light-induced phosphorescent color changes which can emit dark-blue, blue, near-white or green light, when stimulated with different excitation lights.
Co-reporter:Guoping Yong, Xuerui Zhang, Wenlong She
Dyes and Pigments 2013 97(1) pp: 65-70
Publication Date(Web):
DOI:10.1016/j.dyepig.2012.11.026
Co-reporter:Dr. Guoping Yong;Dr. Xuerui Zhang;Dr. Yumei Zhao ;Dr. Wenlong She
Chemistry – An Asian Journal 2013 Volume 8( Issue 9) pp:2182-2188
Publication Date(Web):
DOI:10.1002/asia.201300400
Abstract
Herein, we present three imidazo[1,2-a]pyridin-2(3 H)-one derivatives that are diamagnetic in solution, but paramagnetic in the solid state, possibly owing to a stacking-induced formation of phenoxide-type radicals. Notably, a larger bathochromic shift of the absorption (even up to the near- infrared region) of these three compounds was observed in the solid state than in solution, which was attributable to the ordered columnar stacking arrangements or their single-electron character as radicals in the solid state. Interestingly, compared to that in solution, (E)-3-(pyridin-4′-ylmethylene)imidazo[1,2-a]pyridine 2(3 H)-one displayed a largely red-shifted emission (centered at 660 nm, with tailing above 800 nm) in the solid state. A larger bathochromic shift (260 nm) of the emission is an indication of better order and tight stacking in the solid state, which is brought about by the rigid and polar acceptor. These three compounds also reveal different magnetic susceptibilities at 300 K, thus implying that they possess various columnar stacking structures. Most interestingly, these three radicals exhibit unusual ferromagnetic-to-antiferromagnetic phase transitions, which can be attributed to anisotropic contraction and non-uniform slippage of the columnar stacking chains.
Co-reporter:Guo-Ping Yong, Bei Zhang, Yi-Man Zhang and Guang-Shui Li
Journal of Materials Chemistry A 2012 vol. 22(Issue 27) pp:13481-13483
Publication Date(Web):06 Jun 2012
DOI:10.1039/C2JM31617J
Herein, we report a novel supramolecular phosphorescent material based on a β-cyclodextrin inclusion complex. This inclusion complex exhibits unprecedented excitation-light-responsive phosphorescent color changes, which is a promising candidate for dynamically photofunctional material.
Co-reporter:Guo-Ping Yong, Yi-Man Zhang and Wen-Long She
CrystEngComm 2012 vol. 14(Issue 11) pp:3923-3929
Publication Date(Web):12 Mar 2012
DOI:10.1039/C2CE06702A
We herein report a new electron-deficient π system, namely carboxycarbonyl substituted imidazo[1,2-a]pyridinium, which exhibits various noncovalent interactions (hydrogen bonding, anion–π and η1-type anion–π) with chloride or perchlorate anion. Crystallographic results demonstrate that the interaction types of chloride anion and π receptor systems can be tuned: from anion–π interactions (with guest methanol molecule in crystal) to η1-type anion–π interactions (without guest methanol molecule in crystal). These carboxycarbonyl substituted imidazo[1,2-a]pyridinium salts also exhibit different phosphorescent colors in the solid state induced by crystal stacking structures or anion–π interactions that can influence the charge transfer to electron-deficient carboxycarbonyl substituted imidazo[1,2-a]pyridinium. Especially, the solid phosphorescent color changes induced by anion–π interactions are very interesting. The high solubility in water makes these purely organic phosphorescent materials promising candidates for potential applications.
Co-reporter:Guoping Yong, Wenlong She, Yiman Zhang
Dyes and Pigments 2012 Volume 95(Issue 2) pp:161-167
Publication Date(Web):November 2012
DOI:10.1016/j.dyepig.2012.04.003
Phosphorescence has seldom been observed in purely organic dyes in the solution at room temperature. We herein report efficient phosphorescence in the solution from (E)-3-benzylideneimidazo[1,2-a]pyridin-2(3H)-one and its derivatives. This opens up a new class of purely organic dyes to applications in the phosphor design. In the solid state, the ordered columnar stacking arrangements, intermolecular close contacts, and lateral intermolecular hydrogen bonding interactions between neighboring columns make these luminogenic molecules highly phosphorescent at room temperature, and lead to phosphorescent color changes (from yellow in the solution to aurantiacus–red in the solid state). Here, using these luminogenic molecules, a series of new purely organic phosphors are color-tuned to emit yellow, aurantiacus, orange, nacarat and red in the solid state, which are promising candidates for potential applications in organic light-emitting diodes for display.The new organic dyes based on (E)-3-benzylideneimidazo[1,2-a]pyridin-2(3H)-one display phosphorescence in solution and yellow to red phosphorescent colors in the solid state.Highlights► (E)-3-benzylideneimidazo[1,2-a]pyridin-2(3H)-one derivatives. ► A new class of phosphorescent dyes was obtained via one-pot synthesis method. ► These dyes exhibit efficient room-temperature phosphorescence in solution. ► In the solid, some dyes display stacking-induced phosphorescent color changes. ► The phosphorescence nature is further supported by the long decay lifetimes.
Co-reporter:Guo-Ping Yong, Yi-Man Zhang and Bei Zhang
CrystEngComm 2012 vol. 14(Issue 24) pp:8620-8625
Publication Date(Web):15 Oct 2012
DOI:10.1039/C2CE26418H
A novel quinone biradical (1) was hydrothermally synthesized through ZnCl2 mediated decarboxylation and carbon–carbon coupling reactions using the 2-(imidazo[1,2-a]pyridin-2-yl)-2-oxoacetic acid radical. Interestingly, when CuCl2 was used instead of ZnCl2, a new mixed-valence copper coordination polymer (2) with semiquinone radical anion ligand was obtained. The possible formation mechanism of these two compounds is proposed. The EPR and magnetic susceptibility data suggest that 1 is a biradical. The EPR and XPS results support that 2 is a mixed-valence copper coordination polymer. The quinone biradical 1 forms a one-dimensional (1D) columnar stacking chain. The coordination polymer 2 consists of a two-dimensional (2D) layered framework constructed by 1D corrugated double-stranded stair-like inorganic [CuCl]n chains and bridged semiquinone radical anion ligands. 1 and 2 exhibit antiferromagnetic coupling interactions and different luminescent colors.
Co-reporter:Guo-Ping Yong, Ying-Zhou Li, Yi-Man Zhang and Wen-Long She
CrystEngComm 2012 vol. 14(Issue 4) pp:1439-1448
Publication Date(Web):09 Dec 2011
DOI:10.1039/C1CE05641G
The preparation, X-ray crystallography, EPR, and magnetic and luminescent properties of three new metal–anion radical frameworks are described herein. The anion radical ligand (bipo−˙) and co-ligand, 1,4-benzenedicarboxylate (BDC2−), coordinate to Cd(II) centers, leading to an interpenetrated three-dimensional (3D) metal–organic frameworks (MOF), [Cd3(bipo−˙)4(BDC)]n (1). Although [Fe3(bipo−˙)4(BDC)]n (2) and 1 possess the same space group (tetragonal, P42/nbc), and similar rigid spirocycle-like chain and powder X-ray diffraction (PXRD) patterns, 2 exhibits an interesting spirocycle-like one-dimensional (1D) chain network, in which BDC2− behaves not as bridging co-ligand but as a counteranion, according to smaller Fe(II) ion size and long Fe1⋯Fe1′ distance between rigid chains. Thus, metal ion sizes induce different networks of isomorphous 1 and 2. Moreover, the different forming mechanisms of bipo−˙ ligand also result in different structural MOFs: the in situ deprotonation of initial Hbipo−˙ leads to an 1D Fe(II) MOF (2); the in situaldol condensation and then deprotonation of initial hydrochloride salt of imidazo[1,2-a]pyridin-2(3H)-one results in a two-dimensional (2D) Fe(II) MOF, [Fe3(bipo−˙)2(μ2-OH)2(μ2-H2O)(BDC)]n (3). More noteworthy, in 2, BDC2− suffers large distortion, mainly attributed to its strong electrostatic interaction with the Fe(II) cation on the rigid spirocycle chain. Compounds 2 and 3 exhibit broad EPR signals, ascribed to the strong iron–anion radical antiferromagnetic coupling. 1 shows an unusual magnetic phase transition at ∼70 K, and intense fluorescence emission which can even be excited by visible light (460 nm). Both 2 and 3 show strong antiferromagnetic interaction between Fe(II) cation and radical. Compared to 1, two Fe(II) MOFs exhibit obvious blue-shift fluorescence emissions.
Co-reporter:Yiman Zhang, Guoping Yong, Chongfu Li, Wenlong She, Yingzhou Li
Synthetic Metals 2012 Volume 161(23–24) pp:2708-2713
Publication Date(Web):January 2012
DOI:10.1016/j.synthmet.2011.10.005
A new neutral radical was synthesized from a zwitterionic radical via radical oxidation ring-opening reaction under mild conditions. The zwitterionic radical displays interesting magnetic behavior, and it also possesses higher conductivity. The neutral radical exhibits unusual twice magnetic phase transition behaviors, including a high ferromagnetic to antiferromagnetic phase transition temperature (ca. 382 K), which can be attributed to the anisotropic contraction and non-uniform slippage of columnar stacking chain and the changes of close intermolecular contacts. These unique magnetic behaviors ascribe to their different stacking structures.Highlights► A neutral radical was obtained via ring-opening reaction of zwitterionic radical. ► Two radicals exhibit conductivities and interesting magnetic behaviors. ► The zwitterionic radical displays a reversal of the net magnetization. ► The neutral radical exhibits a peculiar twice spin transition behavior. ► The neutral radical also possesses a high magnetic phase transition temperature.
Co-reporter:Guo-Ping Yong, Yi-Man Zhang, Wen-Long She and Ying-Zhou Li
Journal of Materials Chemistry A 2011 vol. 21(Issue 46) pp:18520-18522
Publication Date(Web):28 Oct 2011
DOI:10.1039/C1JM14690D
The internal salt and the sodium salt based on a new purely organic radical material exhibit stacking-induced white-light and blue-light phosphorescence, respectively, and possess moderate quantum yields. The high solubility in water makes them promising candidates for potential applications in OLEDs, especially as white-LEDs.
Co-reporter:Guo-Ping Yong, Wen-Long She, Yi-Man Zhang and Ying-Zhou Li
Chemical Communications 2011 vol. 47(Issue 42) pp:11766-11768
Publication Date(Web):28 Sep 2011
DOI:10.1039/C1CC14420K
A stable zwitterionic radical can catalyze direct arylation of unactivated aromatic C–H bonds via a chain homolytic aromatic substitution mechanism in the presence of potassium tert-butoxide.
Co-reporter:Guo-Ping Yong, Ying-Zhou Li, Chong-Fu Li, Yi-Man Zhang and Wen-Long She
Dalton Transactions 2011 vol. 40(Issue 16) pp:4131-4139
Publication Date(Web):08 Mar 2011
DOI:10.1039/C0DT01667E
The preparation, X-ray crystallography, EPR, magnetic and luminescent investigation of new metal-anion radical framework materials based on a new anion radical ligand generated by in situ deprotonation of a stable zwitterionic radical are described herein. N,O,N-tripodal anion radical ligand (bipo−˙) links metal cations, giving rise to four isostructural one-dimensional metal–organic frameworks, [M(bipo−˙)(L)]n [M = Zn, L = HCOO− (1), SCN− (1a), N3− (1b); M = Co, L = Br− (3)]. The tripodal bipo−˙ ligand and one co-ligand, 1,4-benzenedicarboxylate, coordinate to metals leading to two isostructural two-dimensional metal–organic frameworks, [M(bipo−˙)(BDC)0.5]n [M = Zn (2) and Co (4)]. The two CoII compounds are the first examples that exhibit unusual ferromagnetic to antiferromagnetic phase transition with transition temperature over room temperature, which can be demonstrated by the cooling and warming measurements of susceptibility. Compound 4 also exhibits long-range magnetic ordering with the critical temperature at about 44 K proved by ac susceptibility measurements. The metal-radical frameworks exhibit distinctly different fluorescence emissions. Especially, the isomorphous one-dimensional ZnII compounds show interesting terminal anion ligand-induced photoluminescent color changes, including direct and invariable white-light-emission with terminal SCN− ligand.
Co-reporter:Dr. Guoping Yong;Yingzhou Li;Wenlong She ;Yiman Zhang
Chemistry - A European Journal 2011 Volume 17( Issue 44) pp:12495-12501
Publication Date(Web):
DOI:10.1002/chem.201101621
Abstract
Five phosphorescent metal–anion radical coordination polymers based on a new anion radical ligand generated by in situ deprotonation of a stable zwitterionic radical are described. The N,O,N-tripodal anion radical ligand links metal cations, which leads to five isostructural coordination polymers, [M3(bipo−.)4(L)2]n (M=Cd or Mn, Hbipo−.=2,3′-biimidazo[1,2-a]pyridin-2′-one, L=Cl−, HCOO− or SCN−). The isostructural coordination polymers exhibit novel one-dimensional spirocycle-like structures. Three isostructural CdII coordination polymers display unusual phosphorescent color changes (blue, yellow, and white) induced by terminal anions. Significantly, the CdII coordination polymer with terminal Cl− possesses moderate quantum yield, and shows a bright white-light phosphorescence emission, which is independent of excitation wavelength and can even be excited by visible light. Upon adjusting the metal cation to MnII, two isostructural MnII coordination polymers reveal deep-blue-light phosphorescence emissions that are independent of terminal anions. As radical-based coordination polymers, some of them show antiferromagnetic interactions between radical species or radical and metal center.
Co-reporter:Guo-Ping Yong, Chong-Fu Li, Ying-Zhou Li and Shi-Wei Luo
Chemical Communications 2010 vol. 46(Issue 18) pp:3194-3196
Publication Date(Web):18 Mar 2010
DOI:10.1039/B923730E
A new and stable zwitterionic (neutral) radical and its perchlorate salts exist as diamagnetic π-dimers in solution, and π-stacking 1D chains with interesting magnetic and luminescent properties in solid state.
Co-reporter:Chong-Fu Li, Guo-Ping Yong, Ying-Zhou Li
Inorganic Chemistry Communications 2010 Volume 13(Issue 1) pp:179-182
Publication Date(Web):January 2010
DOI:10.1016/j.inoche.2009.11.009
A series of iridium (III) complexes incorporating novel ancillary ligands have been synthesized and fully characterized by IR, 1H NMR, HRMS and elemental analysis. The crystal structures of 1 and 4 have been determined by X-ray analysis. The photoluminescence spectra of 1–4 show emission maxima at 501, 414, 592 and 504 nm, respectively, which cover almost the whole visible range, as a consequence of the nature of the fused imidazo-carboxylate ancillary ligands. In particular, 3 is an effective constituent for the multi-component white light phosphorescent materials, because it can simultaneously emit three colors (blue, blue–green, and red) and cover the whole visible range from 400 to 600 nm.The photoluminescence spectra of iridium (III) complexes with novel ancillary ligands cover almost the whole visible range with blue, blue–green, and red emissions.
Co-reporter:Guo-Ping Yong, Dong Tian, Hong-Wu Tong, Shao-Min Liu
Journal of Molecular Catalysis A: Chemical 2010 323(1–2) pp: 40-44
Publication Date(Web):
DOI:10.1016/j.molcata.2010.03.007
Co-reporter:Guo-Ping Yong, Shu Qiao and Zhi-Yong Wang
Crystal Growth & Design 2008 Volume 8(Issue 5) pp:1465
Publication Date(Web):April 16, 2008
DOI:10.1021/cg800025y
A one-dimensional Zn(II) radical anion coordination polymer, [ZnCl(obip•)]n (Hobip = 2,3′-biimidazo[1,2-a]pyridin-2′(3′H)-one) (1) was synthesized by a hydrothermal reaction between Zn(ClO4)2·6H2O and hydrochloride salt of imidazo[1,2-a]pyridin-2(3H)-one, in which the radical anion ligand ([obip]•−) was generated in situ by aldol condensation and then deprotonation. The compound 1 presents strong antiferromagnetic coupling between paramagnetic radical species and notable greenish yellow-red fluorescence emission.
Co-reporter:Wen-Hui Liu, Guo-Ping Yong, Li Fang, Shao-Kun Wang, Hai-Jun Bai, Jia-He Jiang and Shao-Min Liu
Journal of Agricultural and Food Chemistry 2008 Volume 56(Issue 1) pp:185-189
Publication Date(Web):November 29, 2007
DOI:10.1021/jf0722708
Although phytosterols in tobacco leaves have specific effects on tobacco quality, there is little research on the distribution of free and conjugated phytosterols in various tobacco leaves. In this paper, we explored the content and composition of phytosterols in representative cured tobacco leaves by gas chromatography of TMS-ether derivatives. We found that phytosterol contents in tobacco leaves ranged from 1.0 to 2.5 mg/g of dried leaf tissue, depending on different types of tobacco leaves. The majority of phytosterols (75–85%) were conjugated as ester and glycosides, with only about 15–25% existing in the free form. Furthermore, the genetic variability gives rise to the significant differences among different tobacco types with phytosterol levels: the contents of phytosterols in tobacco leaves decreased in the order of flue-cured tobacco, Oriental tobacco, Burley tobacco, cigar tobacco, and Maryland tobacco. At the same time, the tobacco curing process leads to a difference in phytosterol existing-form distribution in some variation laws.
Co-reporter:Liusong Ni, Chen Shen, Guoping Yong, Cong Zhang
Materials Letters (15 March 2017) Volume 191() pp:
Publication Date(Web):15 March 2017
DOI:10.1016/j.matlet.2016.12.078
•New organic microcrystals were in situ synthesized.•Organic nanowires were firstly fabricated by facile vapor-solid reaction strategy.•Organic nanowires reveal improved performance due to high aspect ratio.•The enhanced phosphorescence of ultralong nanowire materials.The development of organic micro/nanomaterials plays a major role in emerging organic optoelectronic applications. In the present work, the ultralong organic nanowires with high aspect ratio (>256) were firstly fabricated by a green vapor-solid reaction strategy. The organic nanowires reveal improved phosphorescent performance, which is attributed to high aspect ratio of nanowires, and/or morphological anisotropy of larger bundles made of nanowires. The importance of this work evidences that the vapor-solid reaction can facilely fabricate organic nanowire materials.The ultralong organic nanowires with high aspect ratio and improved phosphorescent performance were firstly fabricated by a green vapor-solid reaction strategy.
Co-reporter:Guo-Ping Yong, Wen-Long She, Yi-Man Zhang and Ying-Zhou Li
Chemical Communications 2011 - vol. 47(Issue 42) pp:NaN11768-11768
Publication Date(Web):2011/09/28
DOI:10.1039/C1CC14420K
A stable zwitterionic radical can catalyze direct arylation of unactivated aromatic C–H bonds via a chain homolytic aromatic substitution mechanism in the presence of potassium tert-butoxide.
Co-reporter:Guo-Ping Yong, Ying-Zhou Li, Chong-Fu Li, Yi-Man Zhang and Wen-Long She
Dalton Transactions 2011 - vol. 40(Issue 16) pp:NaN4139-4139
Publication Date(Web):2011/03/08
DOI:10.1039/C0DT01667E
The preparation, X-ray crystallography, EPR, magnetic and luminescent investigation of new metal-anion radical framework materials based on a new anion radical ligand generated by in situ deprotonation of a stable zwitterionic radical are described herein. N,O,N-tripodal anion radical ligand (bipo−˙) links metal cations, giving rise to four isostructural one-dimensional metal–organic frameworks, [M(bipo−˙)(L)]n [M = Zn, L = HCOO− (1), SCN− (1a), N3− (1b); M = Co, L = Br− (3)]. The tripodal bipo−˙ ligand and one co-ligand, 1,4-benzenedicarboxylate, coordinate to metals leading to two isostructural two-dimensional metal–organic frameworks, [M(bipo−˙)(BDC)0.5]n [M = Zn (2) and Co (4)]. The two CoII compounds are the first examples that exhibit unusual ferromagnetic to antiferromagnetic phase transition with transition temperature over room temperature, which can be demonstrated by the cooling and warming measurements of susceptibility. Compound 4 also exhibits long-range magnetic ordering with the critical temperature at about 44 K proved by ac susceptibility measurements. The metal-radical frameworks exhibit distinctly different fluorescence emissions. Especially, the isomorphous one-dimensional ZnII compounds show interesting terminal anion ligand-induced photoluminescent color changes, including direct and invariable white-light-emission with terminal SCN− ligand.
Co-reporter:Guo-Ping Yong, Yu-Mei Zhao, Ya Feng and Xue-Rui Zhang
Journal of Materials Chemistry A 2013 - vol. 1(Issue 21) pp:NaN3398-3398
Publication Date(Web):2013/04/22
DOI:10.1039/C3TC30438H
Herein, we present two new purely organic radicals which exhibit unusual stacking-induced broadband near-infrared (NIR) absorption beyond 2500 nm and deep-red phosphorescence. These interesting properties make them promising light harvesting and solid-state NIR phosphorescent materials.
Co-reporter:Guo-Ping Yong, Yi-Man Zhang, Wen-Long She and Ying-Zhou Li
Journal of Materials Chemistry A 2011 - vol. 21(Issue 46) pp:NaN18522-18522
Publication Date(Web):2011/10/28
DOI:10.1039/C1JM14690D
The internal salt and the sodium salt based on a new purely organic radical material exhibit stacking-induced white-light and blue-light phosphorescence, respectively, and possess moderate quantum yields. The high solubility in water makes them promising candidates for potential applications in OLEDs, especially as white-LEDs.
Co-reporter:Guo-Ping Yong, Bei Zhang, Yi-Man Zhang and Guang-Shui Li
Journal of Materials Chemistry A 2012 - vol. 22(Issue 27) pp:NaN13483-13483
Publication Date(Web):2012/06/06
DOI:10.1039/C2JM31617J
Herein, we report a novel supramolecular phosphorescent material based on a β-cyclodextrin inclusion complex. This inclusion complex exhibits unprecedented excitation-light-responsive phosphorescent color changes, which is a promising candidate for dynamically photofunctional material.
Co-reporter:Guo-Ping Yong, Chen Shen, Cong Zhang and Yu-Mei Zhao
Journal of Materials Chemistry A 2015 - vol. 3(Issue 35) pp:NaN9052-9052
Publication Date(Web):2015/08/06
DOI:10.1039/C5TC01770J
The vapor-solid and solid-phase anion exchange reactions provide useful strategies for the morphology-controllable fabrication of organic microcrystals. The changes in morphology induce interesting changes in the photophysical properties of organic microcrystals. Significantly, hexangular microflakes exhibit higher phosphorescence quantum yield (up to 57.5%) and enhanced near-infrared absorption.
Co-reporter:Guo-Ping Yong, Yu-Mei Zhao and Ya Feng
Journal of Materials Chemistry A 2014 - vol. 2(Issue 12) pp:NaN2234-2234
Publication Date(Web):2014/01/13
DOI:10.1039/C3TC32130D
The reversible switching of properties for organic materials is an attractive field for both fundamental research and practical application. We report herein a novel class of organic radicals, which exhibits the reversible magnetic behavior or color switching in response to acid–base stimuli. The reversibly switchable behaviors are ascribed to the proton-triggered molecular structure and conformation conversions. The responsive dynamic magnetic properties are unique in terms of the acid–base vapor stimuli. The present work provides new access to develop dynamic multifunctional materials which can be reversibly switched between different colors or magnetic behaviors based on external stimuli.
Co-reporter:Guo-Ping Yong, Chong-Fu Li, Ying-Zhou Li and Shi-Wei Luo
Chemical Communications 2010 - vol. 46(Issue 18) pp:NaN3196-3196
Publication Date(Web):2010/03/18
DOI:10.1039/B923730E
A new and stable zwitterionic (neutral) radical and its perchlorate salts exist as diamagnetic π-dimers in solution, and π-stacking 1D chains with interesting magnetic and luminescent properties in solid state.
![Imidazo[1,2-a]pyridin-2-ol](http://img.cochemist.com/ccimg/112600/112566-20-8.png)
![Imidazo[1,2-a]pyridin-2-ol](http://img.cochemist.com/ccimg/112600/112566-20-8_b.png)
![Imidazo[1,2-a]pyridin-2(3H)-one hydrochloride](http://img.cochemist.com/ccimg/52700/52687-85-1.png)
![Imidazo[1,2-a]pyridin-2(3H)-one hydrochloride](http://img.cochemist.com/ccimg/52700/52687-85-1_b.png)