29 results on '"Yuanyuan Fang"'
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2. Spectroelectrochemical one-electron reduction product of (TPP)Zn in nonaqueous media? Not always the expected porphyrin π-anion radical
- Author
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W. Ryan Osterloh, Yuanyuan Fang, Zhongping Ou, and Karl M. Kadish
- Subjects
General Chemistry - Abstract
Zinc tetraphenylporphyrin (TPP)Zn was examined as to its as to its electroreduction properties by cyclic voltammetry and spectroelectrochemistry in six nonaqueous solvents containing tetrabutylammonium perchlorate (TBAP). The porphyrin undergoes an initial one-electron reduction to give a [Formula: see text]-anion radical on the cyclic voltammetry timescale but the radical was not stable on the spectroelectrochemical timescale when utilizting chlorinated alkane solvents containing 0.1 M TBAP (CH2Cl2, 1-2,dichloroethane (C2H4Cl[Formula: see text] where chloride, generated from minute amounts of reduced solvent, formed an axially coordinated complex, (TPP)Zn[Formula: see text](Cl[Formula: see text], prior to reduction of the porphyrin. This spectroelectrochemically characterized product exhibits red-shifted Soret and Q-bands as compared to that of the neutral (TPP)Zn under the same solution conditions and analytical plots obtained from recording the spectrum as a function of potential rule out the possibility of forming the superoxide complex, (TPP)Zn[Formula: see text](O[Formula: see text], in chlorinated alkane solvents.
- Published
- 2022
3. Electrochemical characterization of β,β′-butanoporphyrins containing sterically hinderedmeso-2,6-dihalogenophenyl substituents and first-row transition metal ions in nonaqueous media
- Author
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Yuanyuan Fang, Zhongping Ou, Yueping Hou, Liping Wang, Karl M. Kadish, and Weijie Xu
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Steric effects ,Chemistry ,Polymer chemistry ,General Chemistry ,Electrochemistry ,Transition metal ions ,Characterization (materials science) - Abstract
Six [Formula: see text],[Formula: see text]-butano substituted metalloporphyrins containing sterically hindered meso-dihalogenophenyl substituents and first-row transition metal ions were synthesized and their electrochemical and spectroelectrochemical properties were characterized in nonaqueous media. The investigated compounds have the general formula butano(Y2Ph)4PorM, where Por is a dianion of the porphyrin, M = Mn[Formula: see text]Cl, Fe[Formula: see text]Cl, Co[Formula: see text], Ni[Formula: see text], Cu[Formula: see text] or Zn[Formula: see text]and Y2Ph is a sterically hindered 2,6-F2Ph or 2,6-Cl2Ph group on each of the four meso-positions of the macrocycle. The electrochemistry of each porphyrin was examined in CH2Cl2or pyridine containing 0.1 M tetra-[Formula: see text]-butylammonium perchlorate. The first one-electron reduction is metal-centered for the manganese(III), iron(III) and cobalt(II) porphyrins to generate the Mn(II), Fe(II) and Co(I) porphyrins, but it is porphyrin ring-centered for the other examined M(II) porphyrins to give porphyrin [Formula: see text]-anion radicals under the given solution conditions. The effect of the [Formula: see text],[Formula: see text]-butano and sterically hindered meso-Y2Ph substituents on redox potentials and electron transfer mechanisms are discussed and compared to what was previously reported for butano-substituted tetraarylporphyrins without hindered meso-substituents.
- Published
- 2021
4. Synthesis, characterization and electrocatalytic properties of bimetallic sulfides CoS/MnS/N-C for oxygen reduction in alkaline media
- Author
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Yuanyuan Fang, Ningchao Liu, Zhongping Ou, Jian Rong, Zhaoli Xue, Fengxian Qiu, and Laihai Huang
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010405 organic chemistry ,Chemistry ,Inorganic chemistry ,02 engineering and technology ,General Chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Porphyrin ,Oxygen reduction ,0104 chemical sciences ,Catalysis ,Characterization (materials science) ,chemistry.chemical_compound ,Oxygen reduction reaction ,0210 nano-technology ,Bimetallic strip - Abstract
Synthesis, characterization and oxygen reduction reaction (ORR) catalytic properties of bimetallic sulfides CoS/MnS/N-C catalyst was discussed. The catalyst was derived from a typical Co based zeolitic imidazolate framework (ZIF-67) and manganese aminoporphyrin. 5,15-Bis(4-aminophenyl)-10,20-bis(4-bromophenyl) porphyrin manganese oxoacetate loaded with ZIF-67 forms a porphyrin loaded ZIF-67. This product was then calcined at 800ˆ∘C and vulcanized with thioacetamide to obtain the bimetallic sulfide product CoS/MnS/N-C. The structure of CoS/MnS/N-C was further characterized by XRD, XPS, FESEM and HRTEM spectra which indicated a novel porous and hollow sphere structure. The electrocatalytic properties of the bimetallic material as well as its parent porphyrin and ZIF-67 were also compared in alkaline condition (0.1 M KOH) with a rotating disk electrode. The prepared catalyst CoS/MnS/N-C exhibits a higher catalytic performance than its precursors (PorMnOAc, ZIF-67 and PorMnOAc loaded ZIF-67) with almost four electron transfers under this condition.
- Published
- 2021
5. Effect of porphyrin metal center on synthesis, structure, morphology and oxygen reduction properties of porphyrin encapsulated metal organic frameworks
- Author
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Jian Rong, Zhaoli Xue, Ningchao Liu, Guoliang Zhu, Yuanyuan Fang, Zhongping Ou, Laihai Huang, and Fengxian Qiu
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Metal ,chemistry.chemical_compound ,Morphology (linguistics) ,Chemistry ,visual_art ,Polymer chemistry ,visual_art.visual_art_medium ,Oxygen reduction reaction ,Metal-organic framework ,General Chemistry ,Zeolite ,Porphyrin ,Oxygen reduction - Abstract
A series of different metal centered 5,15-Bis(4-aminophenyl)-10,20-bis(4-bromophenyl)porphyrins (PorM) where M = H2, MnOAc, FeCl, Co or Zn were synthesized, and then encapsulated in zeolite imidazole framework-8 (ZIF-8) by typical template directed strategy to generate PorM@ZIF-8 metal organic frameworks (MOFs). These composites were characterized by UV-vis, FTIR, XRD, FESEM and HRTEM methods. Each prepared PorM@ZIF-8 MOF retained the molecular structure of porphyrin and crystal structure of ZIF-8. It is clearly shown that porphyrin centered metal ions will affect MOFs morphology. Both PorH2@ZIF-8 and PorZn@ZIF-8 gave a rhombic dodecahedron, PorMnOAc@ZIF-8 gave a truncated hexagonal prism-like structure, while no specific structures were obtained for PorFeCl@ZIF-8 and PorCo@ZIF-8 due to aggregation as characterized by FESEM spectrum. Oxygen reduction catalytic ability of ZIF-8, PorM and PorM@ZIF-8 were measured in alkaline condition (0.1 M KOH) with the number of electrons transferred being [Formula: see text] = 2.20–2.60 and generating HO[Formula: see text] as the oxygen reduction product. The catalytic property slightly increased after the porphyrin was encapsulated, due possibly to the capacity limit, inappropriate molecular distance or the direction of encapsulated porphyrin molecular.
- Published
- 2020
6. Effect of fused indanedione (IND) groups and antipodal β-substituents on electrochemical properties of unsymmetrical metalloporphyrins
- Author
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Nivedita Chaudhri, W. Ryan Osterloh, Karl M. Kadish, Lei Cong, Yuanyuan Fang, and Muniappan Sankar
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Transition metal ,Chemistry ,Polymer chemistry ,Antipodal point ,General Chemistry ,Cyclic voltammetry ,Electrochemistry - Abstract
The interacting effect of fused indanedione (IND) groups and antipodal Br [Formula: see text]-substituents on the electroreduction of free-base and transition metal tetraphenylporphyrins (TPPs) are elucidated through the use of cyclic voltammetry. A systematic study of the reduction potentials for mono- and di-fused derivatives of MTPP(IND)(R)2 and MTPP(IND)2(R)2 where R = Br or H and M = Cu[Formula: see text], Ni[Formula: see text], Zn[Formula: see text] or H2 is carried out in pyridine containing 0.1 M tetrabutylammonium perchlorate (TBAP) as supporting electrolyte and demonstrates how the overall electrochemical properties of these compounds can be tuned by systematic changes in the number of meso-[Formula: see text]fused IND groups on the molecule and the presence or absence of electron-withdrawing Br [Formula: see text]-substituents. Under these solution conditions, two reversible one-electron reductions are seen for H2TPP, while three reversible reductions are obtained for H2TPP(IND) or H2TPP(IND)Br2 and four for H2TPP(IND)2Br2. Multiple reductions also occur for the other investigated mono- and di-fused metalloporphyrins. Plots of measured [Formula: see text] values for the two ring-centered reductions of compounds in a given series vs. the number of fused IND groups are linear and with slopes varying in magnitude between 15 and 230 mV/IND depending upon the product of the electron transfer (anion radical or dianion), the specific central metal ion and the presence or absence of Br substituents on the pyrrole ring opposite the fused IND group(s). It is anticipated that the information from this study can be used for predicting the reduction potentials for yet to be synthesized compounds where a specific redox reactivity is desired.
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- 2020
7. Tetra-2,3-pyrazinoporphyrazines with peripherally appended pyridine rings. 21. Mono- and pentanuclear FeII complexes: Solid state and solution studies
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Jian Rong, Maria Pia Donzello, Giulia Vozzolo, Elena Puglisi, Karl M. Kadish, Yuanyuan Fang, and Claudio Ercolani
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biology ,molecular aggregation ,010405 organic chemistry ,Chemistry ,solid state and solution properties ,Solid-state ,mono- and pentanuclear species ,General Chemistry ,010402 general chemistry ,biology.organism_classification ,01 natural sciences ,Medicinal chemistry ,electron-deficient macrocycles ,0104 chemical sciences ,Adduct ,Molecular aggregation ,FeII porphyrazines ,chemistry.chemical_compound ,adducts with N-bases ,Pyridine ,Tetra - Abstract
New Fe[Formula: see text] complexes of formula [Py8TPyzPzFe] · xH2O, its bis-pyridine adduct [Py8TPyzPzFe(py)2] · xH2O, the pentanuclear species [(MCl[Formula: see text]Py8TPyzPzFe] · xH2O (M [Formula: see text] Pd[Formula: see text], Pt[Formula: see text] and the bis-DABCO adducts [Py8TPyzPzFe(DABCO)2] · 11H2O and [(PdCl[Formula: see text]Py8TPyzPzFe(DABCO)2] · H2O (Py8TPyzPz [Formula: see text] octapyridino-tetrapyrazinoporphyrazinato dianion; DABCO [Formula: see text] 1,4-diazabiciclo[2.2.2]octane) were synthesized and characterized by elemental and thermogravimetric analysis, IR and UV-vis spectroscopy, with added studies on the starting complex [Py8TPyzPzFe] · xH2O regarding magnetic and electrochemical behavior. Clathrated water molecules are present in all compounds and have little to no effect on their physicochemical behavior as was observed for all previously reported analogs. UV-vis spectra of the mononuclear [Py8PyzPzFe] · xH2O complex in DMSO and pyridine are indicative of aggregation immediately after dissolving the compound. However, the spectra change slowly over time leading to formation of a porphyrazine species having spectral features typical of a monomer. UV-vis spectra of the parent pentanuclear [(MCl[Formula: see text]Py8TPyzPzFe] · xH2O (M [Formula: see text] Pd[Formula: see text], Pt[Formula: see text] complexes show a smaller degree of aggregation upon dissolution in DMSO or pyridine and the spectra of these solutions also change over time to those of a monomer. The presence of aggregation, spectral evolution with time and final species formed from the N-base adducts [Py8TPyzPzFe(DABCO)2] · 11H2O and [(PdCl[Formula: see text]Py8TPyzPzFe(DABCO)2] · H2O are reported and discussed.
- Published
- 2020
8. Electrochemical and spectroelectrochemical characterization of Cu(II) and Mn(III) tetrabutano- and tetrabenzoporphyrins containing sterically hindered meso -(2,6-difluorophenyl) substituents in nonaqueous media
- Author
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Weijie Xu, Karl M. Kadish, Zhongping Ou, Yuanyuan Fang, and Liping Wang
- Subjects
Steric effects ,chemistry ,Metal ions in aqueous solution ,Polymer chemistry ,chemistry.chemical_element ,General Chemistry ,Manganese ,Electrochemistry ,Copper ,Characterization (materials science) - Abstract
Four tetrabutano and tetrabenzoporphyrins containing sterically hindered meso-(2,6-difluorophenyl) substituents and copper(II) or manganese(III) central metal ions were synthesized and characterized as to their electrochemical and spectroelectrochemical properties in nonaqueous media. The copper(II) derivatives exhibit the expected two one-electron reductions to give [Formula: see text]-anion radicals and dianions in CH2Cl2. Electrochemical and spectroelectrochemical data suggest that a Cu(II) phlorin anion is generated from the doubly reduced Cu(II) butanoporphyrin and it is this species which undergoes the third reduction in pyridine. The first one-electron reduction of the Mn(III) porphyrins is metal-centered to give a Mn(II) compound, while the second and third reductions are macrocycle-centered to give Mn(II) porphyrin [Formula: see text]-anion radicals and dianions in both CH2Cl2 and pyridine. A Mn(II) phlorin anion is also generated from the Mn(II) dianion on the spectroelectrochemical timescale under the given solution conditions. The [Formula: see text],[Formula: see text]-butano and benzo groups have a significant effect on the measured redox potentials. Steric hindrance of the meso-(2,6-difluorophenyl) substituents also has an effect on the potential separation between the first two oxidations of the benzoporphyrins.
- Published
- 2019
9. Axial coordination reactions with nitrogenous bases and determination of equilibrium constants for zinc tetraarylporphyrins containing four β,β′-fused butano and benzo groups in nonaqueous media
- Author
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Songlin Xue, Liping Wang, Yuanyuan Fang, Yang Lu, Karl M. Kadish, Zhongping Ou, and Lina Ye
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chemistry.chemical_compound ,Chemistry ,Nitrogenous base ,chemistry.chemical_element ,General Chemistry ,Zinc ,Determination of equilibrium constants ,Medicinal chemistry ,Equilibrium constant - Abstract
The axial coordination properties of six zinc tetraarylporphyrins with seven different nitrogenous bases were examined in CH2Cl2 for derivatives containing four [Formula: see text],[Formula: see text]-fused butano or benzo groups and the equilibrium constants (log[Formula: see text] determined using spectral titration methods. The examined compounds are represented as butano(YPh)4PorZn and benzo(YPh)4PorZn, where Por is the porphyrin dianion and Y is a CH3, H or Cl substituent on the para-position of each meso-phenyl ring of the macrocycle. The initial four-coordinate butano- and benzoporphyrins will axially bind one nitrogenous base to form five-coordinate derivatives in CH2Cl2 and this leads to a 4–22 nm red-shift of the Soret and Q bands. The log[Formula: see text] values range from 1.98 to 4.69 for butano(YPh)4PorZn and from 3.42 to 5.36 for benzo(YPh)4PorZn, with the exact value depending upon the meso and [Formula: see text]-substituents of the porphyrin and the conjugate acid dissociation constants (p[Formula: see text] of the nitrogenous base.
- Published
- 2019
10. Electrochemistry of zinc tetraarylporphyrins containing fused butano and benzo groups. Effect of solvent and substituents on spectra, potentials and mechanism in nonaqueous media
- Author
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Jing Sun, Liping Wang, Yuanyuan Fang, Zhongping Ou, Lina Ye, Songlin Xue, and Karl M. Kadish
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Solvent ,010405 organic chemistry ,Chemistry ,Polymer chemistry ,chemistry.chemical_element ,General Chemistry ,Zinc ,010402 general chemistry ,Electrochemistry ,01 natural sciences ,Spectral line ,0104 chemical sciences - Abstract
Two series of zinc tetraarylporphyrins containing four [Formula: see text],[Formula: see text]′-pyrrole fused butano or benzo groups were synthesized and characterized as to their electrochemical and spectroelectrochemical properties in nonaqueous media. The examined compounds are represented as butano(Ar)4PorZn and benzo(Ar)4PorZn, where Por is the porphyrin dianion and Ar is a [Formula: see text]-CH3Ph, Ph or [Formula: see text]-ClPh substitutent on [Formula: see text]-positions of the macrocycle. Each Zn(II) butano- and benzoporphyrin undergoes two one-electron reductions to give a [Formula: see text]-anion radical and dianion in CH2Cl2. In contrast, three reductions were observed for the benzoporphyrin derivatives in pyridine, the third of which is assigned as electron addition to a benzophlorin anion generated from the doubly reduced benzoporphyrin. Two overlapped one-electron oxidations were observed for the butanoporphyrins in CH2Cl2, a result not previously observed for any other zinc porphyrin. The electrochemically measured HOMO-LUMO gap of the benzoporphyrins ranges from 1.89 to 1.90 V in CH2Cl2 and from 1.93 to 1.95 V in pyridine. Both values are smaller than the gaps of butanoporphyrins at 2.11-2.13 V in CH2Cl2 and 2.07.2.09 V in pyridine.
- Published
- 2018
11. Electrochemistry of N-confused inner amino-substituted free-base tetraarylporphyrins in nonaqueous media
- Author
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Yuanyuan Fang, Songlin Xue, Karl M. Kadish, Liping Wang, Lina Ye, and Zhongping Ou
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010405 organic chemistry ,chemistry.chemical_element ,Free base ,General Chemistry ,010402 general chemistry ,Electrochemistry ,01 natural sciences ,0104 chemical sciences ,chemistry.chemical_compound ,chemistry ,Group (periodic table) ,Polymer chemistry ,Carbon ,Pyrrole - Abstract
Four N-confused free-base tetraarylporphyrins containing an amino group on the inner carbon of the inverted pyrrole were synthesized and characterized as to their electrochemical and spectroelectrochemical properties in dichloromethane and N,N-dimethylformamide containing 0.1 M tetra-[Formula: see text]-butylammonium perchlorate as supporting electrolyte. The examined compounds are represented as (NH[Formula: see text](Ar)[Formula: see text]NcpH[Formula: see text], where “Ncp” is the N-confused porphyrin macrocycle and Ar is a [Formula: see text]-CH[Formula: see text]OPh, [Formula: see text]-CH[Formula: see text]Ph, Ph or [Formula: see text]-ClPh substituent on each meso-position of the macrocycle. Each porphyrin undergoes multiple irreversible reductions and oxidations. The first one-electron addition and first one-electron abstraction are located on the porphyrin [Formula: see text]-ring system to give [Formula: see text]-anion and [Formula: see text]-cation radicals with a HOMO–LUMO gap ranging from 1.21 to 1.34 V in CH[Formula: see text]Cl[Formula: see text] and 1.06 to 1.12 V in DMF. Both electrogenerated products are unstable and undergo a rapid chemical reaction to give new electroactive species which can be further reduced at more negative potentials or further oxidized at more positive potentials. The effects of the inner amino-substituent on the UV-vis spectra and electrochemical properties of the porphyrin are discussed, and comparisons made to data in the literature for both structurally related N-confused porphyrins containing an inner carbon NO[Formula: see text] group and derivatives without the inner substituent.
- Published
- 2018
12. Influence of β-octabromination on free-base triarylcorroles: Electrochemistry and protonation-deprotonation reactions in nonaqueous media
- Author
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Yuanyuan Fang, Karl M. Kadish, Yang Song, Carl C. Wamser, Abhik Ghosh, Kolle E. Thomas, Chenyi Wang, Zhongping Ou, Jan Capar, and Jeanet Conradie
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chemistry.chemical_classification ,Tris ,Base (chemistry) ,010405 organic chemistry ,Free base ,Protonation ,General Chemistry ,010402 general chemistry ,Ring (chemistry) ,Electrochemistry ,01 natural sciences ,Medicinal chemistry ,0104 chemical sciences ,chemistry.chemical_compound ,Deprotonation ,chemistry ,Corrole - Abstract
Electrochemical and acid-base properties of four free-base triarylcorroles were examined in nonaqueous media. These compounds are represented here as (tdcc)H[Formula: see text], (tpfc)H[Formula: see text], (Br[Formula: see text]tdcc)H[Formula: see text] and (Br[Formula: see text]tpfc)H[Formula: see text], where tdcc and tpfc are the trianions of tris(2,6-dichlorophenyl)corrole and tris(pentafluorophenyl)corrole, respectively. Different spectroscopic and electrochemical properties were observed for the [Formula: see text]-brominated corroles as compared to the non-brominated derivatives, due in part to the corrole ring distortion and in part to the strong electron-withdrawing properties of the Br groups. The brominated free-base corroles are easier to deprotonate than the non-brominated corroles in solution, which was confirmed by electrochemistry and spectroelectrochemistry as well as protonation/deprotonation reactions of the compounds with acid or base in PhCN. The electrochemistry of the protonated and deprotonated corroles is presented and comparisons made with previously published data for other protonated and deprotonated free-base corroles under the same solution conditions.
- Published
- 2017
13. Electrochemistry and spectroelectrochemistry of metallohexaphyrins containing bis-copper or bis-zinc central metal ions
- Author
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Karl M. Kadish, Ying Zhang, Ru Feng, Minyuan Chen, Yuanyuan Fang, and Zhongping Ou
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Horizontal scan rate ,Tetrabutylammonium perchlorate ,010405 organic chemistry ,Metal ions in aqueous solution ,Inorganic chemistry ,chemistry.chemical_element ,General Chemistry ,Zinc ,010402 general chemistry ,Electrochemistry ,01 natural sciences ,Copper ,Porphyrin ,0104 chemical sciences ,chemistry.chemical_compound ,chemistry - Abstract
Two meso-substituted bis-metallohexaphyrins were synthesized and characterized as to their electrochemical and spectroelectrochemical properties in nonaqueous media. The examined compounds are represented as HexaPyM2, where HexaPy represents an expanded macrocycle containing six pyrroles and M [Formula: see text] Cu(II) or Zn(II). Each hexaphyrin undergoes four reversible one-electron reductions and two irreversible oxidations in PhCN or CH2Cl2 containing 0.1 M tetrabutylammonium perchlorate. The HexaPyCu2 is much easier to reduce than the corresponding Cu porphyrin with the same meso-substituents and it is also easier to reduce than a structurally related Cu(II) tripyrrinone. All four reductions of HexaPyM2 are assigned as [Formula: see text]-ring centered electron transfers to give [HexaPyM2][Formula: see text], [HexaPyM2][Formula: see text], [HexaPyM2][Formula: see text] and [HexaPyM2][Formula: see text], respectively. The neutral HexaPyCu2 and HexaPyZn2 also exhibit two oxidations, both of which are irreversible at a scan rate of 0.10 V/s. The peak separation between the first one-electron addition and the first electron abstraction of HexaPyM2 ranges from 1.46 to 1.72 V. These non-thermodynamic HOMO–LUMO gaps are similar to the range of HOMO–LUMO gaps for previously characterized sapphyrins which contain five pyrrole ring in the macrocycle.
- Published
- 2017
14. Non-linear optical, electrochemical and spectroelectrochemical properties of amphiphilic inner salt porphyrinic systems
- Author
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Jean-François Nicoud, Karl M. Kadish, Frédéric Bolze, Koen Clays, Lihan Zeng, Nicolas Desbois, Yuanyuan Fang, Claude P. Gros, Yan Cui, Colin Lopez, Hoang Minh Ngo, Griet Depotter, Clément Michelin, Isabelle Ledoux, Institut de Chimie Moléculaire de l'Université de Bourgogne [Dijon] (ICMUB), Université de Bourgogne (UB)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), University of Leuven Department of Chemistry, Université Catholique de Louvain = Catholic University of Louvain (UCL), Department of Chemistry [University of Houston], University of Houston, Laboratoire de Photonique Quantique et Moléculaire (LPQM), École normale supérieure - Cachan (ENS Cachan)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), Conception et application de molécules bioactives (CAMB), Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS), 'Centre National de la Recherche Scientifique' (ICMUB) UMR CNRS 6302, Robert A. Welch Foundation (KMK) E-680, CNRS, the 'Universite de Bourgogne', 'Conseil Regional de Bourgogne' through the 3MIM integrated project ('Marquage de Molecules par les Metaux pour l'Imagerie Medicale'), Institut de Chimie Moléculaire de l'Université de Bourgogne [Dijon] ( ICMUB ), Université de Bourgogne ( UB ) -Centre National de la Recherche Scientifique ( CNRS ), Université Catholique de Louvain ( UCL ), Laboratoire de Photonique Quantique et Moléculaire ( LPQM ), École normale supérieure - Cachan ( ENS Cachan ) -CentraleSupélec-Centre National de la Recherche Scientifique ( CNRS ), Conception et application de molécules bioactives ( CAMB ), and Université de Strasbourg ( UNISTRA ) -Centre National de la Recherche Scientifique ( CNRS )
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design ,Inorganic chemistry ,Substituent ,amphiphilic inner salt ,02 engineering and technology ,010402 general chemistry ,Electrochemistry ,Photochemistry ,[ CHIM ] Chemical Sciences ,electron-accepting moieties ,01 natural sciences ,non-linear optical property ,chemistry.chemical_compound ,Amphiphile ,chromophores ,[CHIM]Chemical Sciences ,Molecule ,Chemistry ,frequency dispersion ,Second-harmonic generation ,spectroelectrochemistry ,dipolar complexes ,General Chemistry ,021001 nanoscience & nanotechnology ,Porphyrin ,Fluorescence ,0104 chemical sciences ,2nd-harmonic generation ,electrochemistry ,microscopy ,charge-transfer ,fluorescence ,Absorption (chemistry) ,hyper-rayleigh scattering ,0210 nano-technology - Abstract
Three zwitterionic meso-substituted A3B- and AB2C-porphyrins containing one sulfonato alkylpyridinium substituent and three or two alkoxy-substituted phenyl groups were synthesized in good yield and fully characterized as to their physicochemical properties by a variety of techniques. This new series of inner salt donor-acceptor meso-substituted porphyrin derivatives were prepared for possible application as amphiphilic probes for membrane insertion in the area of combined second-harmonic and two-photon fluorescence cellular microscopy. To this end, the linear and nonlinear optical properties of the compounds were characterized, together with their electrochemical and spectroelectrochemical properties in non-aqueous media. The neutral design of such molecules enabled us to determine their second order non-linear properties, both by Electric Field Induced Second Harmonic Generation and Hyper–Rayleigh Scattering. Two-photon absorption cross sections of these dyes were also measured by the two-photon induced fluorescence method. The zwitterionic nature of the inner salt results in very specific solvent-dependent redox-properties, which could be rationalized in terms of solvent-dependent ion-pairing. The overall data electrochemical and photophysical data indicates that these new porphyrinic systems should be good probes for membrane potential sensing.
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- 2016
15. Synthesis and electrochemistry of A2B type mono- and bis-cobalt triarylcorroles and their electrocatalytic properties for reduction of dioxygen in acid media
- Author
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Yue Wang, Rui Guo, Karl M. Kadish, Zhongping Ou, Yuanyuan Fang, Yang Song, and Jijun Tang
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Xanthene ,010405 organic chemistry ,Chemistry ,Substituent ,chemistry.chemical_element ,General Chemistry ,010402 general chemistry ,Photochemistry ,Electrochemistry ,01 natural sciences ,Redox ,0104 chemical sciences ,chemistry.chemical_compound ,Cyclic voltammetry ,Corrole ,Cobalt ,Acyl group - Abstract
Two A2B mono-cobalt corroles and the corresponding bis-cobalt derivatives linked by a xanthene acyl group were synthesized, characterized as to their electrochemistry and spectroelectrochemistry in nonaqueous media and then examined as catalysts for the electroreduction of O2 in 1.0 M HClO4. The investigated mono- and bis-corroles are represented as (NH2Ph)(YPh)2CorCo(PPh[Formula: see text] and [(YPh)2CorCo(PPh[Formula: see text]]2Xac, respectively, where Cor is the trianion of the corrole, Y is a CH3 or Cl substituent on the para-position of the 5- and 15-meso-phenyl rings of the macrocycle and Xac is the xanthene acyl group linking the two macrocycles in a face-to-face arrangement. The neutral compounds were characterized by cyclic voltammetry while thin-layer spectroelectrochemistry was used to elucidate UV-visible spectra of the compounds in their electrooxidized or electroreduced forms. Rotating disk and rotating ring-disk electrode measurements were also utilized to examine the electrocatalytic activity for reduction of O2 when the face-to-face corroles were adsorbed on the electrode surface in 1.0 M HClO4. The number of electrons transferred in the catalytic electroreduction of dioxygen was calculated from currents at the disk electrode using Koutecky–Levich plots. The effect of linking the two cobalt corrole macrocycles on UV-visible spectra, redox potentials and electrocatalytic activity for the reduction of dioxygen is discussed.
- Published
- 2016
16. Effect of NO2 substitution and solvent on UV-visible spectra, redox potentials and electron transfer mechanisms of copper β-nitrotriarylcorroles. Proposed electrogeneration of a Cu(I) oxidation state
- Author
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Yang Song, Bihong Li, Rui Liu, Yuanyuan Fang, Zhongping Ou, Karl M. Kadish, and Lina Ye
- Subjects
Absorption spectroscopy ,010405 organic chemistry ,Substituent ,General Chemistry ,010402 general chemistry ,Electrochemistry ,Photochemistry ,01 natural sciences ,Redox ,0104 chemical sciences ,chemistry.chemical_compound ,Electron transfer ,chemistry ,Oxidation state ,Pyridine ,Corrole - Abstract
Three copper triarylcorroles containing a [Formula: see text]-pyrrole nitro substituent were synthesized and characterized as to their spectral and electrochemical properties in nonaqueous media. The examined compounds are represented as [Formula: see text]-NO2(YPh)3CorCu, where Cor is the trianion of a triphenylcorrole and Y is a Cl, H or CH3 substituent at the para-position of the three meso-phenyl rings of the compound. The data from absorption spectra, electrochemistry and thin-layer spectroelectrochemistry are consistent with an initial assignment of Cu[Formula: see text]-Cor[Formula: see text] in CH2Cl2, DMF and pyridine and electrogeneration of a formal Cu(II) corrole with an unreduced macrocycle, represented as Cu[Formula: see text]-Cor[Formula: see text], after the first one-electron reduction in these solvents. The doubly reduced [Formula: see text]-nitrocorrole has a sharp Soret band at 439 nm and a well-defined Q-band at 611 nm in CH2Cl2. Similar absorption spectra are seen for the three examined doubly reduced nitrocorroles in DMF and pyridine, suggesting formation of a Cu(I) species with an unreduced macrocycle which is represented as Cu[Formula: see text]-Cor[Formula: see text]. Changes in redox potentials and absorption spectra of the nitrocorroles are examined as a function of solvent and substituents on the meso-phenyl rings of the compounds and comparisons are made between spectral and electrochemical data of the newly synthesized corroles and that of structurally related tetraarylcorroles lacking a [Formula: see text]-nitro group.
- Published
- 2016
17. Synthesis and electrochemistry of cobalt tetrabutanotriarylcorroles. Highly selective electrocatalysts for two-electron reduction of dioxygen in acidic and basic media
- Author
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Karl M. Kadish, Yang Song, Zhongping Ou, Rui Guo, Yuanyuan Fang, Minyuan Chen, and Jing Sun
- Subjects
010405 organic chemistry ,Chemistry ,chemistry.chemical_element ,General Chemistry ,010402 general chemistry ,Ring (chemistry) ,Electrochemistry ,Mass spectrometry ,01 natural sciences ,0104 chemical sciences ,law.invention ,Catalysis ,chemistry.chemical_compound ,Magazine ,law ,Polymer chemistry ,Organic chemistry ,Corrole ,Science, technology and society ,Cobalt - Abstract
Three [Formula: see text],[Formula: see text]-tetrabutano-substituted cobalt(III) triarylcorroles were synthesized and characterized by UV-vis, 1H NMR spectroscopy and mass spectrometry as well as electrochemistry and spectroelectrochemistry. The examined compounds are represented as butano-(YPh)3CorCo(PPh[Formula: see text], where Cor represents the core of the corrole and Y is a CH3, H or Cl group on the para-position of each meso-phenyl ring of the macrocycle. Each corrole undergoes two stepwise cobalt-centered reductions leading to formation of Co(II) and Co(I) derivatives in CH2Cl2 containing 0.1 M TBAP. Three reversible one-electron oxidations were observed within potential, ranging from 0.16 to 1.40 V in CH2Cl2. The first oxidation generates a mixture of Co(III) [Formula: see text]-cation radical and Co(IV), while the second oxidation is metal-centered to give the Co(IV) corrole. Each cobalt corrole was examined as a catalyst for electroreduction of O2 when coated on an edge-plane pyrrolytic graphite electrode in acidic and basic solutions. The results indicate that the cobalt tetrabutanotriarylcorroles can act as selective catalysts for the 2e reduction of molecular oxygen to give H2O2 as the final product under the given solution conditions.
- Published
- 2016
18. A facile synthetic route to meso-tetraaryl substituted <font>N</font>-5 sapphyrins and first single crystal X-ray analysis confirming the pyrrole inverted structure
- Author
-
Xueyan Chen, Karl M. Kadish, Yuanyuan Fang, Zhaoli Xue, Hui Wang, Guifen Lu, Wenhao Huang, Jingjing Xiao, and Zhongping Ou
- Subjects
Solvent ,Crystallography ,chemistry.chemical_compound ,Acetic acid ,Chemistry ,Yield (chemistry) ,General Chemistry ,Photochemistry ,X ray analysis ,Electrochemistry ,Single crystal ,Catalysis ,Pyrrole - Abstract
Three meso-tetraaryl substituted N -5 sapphyrins were synthesized by a facile synthetic route from the corresponding open-chain pentapyrroles in high yield using acetic acid as the solvent and catalyst. Each compound was characterized by spectroscopic and electrochemical methods and the inverted pyrrole structure was confirmed in the solid state for the first time by single crystal X-ray analysis.
- Published
- 2015
19. Spectroelectrochemical characterization of meso triaryl-substituted <font>Mn(IV)</font>, <font>Mn(III)</font> and <font>Mn(II)</font> corroles. Effect of solvent and oxidation state on UV-visible spectra and redox potentials in nonaqueous media
- Author
-
Xueyan Chen, Bingbing Gao, Bihong Li, Shi Huang, Yuanyuan Fang, Karl M. Kadish, and Zhongping Ou
- Subjects
chemistry.chemical_element ,General Chemistry ,Manganese ,Photochemistry ,Electrochemistry ,Redox ,Solvent ,Metal ,chemistry.chemical_compound ,chemistry ,Oxidation state ,visual_art ,Pyridine ,Polymer chemistry ,visual_art.visual_art_medium ,Corrole - Abstract
Two series of substituted manganese triarylcorroles were synthesized and characterized as to their electrochemical and spectroelectrochemical properties in CH 2 Cl 2, CH 3 CN and pyridine. The investigated compounds are represented as ( YPh )3 CorMn III and ( YPh )3 CorMn IV Cl , where Cor is a trianion of the corrole and Y is a Cl , F , H or CH 3 para-substituent on the three phenyl rings of the macrocycle. Each neutral Mn(III) corrole exists as a four-coordinate complex in CH 2 Cl 2 and CH 3 CN and as a five-coordinate species in pyridine. ( YPh )3 CorMn III undergoes two oxidations to stepwise generate a Mn(IV) corrole and a Mn(IV) π-cation radical. It also undergoes one reduction to generate a Mn(II) corrole in CH 2 Cl 2 or CH 3 CN . In contrast, the reduction of ( YPh )3 CorMn III leads to a Mn(III) corrole π-anion radical in pyridine. One oxidation is observed for ( YPh )3 CorMn IV Cl in CH 2 Cl 2 and CH 3 CN to generate a Mn(IV) corrole π-cation radical while Mn(III) and Mn(II) corroles are stepwise formed after reduction of the same compound. The second reduction of ( YPh )3 CorMn IV Cl in pyridine gives a Mn(III) π-anion radical as opposed to a Mn(II) corrole with an unreduced π-ring system. The neutral, reduced and oxidized forms of each corrole were characterized by electrochemistry and UV-visible spectroelectrochemistry and comparisons are made between the UV-visible spectra and redox potentials of the compounds in different central metal oxidation states. An overall reduction/oxidation mechanism in the three solvents is proposed.
- Published
- 2014
20. Meso-dichlorophenyl substituted<font>Co</font>(<font>III</font>) corrole: A selective electrocatalyst for the two-electron reduction of dioxygen in acid media, X-ray crystal structure analysis and electrochemistry
- Author
-
Zhongping Ou, Jijun Tang, Lina Ye, Karl M. Kadish, Zhaoli Xue, Yuanyuan Fang, and Minzhu Yuan
- Subjects
Crystallography ,chemistry.chemical_compound ,Rotating ring-disk electrode ,Chemistry ,Inorganic chemistry ,Linear sweep voltammetry ,General Chemistry ,Crystal structure ,Rotating disk electrode ,Corrole ,Cyclic voltammetry ,Electrocatalyst ,Monoclinic crystal system - Abstract
A cobalt(III) corrole, represented as ( Cl2Ph )3CorCo ( PPh3), where ( Cl2Ph )3Cor is the trianion of 5,10,15-tri(2,4-dichlorophenyl)corrole, was synthesized and characterized as to its electrochemical and spectroelectrochemical properties. Single-crystal structure analysis showed the corrole to be monoclinic and have a space group P21/c with α = 13.441(3), b = 28.058(6), c = 27.584(6) Å, α = 90, β = 92.75(3), γ = 90°, Mr= 1144.38, V = 1039.1(4) Å3, Z = 8, Dc= 1.463 mg/cm3, μ = 0.816, F(000) = 4644, Rint= 0.0447, R(I > 4σ(I)) = 0.0769, wR(I > 4σ(I)) = 0.2104, R( all data ) = 0.1214 and wR( all data ) = 0.2705. The compound was also examined as a catalyst for the electroreduction of dioxygen when coated on an edge-plane pyrolytic graphite electrode in 1.0 M HClO4. Cyclic voltammetry and linear sweep voltammetry with a rotating disk electrode (RDE) or a rotating ring disk electrode (RRDE) were utilized to evaluate the catalytic activity of the corrole and elucidate the products of reduction, H2O or H2O2. Analysis of the data shows exclusively a two-electron transfer process to give 100% H2O2as the product and no H2O was detectable.
- Published
- 2014
21. Redox properties of nitrophenylporphyrins and electrosynthesis of nitrophenyl-linked <font>Zn</font> porphyrin dimers or arrays
- Author
-
Nicolas Desbois, Yuanyuan Fang, Xiaoqin Jiang, Karl M. Kadish, Claude P. Gros, Zhongping Ou, and Clément Michelin
- Subjects
chemistry.chemical_compound ,chemistry ,One-electron reduction ,Phenyl group ,General Chemistry ,Conjugated system ,Electrosynthesis ,Photochemistry ,Electrochemistry ,Porphyrin ,Medicinal chemistry ,Redox ,Ion - Abstract
Five nitrophenylporphyrins were investigated as to their electrochemical properties in CH 2 Cl 2 containing 0.1 M TBAP. The investigated compounds are represented as ( NO 2 Ph )x Ph 4-x PorM , where Por represents the dianion of the porphyrin macrocycle, Ph is a phenyl group on meso-position of the macrocycle, NO 2 Ph is a meso-substituted nitrophenyl group, M = 2 H , Pd II or Zn II and x = 1 or 2. Each porphyrin undergoes an initial one electron reduction at E1/2 = -1.07 to -1.12 V where the added negative charge is almost totally localized on the meso-nitrophenyl group of the compound. This reversible reduction is then followed by one or more irreversible reductions of the nitrophenyl anion at more negative potentials which overlap with reduction of the conjugated porphyrin macrocycle. The initial one electron addition was monitored by thin-layer UV-vis spectroelectrochemistry which confirmed formation of a reduced nitrophenyl group in each case but also gave spectral evidence for a linkage of the one-electron reduction products in the case of the Zn derivatives, giving Zn porphyrin dimers or arrays which are characterized by a 14–15 nm red-shifted Soret band and two well-defined Q-bands, consistent with conversion from an unreduced four coordinate Zn II nitrophenylporphyrin to a five-coordinate Zn II complex with an unreduced porphyrin macrocycle.
- Published
- 2014
22. Synthesis, structural characterization and protonation/deprotonation of hydroxyl-substituted free-base tetraphenylporphyrins in nonaqueous media
- Author
-
Xu Cai, Guifen Lu, Zhongping Ou, Xiufeng Zhang, Yuanyuan Fang, Min Zhu, Weihua Zhu, and Karl M. Kadish
- Subjects
chemistry.chemical_compound ,Deprotonation ,Chemistry ,Tetraphenylporphyrin ,Proton NMR ,Trifluoroacetic acid ,Phenyl group ,Free base ,Protonation ,General Chemistry ,Photochemistry ,Medicinal chemistry ,Porphyrin - Abstract
A series of hydroxyl-substituted free-base tetraphenylporphyrins was synthesized and characterized by UV-vis spectroscopy, 1 H NMR and mass spectrometry. The porphyrins are represented as (HOPh) n(t BuPh )4-n PH 2, where Ph presents a phenyl group, HO and t Bu are substituents on the para-positions of the phenyl rings of the macrocycle, n = 0–4 and P represents the dianion of tetraphenylporphyrin. The UV-visible properties of each porphyrin were examined in dichloromethane (DCM), N,N′-dimethylformamide (DMF) and dimethyl sulfoxide (DMSO) before and after addition of trifluoroacetic acid (TFA) or sodium hydroxide (NaOH) to solution. Equilibrium constants for protonation ( log βn) and deprotonation [Formula: see text] of each compound were determined using standard equations. The protonations occur in a single step involving a simultaneous two proton addition at the porphyrin central nitrogens. The phenolic protons on (HOPh) n(t BuPh )4-n PH 2 are easier to deprotonate than the core nitrogen protons of the porphyrins and this reaction occurs in a single step involving the simultaneous loss of 1–4 protons on the hydroxyl groups followed by a loss of two protons from the central nitrogens. The effect of HO substituents on UV-visible spectra and the magnitude of the protonation/deprotonation constants ( log βn and [Formula: see text]) are discussed. Two of the porphyrins, (t BuPh )4 PH 2 and trans- (HOPh) 2(t BuPh )2 PH 2, are also characterized by a single-crystal X-ray analysis.
- Published
- 2013
23. Electrochemical and spectroelectrochemical studies of β-phosphorylated <font>Zn</font> porphyrins
- Author
-
Karl M. Kadish, Yuanyuan Fang, Ping Chen, Roger Guilard, Aslan Yu. Tsivadze, Alla Bessmertnykh-Lemeune, Yulia Yu. Enakieva, Yulia G. Gorbunova, Department of Chemistry [University of Houston], University of Houston, A.N. Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences [Moscow] (RAS), Institut de Chimie Moléculaire de l'Université de Bourgogne [Dijon] (ICMUB), and Université de Bourgogne (UB)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)
- Subjects
010405 organic chemistry ,Supporting electrolyte ,Dimer ,Substituent ,chemistry.chemical_element ,General Chemistry ,Zinc ,010402 general chemistry ,Photochemistry ,01 natural sciences ,Porphyrin ,Redox ,0104 chemical sciences ,chemistry.chemical_compound ,Radical ion ,chemistry ,Polymer chemistry ,Tetrabutylammonium hexafluorophosphate ,[CHIM]Chemical Sciences ,ComputingMilieux_MISCELLANEOUS - Abstract
The electrochemical and spectroelectrochemical properties of two β-phosphorylated Zn porphyrins, [2-diethoxyphosphoryl-5,10,15,20-tetraphenylporphyrinato]zinc (1) and [2-diisopropoxyphosphoryl-5,10,15,20-tetraphenylporphyrinato]zinc (2), are reported in CH 2 Cl 2 and PhCN containing tetrabutylammonium perchlorate (TBAP) or tetrabutylammonium hexafluorophosphate (TBAPF6) as supporting electrolyte. Under certain solution conditions, three one-electron reductions are observed, with the last process being attributed to the product of a chemical reaction following formation of the porphyrin dianion. Two or three oxidations are observed for the same compounds, again depending upon the solution conditions. In some cases, two well-defined and well-separated one electron oxidations are observed but in others the first one-electron abstraction to give the porphyrin radical cation is split into two redox processes, separated from each other by 110–140 mV. This splitting of the first oxidation into two processes is attributed to linking of the two porphyrins which results when a P = O unit of the phosphoryl substituent on one porphyrin binds to the Zn ( II ) center of a second porphyrin, resulting in dimer formation. The interaction between the two macrocycles is discussed in terms of the difference in potentials between the two split redox processes (ΔE1/2) and the overall data is compared with that for other porphyrin dimers and bis-macrocycles reported in the literature.
- Published
- 2013
24. β-Nitro-substituted free-base, iron(III) and manganese(III) tetraarylporphyrins: synthesis, electrochemistry and effect of the<font>NO</font>2substituent on spectra and redox potentials in non-aqueous media
- Author
-
Karl M. Kadish, Deying Meng, Shuibo Yang, Bin Sun, Zhongping Ou, Yuanyuan Fang, and Guifen Lu
- Subjects
Substituent ,chemistry.chemical_element ,Free base ,General Chemistry ,Manganese ,Electrochemistry ,Photochemistry ,Redox ,Medicinal chemistry ,Electron transfer ,chemistry.chemical_compound ,chemistry ,Tetraphenylporphyrin ,Nitro - Abstract
Two free-base and four metal derivatives of substituted tetraarylporphyrins containing a nitro-substituent on the β-pyrrole position of the macrocycle were synthesized and characterized by UV-vis, FTIR,1H NMR and mass spectrometry as well as electrochemistry and spectroelectrochemistry in non-aqueous media. The porphyrins are represented as ( NO2TmPP ) M and ( NO2TdmPP ) M , where M = 2 H , FeIIICl or MnIIICl , m is a CH3group on the para-position of the four meso-phenyl rings of the tetraphenylporphyrin (TPP) and dm represents two OCH3substituents on the meta-positions of each phenyl ring of the TPP macrocycle. UV-visible spectra of the nitro-substituted porphyrins exhibit absorption bands which are red-shifted by 4–11 nm as compared to bands of the same substituted tetraarylporphyrins lacking a nitro substituent. Three or four reductions are observed for each iron and manganese nitroporphyrin, the first of which is metal-centered, leading to formation of an Fe ( II ) or Mn ( II ) complex. Further reduction at the metal center occurs for the iron porphyrins but this reaction proceeds via an Fe ( II ) π anion radical in the case of the two nitro-substituented derivatives. The β-nitro-substituted porphyrins are easier to reduce and harder to oxidize than the corresponding compounds lacking a nitro group. The effect of NO2substituent on reduction/oxidation potentials and the site of electron transfer was also discussed.
- Published
- 2013
25. Synthesis, characterization and solvent/structural effects on spectral and redox properties of cobalt triphenylcorroles in nonaqueous media
- Author
-
Aixiang Lü, Guifen Lu, Shi Huang, Zhongping Ou, Yuanyuan Fang, and Karl M. Kadish
- Subjects
Solvent ,Perchlorate ,chemistry.chemical_compound ,Electron transfer ,Chemistry ,Substituent ,General Chemistry ,Corrole ,Triphenylphosphine ,Photochemistry ,Redox ,Dichloromethane - Abstract
Five cobalt(III) triphenylcorroles with different electron-withdrawing or electrondonating substituents and an axially bound triphenylphosphine ligand were synthesized and characterized by spectroscopic and electrochemical techniques. The investigated compounds are represented as (4-XPh)3CorCo(PPh3), where Ph3Cor is the trianion of a triphenylcorrole and X is a OMe , Me , H , F or Cl substituent on the meso-phenyl rings. Each corrole was examined by UV-vis, 1H NMR and IR spectroscopy, mass spectrometry, electrochemistry and thin-layer spectroelectrochemistry. Redox potentials and spectra of each oxidized and reduced species were examined in dichloromethane and N,N′-dimethylformamide containing 0.1 M tetra-n-butylammonium perchlorate. Each Co(III) corrole undergoes up to five one-electron transfer reactions, some of which are reversible and others which are not. The CoIII/CoII process is irreversible in both solvents due to the loss of the triphenylphosphine axial ligand following electron transfer. The CoII/CoI process is reversible in DMF but irreversible in CH2Cl2 due to a homogenous chemical reaction between the electrogenerated Co(I) corrole and the chlorinated solvent. The potential for the first oxidation of the investigated corroles varies little with change of solvent, consistent with the lack of solvent binding to the neutral and singly oxidized forms of (4-XPh)3CorCo(PPh3). However, a single DMF molecule strongly binds to the doubly oxidized corrole in DMF or DMF/ CH2Cl2 mixtures. This results in an easier oxidation and a negative shift of ~200 mV in E1/2 upon going from CH2Cl2 to DMF as solvent. The effect of substitutents and solvent on redox potentials is discussed and an overall electroreduction/electrooxidation mechanism is proposed
- Published
- 2012
26. Electrochemistry of mono- and bis-porphyrins containing a β,β′-fused tetraazaanthracene group
- Author
-
Weihua Zhu, Zhongping Ou, Paul J. Sintic, Maxwell J. Crossley, Karl M. Kadish, and Yuanyuan Fang
- Subjects
Supporting electrolyte ,Inorganic chemistry ,General Chemistry ,Electrochemistry ,Porphyrin ,Medicinal chemistry ,Redox ,Metal ,chemistry.chemical_compound ,Perchlorate ,Quinoxaline ,chemistry ,visual_art ,Pyridine ,visual_art.visual_art_medium - Abstract
Electrochemical and thin-layer spectroelectrochemical properties of mono- and bis-porphyrins containing a β,β′-fused tetraazaanthracene (TA) group were examined in CH2Cl2, PhCN and pyridine containing 0.1 M tetra-n-butylammonium perchlorate as supporting electrolyte. The investigated mono-porphyrins are represented as (PTA)M, where M = 2H, Cu(II) or Zn(II) and PTA = the dianion of 5,10,15,20-tetrakis-(3,5-di-tert-butylphenyl)-6′,7′-dimethyl-1′,4′,5′,8′-tetraazaanthraceno-[2′,3′b]-porphyrin, while the bis-porphyrins are represented by M(P)-TA-(P)M, where M is H2, Cu(II) , Zn(II) , Ni(II) or Pd(II) and P is the dianion of 5,10,15,20-tetrakis-(3,5-di-tert-butylphenyl)porphyrin. The effect of the fused TA group on the redox potentials and UV-visible spectra of the neutral, electroreduced and electrooxidized porphyrins is discussed and the data compared to what is observed for related mono- and bis-quinoxalinoporphyrins of the type (PQ)M and (QPQ)M, where Q is a β,β′-fused quinoxaline group. Each TA-linked bis-porphyrin exhibits a strong interaction between the two equivalent porphyrin macrocycles, the magnitude of which is dependent upon the specific metal ion.
- Published
- 2012
27. Dioxygen reduction catalyzed by substituted iron tetraphenylporphyrins in acidic media
- Author
-
Karl M. Kadish, Zhongping Ou, Yuanyuan Fang, Aixiang Lü, Min Zhu, and Shi Huang
- Subjects
chemistry.chemical_compound ,chemistry ,Rotating ring-disk electrode ,Tetraphenylporphyrin ,Linear sweep voltammetry ,O2 reduction ,General Chemistry ,Rotating disk electrode ,Cyclic voltammetry ,Photochemistry ,Porphyrin ,Medicinal chemistry ,Catalysis - Abstract
Five iron tetraphenylporphyrins including the (TPP)FeCl and its derivatives which contain electron-withdrawing or electron-donating substituents on the meso-phenyl rings of the porphyrin macrocycle were examined as catalysts for the electoreduction of dioxygen in 1.0 M HClO4. The investigated compounds are represented as ( T p RPP ) FeCl , where T p RPP is the dianion of the para-substituted tetraphenylporphyrin and R = NEt2, OMe , H , Br or CF3. Cyclic voltammetry and linear sweep voltammetry at a rotating disk electrode (RDE) or a rotating ring disk electrode (RRDE) were utilized to examine the catalytic activity of the compounds. The number of electrons transferred and the percentage of H2O2produced as the product of O2electroreduction were calculated. The investigated iron porphyrins containing electron-withdrawing substituents ( R = Br and CF3) were shown to be more efficient catalysts for O2reduction than the compounds having electron-donating groups ( R = NEt2and OMe ) on the four phenyl rings of the porphyrin macrocycle.
- Published
- 2012
28. Synthesis and electrochemical properties of meso-phenyl substituted copper corroles: Solvent effect on copper oxidation state
- Author
-
Xuelin Ji, Weihua Zhu, Yuanyuan Fang, Guifen Lu, Zhongping Ou, and Wensheng Lin
- Subjects
Inorganic chemistry ,chemistry.chemical_element ,General Chemistry ,Crystal structure ,Electrochemistry ,Copper ,Solvent ,chemistry.chemical_compound ,chemistry ,Oxidation state ,Pyridine ,Polymer chemistry ,Solvent effects ,Corrole - Abstract
Two meso-phenyl chloro-substituted copper corroles were synthesized and characterized by a variety of spectroscopic techniques. The investigated compounds are represented as ((ClPh)3Cor)Cu and ((Cl2Ph)3Cor)Cu , where (ClPh)3Cor and (Cl2Ph)3Cor are the trianions of the 5,10,15-tri- (4-chlorophenyl)corrole and 5,10,15-tri(2,4-dichlorophenyl)corrole, respectively. UV-visible and ESR spectroscopy revealed that the electronic ground state of each copper corrole is solvent dependent. Both compounds contain Cu(III) corroles in the solid state and in solutions of CH2Cl2 , but an equilibrium exists between Cu(III) and its Cu(II) form in pyridine, DMSO or DMF. The Cu(II) corrole could also be generated by controlled potential reduction in a thin-layer cell, which is reversible in CH2Cl2 or DMF containing 0.1 M TBAP. The structure of ((ClPh)3Cor)Cu was determined by a single-crystal X-ray study.
- Published
- 2011
29. Reductive dechlorination of DDT electrocatalyzed by synthetic cobalt porphyrins in N,N′-dimethylformamide
- Author
-
Weihua Zhu, Yuanyuan Fang, Zhongping Ou, Wei Shen, Ying Zhang, Guifen Lu, and Karl M. Kadish
- Subjects
Inorganic chemistry ,chemistry.chemical_element ,General Chemistry ,Porphyrin ,Medicinal chemistry ,Catalysis ,Perchlorate ,chemistry.chemical_compound ,chemistry ,Oxidation state ,Tetraphenylporphyrin ,Reductive dechlorination ,Cyclic voltammetry ,Cobalt - Abstract
Two cobalt porphyrins, (OEP) CoII and (TPP) CoII , where OEP and TPP are the dianions of octaethylporphyrin and tetraphenylporphyrin, respectively, were examined as electrocatalysts for the reductive dechlorination of DDT (1,1-bis(4-chlorophenyl)-2,2,2-trichloroethane) in N,N′-dimethylformamide (DMF) containing 0.1 M tetra-n-butylammonium perchlorate (TBAP). No reaction is observed between DDT and the porphyrin in its Co(II) oxidation state but this is not the case for the reduced Co(I) forms of the porphyrins which electrocatalyze the dechlorination of DDT, giving initially DDD (1,1-bis(4-chlorophenyl)-2,2-dichloroethane), DDE (1,1-bis(4-chlorophenyl)-2, 2-dichloroethylene) and DDMU (1,1-bis(4-chlorophenyl)-2-chloroethylene) as determined by GC-MS analysis of the reaction products. A further dechlorination product, DDOH (2,2-bis(4-chlorophenyl)ethanol), is also formed on longer timescales when using (TPP)Co as the electroreduction catalyst. The effect of porphyrin structure and reaction time on the dechlorination products was examined by GC-MS, cyclic voltammetry, controlled potential electrolysis and UV-visible spectroelectrochemistry and a mechanism for the reductive dechlorination is proposed.
- Published
- 2011
Catalog
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