Electrochemical and in situ spectroelectrochemical behavior of 2,3,7,8,12,13,17,18-octakis(hexyl-thio) tetraazaporphyrin (H2OHTTAP) and [Zn(II)OHTTAP]

2001 ◽  
Vol 05 (06) ◽  
pp. 523-527 ◽  
Author(s):  
YANXIU ZHOU ◽  
ZHENXING WANG ◽  
DAIKE WANG ◽  
KENICHI SUGIURA ◽  
YOSHITERU SAKATA
Keyword(s):  
Electron Transfer ◽  
Differential Pulse ◽  
Single Electron ◽  
Single Electron Transfer ◽  
Free Base ◽  
Cation Radicals ◽  
Pulse Voltammetry ◽  
Electron Reduction

The characterization of free base porphyrin 2,3,7,8,12,13,17,18-octakis(hexyl-thio) tetraazaporphyrin (H2OHTTAP) and its zinc(II) complexes [ Zn (II)OHTTAP] containing eight thioether groups at the β-pyrrole positions of the macrocycle was reported. Results obtained by cyclic voltammetry and differential pulse voltammetry indicated a five-electron reduction in five steps for each complex. They were oxidized in two single-electron-transfer steps to yield π-cation radicals and dications and reduced in three single-electron-transfer steps to yield π-anion radicals, dianions and trianions, respectively. The redox property of H2OHTTAP was unusual as compared to porphyrins (PPs) and phthalocyanines (Pcs). Each process was monitored by in situ thin-layer spectroelectrochemistry, which indicated that only the ligand was electroactive. The existence of the eight hexylthio groups was responsible for the intrastack interactions and enhanced intracolumnar and intercolumnar electron motions, resulting in improved conductivity.

Effect of alkyl group length on the conductivity in the 2,3,7,8,12,13,17,18-octakis(alkyl-thio)tetraazaporphyrins and redox properties of the metallooctakis(hexyl-thio)tetraazaporphyrins

2002 ◽  
Vol 06 (07) ◽  
pp. 447-455
Author(s):  
Bin Yu ◽  
Yanxiu Zhou ◽  
Daike Wang ◽  
Zhenxing Wang ◽  
Kenichi Sugiura ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Cation Radical ◽  
Differential Pulse ◽  
Single Electron ◽  
Central Metal Atom ◽  
Central Metal ◽  
Single Electron Transfer ◽  
Electron Transfer Pathways ◽  
Chain Lengths

A series of 2,3,7,8,12,13,17,18-octakis(alkyl-thio)tetraazaporphyrins (H2OATTAP) with different alkyl chain lengths have been synthesized. Cyclic voltammetry and differential pulse voltammetry have been used to investigate the effect of the controlled lengths of the eight peripheral thioether tails on the redox behavior of the molecules. The electrochemical reduction of octakis(hexyl-thio)tetraazaporphyrins, MOHTTAP (where M = Cu , Ni ), was studied in 1,2-dichloroethane at a platinum electrode. The Cu derivative was oxidized in one single-electron-transfer step to yield a π-cation radical and reduced in three single-electron-transfer steps to yield a π-anion radical, dianion and trianion, respectively. For the Ni derivative, electron transfer reactions involving both the central metal atom and the macrocyclic ring were observed. Electron transfer pathways are proposed based upon voltammetric and in situ spectroelectrochemical results.

scholarly journals Computational Characterization of Single-Electron Transfer Steps in Water Oxidation

Inorganics ◽  
2019 ◽  
Vol 7 (3) ◽  
pp. 32 ◽  
Author(s):  
Adiran de Aguirre ◽  
Ignacio Funes-Ardoiz ◽  
Feliu Maseras
Keyword(s):  
Electron Transfer ◽  
Water Oxidation ◽  
Density Functional ◽  
Outer Sphere ◽  
Oxidation Catalysis ◽  
Single Electron ◽  
Single Electron Transfer ◽  
Inner Sphere ◽  
Water Oxidation Catalysis

The presence of single-electron transfer (SET) steps in water oxidation processes catalyzed by first-row transition metal complexes has been recently recognized, but the computational characterization of this type of process is not trivial. We report a systematic theoretical study based on density functional theory (DFT) calculations on the reactivity of a specific copper complex active in water oxidation that reacts through two consecutive single-electron transfers. Both inner-sphere (through transition state location) and outer-sphere (through Marcus theory) mechanisms are analyzed. The first electron transfer is found to operate through outer-sphere, and the second one through inner-sphere. The current work proposes a scheme for the systematic study of single-electron transfer in water oxidation catalysis and beyond.

Electrochemical and in situ spectroelectrochemical investigations into the redox and aggregation behaviours of phthalocyanines bearing octyl 4-phenyloxyacetate moieties

2010 ◽  
Vol 88 (4) ◽  
pp. 375-382 ◽  
Author(s):  
İmran Koç ◽  
Meryem Çamur ◽  
Mustafa Bulut ◽  
A. Riza Özkaya
Keyword(s):  
Cobalt Complex ◽  
Differential Pulse ◽  
Redox Processes ◽  
Tetrabutylammonium Perchlorate ◽  
Pulse Voltammetry ◽  
The Difference ◽  
Electron Reduction ◽  
Aggregation Phenomenon ◽  
Aggregation Phenomena

Electrochemical and spectroelectrochemical properties of phthalocyanines (H2Pc, ZnPc, NiPc, CuPc, and CoPc) involving octyl 4-phenyloxyacetate moieties have been investigated by cyclic voltammetry and differential pulse voltammetry on Pt in dimethylsulfoxide – tetrabutylammonium perchlorate. These measurements showed that the complexes undergo subsequent one-electron reduction and oxidation processes. In situ UV–vis spectroelectrochemical measurements enabled us to identify the ligand- and metal-based redox processes, and evaluate the effect of aggregation phenomena on these processes. The cobalt complex showed both metal-based and ring-based one-electron redox processes, while the other complexes displayed only ring-based one-electron couples. It was observed that the redox processes of H2Pc, NiPc, and CuPc are coupled by aggregation phenomenon, whereas those of ZnPc and especially CoPc are not, probably owing to the difference in their axial coordinating properties.

The electron that breaks the catalyst’s back – excited state dynamics in intermediates of molecular photocatalysts

2021 ◽  
Author(s):  
Carolin Müller ◽  
Ilse Friedländer ◽  
Benedikt Bagemihl ◽  
Sven Rau ◽  
Benjamin Dietzek
Keyword(s):  
Electron Transfer ◽  
Excited State ◽  
Single Electron ◽  
Intramolecular Electron Transfer ◽  
Excited State Dynamics ◽  
Transfer Processes ◽  
Electron Reduction ◽  
Electron Transfer Processes ◽  
Franck Condon

In situ spectroelectrochemical studies focussing on the Franck-Condon region and sub-ns electron transfer processes in Ru(II)-tpphz-Pt(II) based photocatalysts reveal that single-electron reduction effectively hinders intramolecular electron transfer between the photoexcited...

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