4- and 3-Hydroxypyridine complexes of pentacyanoferrate(II, III)

Chen, Chang-nan; Wu, Ming-chu; Yeh, Andrew; Tsai, T. Y. R.

doi:10.1016/s0020-1693(97)05557-6

Cited by 15 publications

(3 citation statements)

References 24 publications

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“…This can be attributed to the amine being protonated at pH=7 (pK a = 9.12) therefore resulting in a strong electron-withdrawing ammonium group 37. The absence of catalytic activity observed with 4-hydroxypyridine derivative ( 7 ), may be due to the formation of a 4-pyridone tautomer 38. The above results are in agreement with literature data reported by us18 and by Reisner and coworkers 39.…”

Section: Resultssupporting

confidence: 89%

“…37 The absence of catalytic activity observed with 4-hydroxypyridine derivative (7), may be due to the formation of a 4-pyridone tautomer. 38 The above results are in agreement with literature data reported by us 18 and by Reisner and coworkers. 39 Both studies indeed demonstrated enhanced electrochemical H 2 evolution activity for cobaloximes with electron-enriched axial ligands.…”

Section: It Appearssupporting

confidence: 93%

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Photochemical hydrogen production and cobaloximes: the influence of the cobalt axial N-ligand on the system stability

et al. 2016

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We report on the first systematic study of cobaloxime-based hydrogen photoproduction in mixed pH 7 aqueous/acetonitrile solutions and demonstrate that H2 evolution can be tuned through electronic modifications of the axial cobalt ligand or through introduction of TiO2 nanoparticles. The photocatalytic systems consist of various cobaloxime catalysts [Co(dmgH)2(L)Cl] (L = nitrogen-based axial ligands) and a water soluble porphyrin photosensitizer. They were assayed in the presence of triethanolamine as a sacrificial electron donor. Optimal turnover numbers related to the photosensitizer are obtained with electron-rich axial ligands such as imidazole derivatives (1131 TONs with N-methyl imidazole). Lower stabilities are observed with various pyridine axial ligands (443 TONs for para-methylpyridine), especially for those containing electron-acceptor substituents. Interestingly, when L is para-carboxylatopyridine the activity of the system is increased from 40 to 223 TONs in the presence of TiO2 nanoparticles.

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Section: Resultssupporting

confidence: 89%

Section: It Appearssupporting

confidence: 93%

Photochemical hydrogen production and cobaloximes: the influence of the cobalt axial N-ligand on the system stability

et al. 2016

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“…27 A similarly small catalytic influence was observed when adding 4-hydroxypyridine, which may be due to the formation of a 4-pyridone tautomer. 45 An imidazole substituted catalyst showed high catalytic currents (Fig. S6, ESI †), but the electron-rich cobaloxime makes reduction of Co II more difficult, 35 consequently producing a less attractive catalytic overpotential for this species.…”

Section: Table 1 Summary Of Emocs Data From Pyridine-substituted Coba...mentioning

confidence: 99%

Development and understanding of cobaloxime activity through electrochemical molecular catalyst screening

Wakerley

Reisner

2014

Phys. Chem. Chem. Phys.

123

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Electrochemical molecular catalyst screening (EMoCS) has been developed. This technique allows fast analysis and identification of homogeneous catalytic species through tandem catalyst assembly and electrochemistry. EMoCS has been used to study molecular proton reduction catalysts made from earth abundant materials to improve their viability for water splitting systems. The efficacy of EMoCS is proven through investigation of cobaloxime proton reduction activity with respect to the axial ligand in aqueous solution. Over 20 axial ligands were analysed, allowing rapid identification of the most active catalysts. Structure-activity relationships showed that more electron donating pyridine ligands result in enhanced catalytic currents due to the formation of a more basic Co-H species. The EMoCS results were validated by isolating and assaying the most electroactive cobaloximes identified during screening. The most active catalyst, [Co(III)Cl(dimethyl glyoximato)2(4-methoxypyridine)], showed high electro- and photoactivity in both anaerobic and aerobic conditions in pH neutral aqueous solution.

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Kinetic studies on the reaction of sodium hexa‐cyanoferrate(II) complex with peroxydisulfate anion

et al. 2004

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The oxidation of Nde(CN)6 complex by S,Oi-anion was found to follow an outer-sphere electron transfer mechanism. We fmtly canied out the reaction at pH= 1. The specific rate constants of the reaction, bx, are (8.1 C 0.07)X10-2 and (4.3~0.1)XIO-* mol-'-L*s-' at p=1.0 rnol*L-' NaC104, T=298 K for pH=l (0.1 mol*L-' HC104) and 8, respectively. The activation parameters, obtained by measuring the rate constants of oxidation The first and the third steps are diffusion-controlled reactions, and Eq. (3) is often the rate determining step. If one of the reactants is in excess (usually oxidant) and the reaction proceeds to completion, this mechanism leads to the rate law given byDue to the instability of N-aromatic hetercyclic complexes in acidic solutions,' previous studies on the oxidation of Fe(CN), L3-complexes were never carried out in a solution at p H 6 4 . For this reason we would like to extend our study to the oxidation of Fe(CN):-complex in an acidic medium because the complex is rather stable in the acid solution. In this paper we report the results of our kinetic study on the oxidation of Fe(CN):-complex in 0.1 mol-L-' HC104 solution. For the purpose of comparison, the oxidation of Fe(CN):-at pH=8 was also carried out.

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4- and 3-Hydroxypyridine complexes of pentacyanoferrate(II, III)

Cited by 15 publications

References 24 publications

Photochemical hydrogen production and cobaloximes: the influence of the cobalt axial N-ligand on the system stability

Photochemical hydrogen production and cobaloximes: the influence of the cobalt axial N-ligand on the system stability

Development and understanding of cobaloxime activity through electrochemical molecular catalyst screening

Kinetic studies on the reaction of sodium hexa‐cyanoferrate(II) complex with peroxydisulfate anion

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