Studies on electron transfer reactions of Keggin-type mixed addenda heteropolytungstovanadophosphates with NADH

Journal of Chemical Sciences

Kasi Rajasekaran1¹  Ponnusamy Sami¹ 

[1] Post Graduate Department of Chemistry, Virudhunagar Hindu Nadars’ Senthikumara Nadar College, Virudhunagar 626 001$$

关键词: Nicotinamide adenine dinucleotide (NADH);    heteropoly-tungstovanadophosphate;    outer sphere electron transfer reactions.;   

DOI  :  

来源: Indian Academy of Sciences

【 摘 要 】

The coenzyme nicotinamide adenine dinucleotide (NADH) undergoes facile electron transfer reaction with vanadium (V) substituted Keggin-type heteropolyanions (HPA) [PVVW11O40]4- (PV1) and [PV$^{V}_{2}$W10O40]5- (PV2) in aqueous phosphate buffer of pH 6 at ambient temperature. Electrochemical and optical studies show that the stoichiometry of the reaction is 1 : 2 (NADH : HPA). EPR and optical studies show that HPA act as one electron acceptor and the products of electron transfer reactions are one electron reduced heteropoly blues (HPB), viz. [PVIVW11O40]5- and [PVIVVVW10O40]6-. Oxygraph measurements show that there is no uptake of molecular oxygen during the course of reaction. The reaction proceeds through multi-step electron-proton-electron transfer mechanism, with rate limiting initial one electron transfer from NADH to HPA by outer sphere electron transfer process. Bimolecular rate constant for electron transfer reaction between NADH and PV2 in phosphate buffer of pH = 6 has been determined spectrophotometrically.

【 授权许可】

Unknown