The reduced form of the nicotinamide-adenine dinucleotide coenzyme(NAD(P)H)plays an important role in many bio-reductions by transferring a hydride ion or an electronto the surrounding substrate(see eq.(1),R represent...The reduced form of the nicotinamide-adenine dinucleotide coenzyme(NAD(P)H)plays an important role in many bio-reductions by transferring a hydride ion or an electronto the surrounding substrate(see eq.(1),R represents adenine dinucleotide).展开更多
1 Introduction Much research work has been done on the mechanism of photo-induced reduction of quinone dyes by electron donors with visible light. Two ways to obtain the net two-electron reduction product QH^- bave be...1 Introduction Much research work has been done on the mechanism of photo-induced reduction of quinone dyes by electron donors with visible light. Two ways to obtain the net two-electron reduction product QH^- bave been proposed. One is the direct two-electron transfer (electron-proton-electron transfer) within the complex and the other is the disproportionatioh of the semiquinone radical QH·formed by one-electron transfer.展开更多
The reaction between chloranil and N-benzyldihydronicotinamide(BNAH)in borate buffer/DMF was investigated.The reaction mixture gave a strong esr signal,which is consistent with that of chloranil anion radical,and tetr...The reaction between chloranil and N-benzyldihydronicotinamide(BNAH)in borate buffer/DMF was investigated.The reaction mixture gave a strong esr signal,which is consistent with that of chloranil anion radical,and tetrachlorohydrophenol(QH_2)and N-benzylnicotinamide (BNA^+)were obtained as the sole products.When the reaction was run in benzene solution,a green coloured charge-transfer complex between the reactants could be isolated,which decomposed in polar solvents to give BNA-+ and QH_2.Based on kinetic studies by esr spectroscopy by the stopped-flow technique,a two-step electron-transfer mechanism for the reactionis proposed in contrast to the hydride-transfer mechanism reported in the literature.展开更多
文摘The reduced form of the nicotinamide-adenine dinucleotide coenzyme(NAD(P)H)plays an important role in many bio-reductions by transferring a hydride ion or an electronto the surrounding substrate(see eq.(1),R represents adenine dinucleotide).
基金Project supported by the National Natural Science Foundation of China
文摘1 Introduction Much research work has been done on the mechanism of photo-induced reduction of quinone dyes by electron donors with visible light. Two ways to obtain the net two-electron reduction product QH^- bave been proposed. One is the direct two-electron transfer (electron-proton-electron transfer) within the complex and the other is the disproportionatioh of the semiquinone radical QH·formed by one-electron transfer.
文摘The reaction between chloranil and N-benzyldihydronicotinamide(BNAH)in borate buffer/DMF was investigated.The reaction mixture gave a strong esr signal,which is consistent with that of chloranil anion radical,and tetrachlorohydrophenol(QH_2)and N-benzylnicotinamide (BNA^+)were obtained as the sole products.When the reaction was run in benzene solution,a green coloured charge-transfer complex between the reactants could be isolated,which decomposed in polar solvents to give BNA-+ and QH_2.Based on kinetic studies by esr spectroscopy by the stopped-flow technique,a two-step electron-transfer mechanism for the reactionis proposed in contrast to the hydride-transfer mechanism reported in the literature.
