Studies on the Reactions of Dihydrogen with Salts of Platinum Carbonyl Cluster Anions (Chini Clusters) and Redox Active Countercations

摘要

Reactions of A_n[Pt_(12)(CO)_(24)] (A=methylene blue (MB~+),safranine O (Saf~+),nicotinamide benzyl chloride (BNA~+),n=2;A=methylviologen (MV~(2+)),n=1) with dihydrogen in DMF and DMSO have been studied.Spectroscopic (NMR,ESR,and UV-vis) monitoring shows selective and total reduction of MB~+,Saf~+,and MV~(2+) to MBH,SafH,and MV~+ respectively,accompanied by conversion of [Pt_(12)(CO)_(24)]~(2-) to [Pt_9(CO)_(18)]~(2-).No BNAH (analogue and model for NADH) is formed in the reaction of [BNA]_2[Pt_(12)(CO)_(24)] with dihydrogen.However,in the reactions of BNA~+C1~-,[Saf]_2[Pt_(12)(CO)_(24)],and dihydrogen,BNAH is formed in small quantities in DMSO and quantitatively in a biphasic system (water and dichloromethane).The redox behaviors of MB~+,Saf~+,MV~(2+),and BNA~+ as chloride salts have also been studied in DMF by cyclic voltammetry,and the data have been used to rationalize some of the observed reactions.The dihydrogen-driven,[Bu_4N]_2[Pt_(12)(CO)_(24)]-catalyzed transport of A~+ (A~+=MB~+,Saf~+) as AH through a liquid membrane has also been studied.