Reactions of [η 5-carboxycyclopentadiene][η 4-tetraphenylcyclo butadiene] cobalt with alkyl and aryl tin oxides: Synthesis, structural studies and electrochemistry of novel monomeric and dimeric [η 5-carboxycyclopentadiene][η 4-tetraphenylcyclobutadiene]cobalt based stannoxanes

Abstract

Reactions of [η 5-carboxycyclopentadienyl][η 4-tetraphenylcyclobutadiene] cobalt, Ph 4C 4CoC 5H 4COOH ( 1), with (Ph 3Sn) 2O, [( n-Bu) 2SnO] n and (Ph 2SnO) n in refluxing toluene resulted in the formation of the monomeric compound Ph 3SnOC(O)C 5H 4CoC 4Ph 4 ( 2) and dimeric compounds n-Bu 2Sn[OC(O)C 5H 4CoC 4Ph 4] 2 ( 3) and Ph 2Sn[OC(O)C 5H 4CoC 4Ph 4] 2 ( 4), respectively. Reactions carried out in the solid state by mechanical grinding also yielded same results. Crystal structure determination and cyclic voltammetric studies of compounds 1, 2, 3 and 4 have been carried out and compared with similar ferrocene carboxylic acid derivatives. The structures and electrochemistry of these compounds are compared with analogous organotin ferrocene carboxylates. The results obtained from the reaction of 1 with alkyl and aryl tin oxides suggest that the formation of stannoxanes assemblies having more than two carboxylate units are not favored indicating that 1 is a highly sterically hindered metallocene carboxylic acid.