INFLUENCE OF STERIC BULK ON THE RELATIVE STABILITY AND INTERCHANGEABILITY OF THE VARIOUS OXIDATION-STATES FOR NICKEL COMPLEXED WITH 1,2-BIS(DIALKYLPHOSPHINO)BENZENE

The reduction potentials and electrochemical reversibilities of a series of nickel complexes of 1, 2-bis(dialkylphosphino)benzene are sensitive to the steric bulk of the alkyl substituents. With very large ligands, electroreduction is accompanied by rapid secondary chemical reaction, and spectroscopic evidence for the intermediacy of a coordinatively unsaturated species is presented. The potentials required for electrooxidation of these complexes are shifted to more positive potentials by increasing bulk of the alkyl substituents on the bisphosphino ligands. © 1992, Taylor & Francis Group, LLC. All rights reserved.