Ligand rotamers and redox isomerism: metallo-pseudo-prolines

Abstract

A ligand rotation which orientates the oxygen atom of an amide group towards or away from a neighbouring metal centre provides rotamers A and B with E° potentials which differ by 150 mV; oxidation of the metal centre of B switches the system from a state in which there is a small difference in the relative populations of the rotamers to one in which the cis-amide conformation greatly predominates; this new metallocycle system can be viewed as a pseudo-proline with redox sensitive rotameric properties.