Mixed Valency in Hydrogen Bonded ‘Dimers of Dimers’

Dimolybdenum quadruply bonded compounds containing a
pendant lactam
functional group form self-complementary hydrogen bonded ‘dimers
of dimers’ in the solid-state and CH2Cl2 solutions. Electrochemical studies in CH2Cl2 show two consecutive one-electron redox processes corresponding
to oxidation of the Mo24+ cores. Spectroelectrochemical
studies on the ‘dimers of dimers’ show no evidence of
intervalence charge transfer bands in the mixed valence radical cations
formed by one-electron oxidation, indicating that they are examples
of proton-coupled mixed valency.