Reactions in Solid and Constrained State, IV.~(1a-c)) Preparation and Solid-State Photoracemization of Optically Active Alkyl Cobaloxime Complexes

摘要

Various optically active 1-substituted and 1,2-disubstituted ethyl cobaloxime [bis(dimethylglyoximato) cobalt(III)] complexes including deuterium-labeled complexes were prepared. Their photoracemization was found to occur upon irradiation of visible light in the solid-state. The reaction rate was much greater than that of solid-state recemization by irradiation of X-rays. The rats were not controlled by the electronic character of axial base and alkyl group but by the crystal lattice: the volume and shape of the reaction cavity, flexibility of the cavity, and intermolecular interaction such as hydrogen bonding. The experiments using deuterium-labeled complexes revealed the main reaction path in which the racemization proceeds mainly through out-of-plane rotation of the alkyl radical.