Preparation of silicas combined with optically active organic compounds: optical resolution of metal chelate complexes on the silica composites

A new type of optically active organic-inorganic composite was prepared by a sol-gel method in which tetraethoxysilane is hydrolysed after replacing the ethoxy group withd-lactose orl-tartaric acid, and compared in the optical resolution of tris(2,4-pentanedionato)metal complexes with conventional silica composites (kneading withl-lactose and impregnation with anl-lactose orl-tartaric acid solution) and the organic compounds themselves. The sol-gel composites showed much higher optical resolution abilities than the conventional materials and, in addition the optically active organic compounds could not resolve the racemate under similar conditions. The high resolution ability of the sol-gel composites was deduced to come from the combined effect of silica and a dispersed optically active organic compound.