Preparation of surface molecularly imprinted Ru-complex catalysts for asymmetric transfer hydrogenation in water media

Molecularly imprinted Ru-complex catalysts acting in water were prepared on a SiO2 surface by molecular imprinting of a SiO2-supported Ru-complex using organic polymers as surface matrix overlayers. (R)-1-(o-fluorophenyl) ethanol, which is one of the hydrogenated products of o-fluoroacetophenone, was imprinted on the supported Ru-complex as a template, and an active Ru-complex with a shape-selective reaction space (molecularly imprinted cavity) was prepared inside the wall of the hydrophobic organic polymer matrix overlayers. Structures of the SiO2-supported and molecularly imprinted Ru catalysts were characterized by means of solid-state NMR, XPS, XRF, ICP, UV/vis, XAFS, TGA, and SEM. The molecularly imprinted Ru catalysts exhibited fine shape selectivity and enantioselectivity for the asymmetric transfer hydrogenation of o-fluoroacetophenone and its derivatives.