Periodic mesoporous organosilica incorporating a catalytically active vanadyl Schiff base complex in the framework

A vanadyl Schiff base complex having two terminal trimethoxysilyl groups peripheral to the ligand has been used to obtain a MCM-41-like mesoporous organosilicate that has been found to catalyze efficiently the cyanosilylation of carbonyl groups. Evidence for the successful preparation of the periodic mesoporous organosilica is based on powder XRD (high periodicity), isothermal Ar adsorption (900 m(2)/g), mono-modal pore-size distribution (42 Angstrom), diffuse reflectance UV-visible spectroscopy (characteristic absorption band of vanadyl salen complex), and Si-29 NMR (presence of T-3 silicon atoms, CH2-Si(OSidrop)(3)). In addition, we have been able to prepare a chiral vanadyl salen complex that is able to catalyze the carbonyl addition with 30% ee. (C) 2004 Elsevier Inc. All rights reserved.