Immobilization of a N-substituted azaphosphatrane in nanopores of SBA-15 silica for the production of cyclic carbonates

Abstract

A novel N-substituted azaphosphatrane molecular precursor bearing an alkyne tether was synthesized using a multi-step strategy and covalently immobilized onto SBA-15 type silica through triazole linkages by means of the well-known click chemistry. The resulting hybrid material, [7]@SBA-15, was characterized well by methods appropriate to molecular species (e.g. solid state ¹³C, ³¹P and ²⁹Si NMR, infrared spectroscopy and elemental analysis) as well as techniques more commonly associated with the characterization of mesoporous solids (nitrogen sorption isotherms, powder X-ray diffraction, TGA analysis). The catalytic activity of [7]@SBA-15 was then evaluated in the coupling of CO₂ with two epoxides (styrene oxide and epichlorohydrin) and compared to its monotriazole modified AZAP molecular analog, 8. This work represents the first example of silica modified N-substituted azaphosphatrane for the production of cyclic carbonates.