Immobilization of a Quinonoid Rhodium Catalyst on Silica Gel by the Surface Sol−Gel Process and Catalytic Activity for Phenylacetylene Polymerization

A metal alkoxide monolayer was formed on the surface of silica gel by the SSG process (surface sol−gel). Quinonoid rhodium complexes possessing an acidic −OH group were immobilized on the alkoxide layer by deprotonation and subsequent formation of strong M−O (quinonoid) bonds (M = Ti, Zr). The silica-gel-supported rhodium catalyst shows a high reactivity for the stereospecific polymerization of phenylacetylene to cis-transoidal polyphenylacetylene.