Urea and Thiourea-Functionalized Mesoporous Silica Nanoparticle Catalysts with Enhanced Catalytic Activity for Diels-Alder Reaction

A series of urea- and thiourea-functionalized mesoporous silica nanoparticles (MSN) was synthesized. These materials exhibited a superior catalytic reactivity for Diels-Alder reaction than their homogeneous analogues. The reactivity enhancement was attributed to the site isolation effect induced by the heterogenization of individual catalytic group. The surface hydrogen bonding between the organic catalysts and silanols also improved the catalytic reactivity.