Mesoporous SBA-15: A Superior Heterogeneous Catalytic Support for Multicomponent Organic Synthesis

The design and synthesis of various porous solids have been gaining much attention in recent years owing to their diverse chemistry and widespread application potential in various fields. In particular, the synthesis and functionalization of highly ordered, uniform mesoporous silica based material such as SBA-15 are attaining extensive popularity among researchers due to their fascinating properties. It exhibits very high surface area, high thermal and hydrothermal stability and more importantly it possesses two dimensional hexagonally ordered cylindrical mesochannels that can be used as nano reactors for embedding catalytic species such as nanoparticles, complexes and heteropoly acids etc. The encapsulation/immobilization of these catalytically active species onto SBA-15 can be achieved through functionalization of the surface with various functional groups which creates anchors for capturing these species. The resulting encapsulated materials act as superior catalytic system for various important multicomponent reactions (MCRs). This MCRs approach is an integral part of numerous research efforts involved in the drug development programs to get synthetic targets in expeditious way. Some of the targeted compounds such as dihydropyrimidinones, propargylamines, spiroindolines, β-amino carbonyl compounds etc. have shown their biological activities as drug molecules. Recently, various composite materials of SBA-15 were successfully employed as heterogeneous catalysts for these types of reactions. Reusability and selectivity are the certain advantages of this present catalytic system that makes it superior to the other catalytic system available in the literature. A discussion along with examples of application of SBA-15 composites for MCRs will be described in this chapter.

Keywords: Biological activities, Catalysts, Encapsulation, Heteropoly acids, Hexagonal, Hydrothermal, Immobilization, Ion exchange, Mechanism, Mesoporous, Metal complexes, Multicomponent reactions, Nanoparticles, Organicspecies, Polymers, Self-assemble, Sensing, Silicate, Solid acids, Solid bases, Sol-gel, Sorption, Surface functionalization, Synergistic effects, SBA-15, Template.