Chapter 11 - Organically Modified Ordered Mesoporous Siliceous Solids

Abstract

This chapter gives an overview of the main advances in the development of ordered mesoporous siliceous solids functionalized by organic groups including periodic organo-silica mesoporous materials. The growing interest in such organic modifications can be attributed to the characteristics of ordered mesoporous silica (OMS) materials. Moreover, the amorphous character of their frameworks offers a large number of available silanol groups that can easily react with various functional groups and allows the strong and stable coupling of organic moieties to the silica network. An important attention has been also given to the shape modeling of these hybrid materials with a particular effort on the elaboration of thin films and monoliths. Three routes are commonly followed to organically modify OMS materials. Organic pendant groups can be anchored to the silica backbone by post-synthesis reactions with residual Si–OH groups (post-syntheis grafting) or by a direct synthesis process based on co-condensation of silica precursors with organoalkoxysilanes. Organically modified OMS prepared by post-synthesis or by direct synthesis have been compared in terms of structural and textural characteristics, organic group loadings, localization, and accessibility. Catalysis has been the most studied application for the organically modified mesoporous siliceous solids. Porous materials are commonly employed for the adsorption of molecules or elements and can be found in everyday applications. The large potential of these materials in terms of structural and textural characteristics, surface and bulk properties, processing, functionalities, and so on make them suitable materials for a large panel of applications.