Periodic Mesoporous Organosilicas: from simple to complex bridges; a comprehensive overview of functions, morphologies and applications

Abstract

Periodic Mesoporous Organosilicas (PMOs) were developed in 1999 and are basically ordered templated mesoporous organosilicas, prepared by the combination of a surfactant as template and a silsesquioxane as the organosilica precursor. They were one of the first examples of the so-called "hybrid" organic/inorganic materials. In the years that followed, an amazing variety of functional groups, morphologies and applications has been developed. Some of these high-end applications, like low-k buffer layers in microelectronics, chiral catalysts, chromatographic supports, selective adsorbents and light-harvesting devices, have clearly shown their potential. In this review, we will give a comprehensive overview of all these different functionalities and applications that have been created for Periodic Mesoporous Organosilicas.

Periodic mesoporous organosilicas for advanced applications

“…[6][7][8]10,13,14 For example, Inagaki and co-workers 14 produced a PMO material that contains benzene groups in the pore wall framework and the phenylsulfonic acid functionalities (C 6 H 5 -SO 3 H) that face toward the mesopore channels. The sulfonic acid functional groups were derived from the mercaptopropyl groups (-C 3 H 6 SH) by oxidative transformation of surface thiol groups into sulfonic acid groups.…”

“…20 More advanced PMO materials are those with bridges containing hetero atoms such as nitrogen or sulfur. 13,15,21 Long and flexible functionalities are difficult to incorporate into PMOs. In these cases, tetraethyl orthosilicate (TEOS) or tetramethyl orthosilicate (TMOS) are added to assist in the formation of more rigid and ordered mesophases.…”

“…Organosilica precursors with linear bridges containing nitrogen and sulfur atoms were synthesized to produce azobenzene units, diimine Schiff base units, diimine/diacetylenic units, amine units and sulfide units. 13,15 The sulfide moieties in PMOs are of interest for their high selectivity in adsorbing contaminants. Moreover, these groups can be a source of possible acid functionalities through a postoxidation treatment to provide sulfonic acid moieties.…”

“…13 These ionic bridged organosilica precursors can lead to advanced materials for heterogeneous catalysis, adsorption and photochemical processes. 13 (EtO) 3 Si Si(OEt) 3 (EtO) 3 PMO materials with chiral centers have also attracted our interest for their potential in high-technology applications, such as chiral chromatography, chiral separation and asymmetric catalysis.…”

“…Later, Fröba and co-workers, 8 Jaroniec, 9 Inagaki and co-workers, 6 Fujita and Inagaki, 7 Lin and co-workers, 10 Ozin and co-workers 11 and Corma and co-workers 12 published some excellent reviews of PMO studies. The most recent review paper was by Van Der Voort and co-workers, 13 who provided a comprehensive overview of these materials, discussing their functionalities, morphology and applications by referring to approximately 300 works on PMO materials.…”