Periodic mesoporous organosilicas (PMOs) prepared by surfactant-directed polycondensation of bridged organosilane precursors are promising for a variety of next-generation functional materials, because their large surface areas, well-defined nanoporous structures and the structural diversity of organosilica frameworks are advantageous for functionalization. This critical review highlights the unique structural features of PMOs and their expanding potential applications. Since the early reports of PMOs in 1999, various synthetic approaches, including the selection of hydrolytic reaction conditions, development of new precursor compounds, design of templates and the use of co-condensation or grafting techniques, have enabled the hierarchical structural control of PMOs from molecular- and meso-scale structures to macroscopic morphology. The introduction of functional organic units, such as highly fluorescent π-conjugates and electroactive species, into the PMO framework has opened a new path for the development of fluorescent systems, sensors, charge-transporting materials and solid-state catalysts. Moreover, a combinational materials design approach to the organosilica frameworks, pore wall surfaces and internal parts of mesopores has led to novel luminescent and photocatalytic systems. Their advanced functions have been realized by energy and electron transfer from framework organics to guest molecules or catalytic centers. PMOs, in which the precise design of hierarchical structures and construction of multi-component systems are practicable, have a significant future in a new field of functional materials (93 references).

Syntheses, properties and applications of periodic mesoporous organosilicas prepared from bridged organosilane precursors.

Metal–organic frameworks as catalysts: the role of metal active sites

A topical review of the use of non-porous and porous inorganic materials as supports for the immobilization of ILs and their catalytic applications is given. The basic principles and the supports that are being used in various concepts emerging from supported ionic liquids (SILs) including supported ionic liquid films (SILFs), supported ionic liquid catalysis/catalysts (SILC/SILCAs), solid catalysts with ILs (SCILs), solid catalysts with IL layer (SCILL), supported IL nanoparticles (SILnPs) and supported ionic liquid phase (SILP) catalysts (SILPC) are first discussed. In addition, we provide a comprehensive review of the SILs concept dealing with inorganic supports, such as layered silicates, porous glass, zeolites, mesoporous (MCM) and PMO (periodic mesoporous organosilica) materials; and their applications.

https://www.tpbin.com/Uploads/Subjects/6bac8b60-e73d-4b66-aa2d-b8345e2004aa.pdf

Supported ionic liquids on non-porous and porous inorganic materials—A topical review

Current Opinion in Colloid & Interface Science

Recently, organic-inorganic hybrid materials have attracted tremendous attention thanks to their outstanding properties, their efficiency, versatility and their promising applications in a broad range of areas at the interface of chemistry and biology. This article deals with a new family of surface-reactive organic-inorganic hybrid materials built from chitosan microspheres. The gelation of chitosan (a renewable amino carbohydrate obtained by deacetylation of chitin) by pH inversion affords highly dispersed fibrillar networks shaped as self-standing microspheres. Nanocasting of sol-gel processable monomeric alkoxides inside these natural hydrocolloids and their subsequent CO(2) supercritical drying provide high-surface-area organic-inorganic hybrid materials. Examples including chitosan-SiO(2), chitosan-TiO(2), chitosan-redox-clusters and chitosan-clay-aerogel microspheres are described and discussed on the basis of their textural and structural properties, thermal and chemical stability and their performance in catalysis and adsorption.

Chitosan Bio‐Based Organic–Inorganic Hybrid Aerogel Microspheres

We report the synthesis of a new trialkoxysilylated ionic liquid based on disilylated guanidinium and monosilylated sulfonimide species. This compound allowed the successful preparation of new periodic mesoporous organosilicas containing covalently anchored ion-pair through both organo-cationic and organo-anionic moieties which have never been reported up to now. Two classes of hybrid materials containing guanidinium-sulfonimide ion-pairs (IPs) have been synthesized. The first type of material was prepared by grafting the silylated IP onto both MCM-41-type and SBA-15-type silicas according to a surface sol-gel polymerization. The second class was synthesized following a one-pot sol-gel procedure using silylated IP and tetraethoxysilane as framework precursors. These latter materials correspond to so-called periodic mesoporous organosilicas (PMOs) and gave "organo-ionically" modified MCM-41 and SBA-15 related solids. The materials were characterized by a series of techniques including XRD, nitrogen sorption, solid-state NMR, FTIR, transmission electronic microscopy, and elemental analysis. The highest structural regularity in terms of pore size distribution and channel size homogeneity was observed for IP-PMOs possessing SBA-15-type architecture due to an enhanced trialkoxysilylated IP precursor/surfactant interaction. Solvatochromic experiments with Reichardt's dye showed good accessibility of the silica-supported ion-pair and suggested the formation of monophasic materials.

Jérôme Brandner

Papers

Hybrid Materials and Periodic Mesoporous Organosilicas Containing Covalently Bonded Organic Anion and Cation Featuring MCM-41 and SBA-15 Structure