Mesoporous organic-inorganic hybrid materials, a new class of materials characterized by large specific surface areas and pore sizes between 2 and 15 nm, have been obtained through the coupling of inorganic and organic components by template synthesis. The incorporation of functionalities can be achieved in three ways: by subsequent attachment of organic components onto a pure silica matrix (grafting), by simultaneous reaction of condensable inorganic silica species and silylated organic compounds (co-condensation, one-pot synthesis), and by the use of bissilylated organic precursors that lead to periodic mesoporous organosilicas (PMOs). This Review gives an overview of the preparation, properties, and potential applications of these materials in the areas of catalysis, sorption, chromatography, and the construction of systems for controlled release of active compounds, as well as molecular switches, with the main focus being on PMOs.

Ordered mesoporous CMK carbons and periodic mesoporous organosilica (PMO) materials have been characterized by combining nitrogen (77.4 K) and argon (87.3 K) adsorption with recently developed quenched solid density functional theory (QSDFT). Systematic, high-resolution water adsorption experiments have been performed in the temperature range from 298 to 318 K in order to ascertain the effect of surface chemistry (using periodic mesoporous organosilicas (PMOs) of given pore size) and pore size/pore geometry (using CMK-3, CMK-8 carbons) on the adsorption, pore filling, condensation and hysteresis behavior. These data reveal how the interplay between confined geometry effects and the strength of the adsorption forces influence the adsorption, wetting, and phase behavior of pore fluids. Further, our results indicate that water adsorption is quite sensitive to both small changes in pore structure and surface chemistry, showing the potential of water adsorption as a powerful complementary tool for the characterization of nanoporous solids.

Durch die Verknüpfung anorganischer und organischer Bausteine mithilfe der templatgesteuerten Synthese gelangt man zu einer neuen Materialklasse, den mesoporösen organisch‐anorganischen Hybridmaterialien, die sich durch große spezifische Oberflächen sowie Porengrößen zwischen 2 und 15 nm auszeichnet. Das Einbringen der organischen Reste lässt sich auf drei Wegen erreichen: Durch die nachträgliche Anbindung organischer Komponenten an eine reine Silicamatrix (Pfropfung), durch die gleichzeitige Umsetzung kondensationsfähiger anorganischer Silicaspezies und silylierter organischer Verbindungen (Cokondensation, Eintopfsynthese) und durch die Verwendung bissilylierter organischer Vorstufen, die zu periodisch mesoporösen Organosilicas (PMOs) führt. Dieser Aufsatz gibt einen Überblick über die Herstellung, die Eigenschaften sowie die Anwendungsmöglichkeiten im Bereich der Katalyse, Sorption, Chromatographie, des Aufbaus von Systemen zur kontrollierten Wirkstoffabgabe sowie molekularer Schalter, wobei das Hauptaugenmerk auf PMOs liegt.

Periodic mesoporous organosilicas (PMOs) represent a new class of organic-inorganic hybrid materials suitable for a broad range of applications such as chromatography, catalysis, sensing and microelectronics. Unlike in organic functionalized mesoporous silica phases obtained via grafting or co-condensation procedures the organic groups in PMOs are direct parts of the 3D framework structure, thus giving raise to enormous possibilities to tune their chemical and physical properties in designated ways by varying the structure of the precursors. In this review the distinctive features of PMOs are discussed, the latest developments concerning compositions, structures, morphologies and potential applications are figured out and finally a brief outlook of future aspects is given.

The first example of a highly ordered periodic mesoporous thiophene-bridged organosilica (PMO) with large pores is reported. The synthesis was carried out under acidic conditions using a polyalkylene oxide triblock copolymer (Pluronic P123) as supramolecular structure-directing agent. Materials with pore sizes between 5 and 6 nm and specific surface areas in the range of 400-550 m 2 /g were obtained.The analysis of the TG/MS data demonstrates a relatively high thermal stability (up to 400 °C in air) of the mesoporous organosilica before a decomposition of the organic moieties occurs.

The first syntheses of highly ordered bifunctional periodic mesoporous organosilicas (PMOs) containing different amounts of aromatic thiophene and benzene bridging groups are reported. Employing the triblock copolymer Pluronic P123 as well as the oligomeric Brij 76 surfactant under acidic conditions as supramolecular structure-directing agents, the syntheses of two series of bifunctional aromatic PMO materials with pore sizes in the range of 4.8-5.4 and 3.3 nm, respectively, have been realized. Independent of the molar ratios of the organosilanes in the initial reaction mixtures, highly ordered PMO materials with 2D hexagonal mesostructures have been obtained in all cases. After a one-off calibration based on 29 Si MAS NMR measurements, the quantification of the organic functional groups has been carried out for the first time, in case of PMO materials, using Raman spectroscopic methods.

The first synthesis of a chiral periodic mesoporous organosilica (PMO) carrying benzylic ether bridging groups is reported. By hydrolysis and condensation of the new designed chiral organosilica precursor 1,4-bis(triethoxysilyl)-2-(1-methoxyethyl)benzene (BTEMEB) in the presence of the non-ionic oligomeric surfactant Brij 76 as supramolecular structure-directing agent under acidic conditions, an ordered mesoporous chiral benzylic ether-bridged hybrid material with a high specific surface area was obtained. The chiral PMO precursor was synthesized in a four-step reaction from 1,4-dibromobenzene as the starting compound. The evidence for the presence of the chiral units in the organosilica precursor as well as inside the PMO material is provided by optical activity measurements.

Like Honeycomb is how the pore structures of silica‐based mesoporous organic–inorganic hybrid materials often appear. In the Review on page 3216 ff., M. Fröba and co‐workers give an overview of their preparation. The cover picture shows hybrids whose pores are functionalized with cyclam (ligand), sulforhodamine B (laser die), and a cinchona derivative (for heterogeneous asymmetric catalysis). Particular attention is given to the class of periodic mesoporous organosilicas (PMOs).