"Space—the final frontier." This preamble to a well-known television series captures the challenge encountered not only in space travel adventures, but also in the field of porous materials, which aims to control the size, shape and uniformity of the porous space and the atoms and molecules that define it. The past decade has seen significant advances in the ability to fabricate new porous solids with ordered structures from a wide range of different materials. This has resulted in materials with unusual properties and broadened their application range beyond the traditional use as catalysts and adsorbents. In fact, porous materials now seem set to contribute to developments in areas ranging from microelectronics to medical diagnosis.

Ordered porous materials for emerging applications

The Hydrothermal Synthesis of Zeolites: History and Development from the Earliest Days to the Present Time

This critical review is intended to attract the interest of organic chemists and researchers on green and sustainable chemistry on the catalytic activity of supported gold nanoparticles in organic transformations. In the general part of this critical review, emphasis is given to the different procedures to form supported gold nanoparticles and to the importance of the support cooperating in the catalysis. Also the convergence of homogeneous and heterogeneous catalysis in the study of gold nanoparticles has been discussed. The core part of this review is constituted by sections in which the reactions catalyzed by supported gold nanoparticles are described. Special emphasis is made on the unique ability of gold catalysts to promote additions to multiple C–C bonds, benzannulations and alcohol oxidation by oxygen (282 references).

Supported gold nanoparticles as catalysts for organic reactions

Surfactant-mediated synthesis methods have attracted much interest for the production of inorganic mesoporous materials, which can, on removal of the surfactant template, incorporate polymeric, organic, inorganic and organometallic guests' in their pores 1,2 . These materials-initially made of silica 3-5 , but now also available in the form of other oxides 6-9 , sulphides 10,11 , phosphates 12 and metals 13 -could find application in fields ranging from catalysis, adsorption and sensing technology to nanoelectronics. The extension of surfactant-mediated synthesis to produce inorganic-organic hybrid material (that is, materials that contain organic groups as an integral part of their framework structure) promises access to an even wider range of application possibilities. Such hybrid materials have been produced in the form of amorphous silicates (xerogels) that indeed display unique properties different to those of the individual components 14-20 , but their random networks with broad pore-size distributions severely limit the shape and size selectivity of these materials. Mesoporous hybrid materials with periodic frameworks have been synthesized, but the organic groups are all terminally bonded to the pore surface, rather than incorporated into the pore walls 21-26 . Here we describe a periodic mesoporous organosilica containing bridge-bonded ethene groups directly integrated into the silica framework. We are able to solvent-extract and ion-exchange the surfactant templates to create a stable and periodic mesoporous ethenesilica with high surface area and ethene groups that are readily accessible for chemical reaction. Recent syntheses of similar periodic mesoporous organosilicas 27,28 and the ability to incorporate a variety of bridging organic and organometallic species raise the prospect of being able to fuse organic synthesis and inorganic materials chemistry to generate new materials with interesting chemical, mechanical electronic, optical and magnetic properties.

Periodic mesoporous organosilicas with organic groups inside the channel walls

An MCM-41 type mesoporous silica nanosphere-based (MSN) controlled-release delivery system has been synthesized and characterized using surface-derivatized cadmium sulfide (CdS) nanocrystals as chemically removable caps to encapsulate several pharmaceutical drug molecules and neurotransmitters inside the organically functionalized MSN mesoporous framework. We studied the stimuli-responsive release profiles of vancomycin- and adenosine triphosphate (ATP)-loaded MSN delivery systems by using disulfide bond-reducing molecules, such as dithiothreitol (DTT) and mercaptoethanol (ME), as release triggers. The biocompatibility and delivery efficiency of the MSN system with neuroglial cells (astrocytes) in vitro were demonstrated. In contrast to many current delivery systems, the molecules of interest were encapsulated inside the porous framework of the MSN not by adsorption or sol−gel types of entrapment but by capping the openings of the mesoporous channels with size-defined CdS nanoparticles to physically block...

A mesoporous silica nanosphere-based carrier system with chemically removable CdS nanoparticle caps for stimuli-responsive controlled release of neurotransmitters and drug molecules.

Influence of the sorbate type on the XRD peak intensities of loaded MCM-41

The structure-controlling role of organic templates for the synthesis of porosils in the systems SiO2/template/H2O

One- and two-dimensional high-resolution solid-state NMR studies of zeolite lattice structures

On the basis of the predictions of statistical−thermodynamic models, it is postulated that excluded volume effects may play a significant role in the stability, interaction, and function of proteins. We studied the effects of confinement on protein un/refolding and stability. Our approach was to encapsulate a model protein, RNase A, in a mesoporous silica, MCM-48, with glasslike wall structure and with well-defined pores to create a crowded microenvironment. To the best of our knowledge, this is the first report where pressure perturbation and differential scanning calorimetric techniques are employed to evaluate the stability, hydration, and volumetric properties of the confined protein. A drastic increase in protein stability (∼30 °C increase in unfolding temperature) is observed. The increase in stability is probably not only due to a restriction in conformational space (excluded volume effect due to nonspecific interactions) but also due to an increased strength of hydration of the protein within the ...

Protein encapsulation in mesoporous silicate: the effects of confinement on protein stability, hydration, and volumetric properties.

Zeolite RUB-41, framework type code RRO, having a new framework structure has been synthesized as a calcination product using a layered silicate, RUB-39, as precursor. The precursor was obtained from hydrothermal synthesis using dimethyldipropylammonium hydroxide as structure directing agent. RUB-41, 18SiO2 per unit cell, crystallizes in the monoclinic space group P2/c with a = 7.345(1) A, b = 8.724(1) A, c = 17.125(1) A, and β = 114.2(1)°. The material has a 2-dimensional channel system with intersecting 8- and 10-membered ring pores. The pore openings determined from structure analysis are 5.8 A × 4.1 A (8MR) and 5.9 A × 4.1 A (10MR). The surface area determined from nitrogen adsorption experiments is 510 m2/g and the pore space is accessible for linear molecules. The material shows high sorption interaction for C4 alkenes and excludes i-butane from the pore system.

Synthesis and Crystal Structure of Zeolite RUB-41 Obtained as Calcination Product of a Layered Precursor: a Systematic Approach to a New Synthesis Route

Hermann Gies

Papers

Influence of the sorbate type on the XRD peak intensities of loaded MCM-41

The structure-controlling role of organic templates for the synthesis of porosils in the systems SiO2/template/H2O

One- and two-dimensional high-resolution solid-state NMR studies of zeolite lattice structures

Protein encapsulation in mesoporous silicate: the effects of confinement on protein stability, hydration, and volumetric properties.

Synthesis and Crystal Structure of Zeolite RUB-41 Obtained as Calcination Product of a Layered Precursor: a Systematic Approach to a New Synthesis Route