Ordered mesoporous and microporous molecular sieves functionalized with transition metal complexes as catalysts for selective organic transformations.

3. Soluble Metal Oxides 2459 3.1. Polyoxometalates 2459 3.2. Peroxotungstates 2459 3.3. Peroxomolybdates 2460 3.4. Methyltrioxorhenium 2461 3.5. Other Metal Oxides 2461 4. Metal Oxides Generated in Situ 2461 4.1. Selenium and Arsenic Compounds 2461 4.2. Simple Metal Salts 2462 5. Coordination Complexes 2463 5.1. Manganese Porphyrins 2463 5.2. Iron Porphyrins 2464 5.3. Manganese Salen Complexes 2466 5.4. 1,4,7-Triazacyclononane (TACN) Complexes 2466 5.5. Iron and Manganese Pyridyl-Amine Complexes 2468

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Metal-Catalyzed Epoxidations of Alkenes with Hydrogen Peroxide

This review provides an overview of different aspects of inclusion chemistry in ordered mesoporous host materials such as MCM-41 or MCM-48 (Mobil codes). A rich field of inclusion chemistry has been explored in this context, including sorption, ion exchange, imbibition followed by reduction, grafting of reactive metal alkoxides, halides etc., grafting of silane coupling agents (sometimes followed by subsequent reactions), grafting of reactive metal complexes, and polymerization in the channels. Finally, co-condensation of reactive species during the mesopore synthesis is a method to incorporate functionality into the walls of the channel system. Important applications of these modified and functionalized systems are heterogeneous catalysis and photocatalysis involving bulky grafted catalysts and/or the conversion of large substrates. Other potential applications include ion exchange and separations, removal of heavy metals, chromatography, stabilization of quantum wires, stabilization of dyes, and polymer...

Inclusion Chemistry in Periodic Mesoporous Hosts

The area of periodic mesoporous materials prepared by cooperative assembly in the presence of amphiphile molecules underwent dramatic growth. Among the silica-based materials, many types may be reg...

Periodic Mesoporous Silica-Based Organic−Inorganic Nanocomposite Materials

This review describes examples of remarkable acceleration of metal-catalyzed oxidation reactions by certain additives. In some cases, reactions proceed 2 or 10 times more rapidly in comparison with the process in the additive’s absence, in other cases, reactions become possible only in the presence of the additive. Varying ligands at the metal center or additives, one can not only dramatically improve yields of oxygenates but also control the selectivity of the reaction. Understanding mechanisms of the additive’s action is very important for search of new efficient catalysts and catalytic systems. Additives considered in the review can play roles of the ligands at metal ion or proton or electron transfer reagents and they mimic certain enzymes (the active center or its environment). Often the mechanism of the effect of additives on the reaction rate and the product yield is unknown, and the main aim of the review is to attract investigator’s attention in creating new efficient catalytic systems, which contain not only a metal ion but also a necessary “additive”.

http://shulpin.narod.ru/JMolCatal2002.pdf

Metal-catalyzed hydrocarbon oxygenations in solutions: the dramatic role of additives: a review

Epoxidation of terminal or electron-deficient olefins with H2O2, catalysed by Mn-trimethyltriazacyclonane complexes in the presence of an oxalate buffer

Practical heterogenisation of an active manganese triazacyclononane epoxidation catalyst via surface glycidylation

Publisher Summary As an alternative to porphyrin and phthalocyanine catalysts, the study of complexes of Mn and the cyclic triamine 1,4,7-trimethyl-1,4,7-triazacyclononane (tmtacn) is important. Here an immobilization of Mn-tmtacn based on zeolite Y has been proposed. However, a major problem is that hydrophilic matrix attracts H 2 O 2 . This is a drawback from the peroxide efficiency viewpoint. Therefore, a purely siliceous matrix seems more attractive. As pure SiO 2 lacks ion exchange capacity, reverting to other immobilization strategies is necessary, such as the covalent route. The chapter discusses various routes for covalent attachment of the tacn macrocycle to a pre-formed support matrix. This work is the first example of a covalently anchored, catalytically active nonheme Mn compound. Two different spacers are used to link the surface and the tacn: propyl (P) and glycidoxypropyl (GP). The affinity of the modified surface for metals is probed with the test ions Cu 2+ and Mn 2+ and styrene is the test substrate for the selective hydrocarbon oxidation. To improve the catalyst performance, the effect of reacting the anchored tacn with two molecules of propylene oxide (PO) was tested.

Immobilization of triazacyclononane-type metal complexes on inorganic supports via covalent linking: spectroscopy and catalytic activity in olefin oxidation

Y.V. Subba Rao

Papers

Epoxidation of terminal or electron-deficient olefins with H2O2, catalysed by Mn-trimethyltriazacyclonane complexes in the presence of an oxalate buffer

Practical heterogenisation of an active manganese triazacyclononane epoxidation catalyst via surface glycidylation

Immobilization of triazacyclononane-type metal complexes on inorganic supports via covalent linking: spectroscopy and catalytic activity in olefin oxidation