Titanium complexes zeolite structures

Supported metal complexes and clusters with well-defined structures offer the advantages of catalysts that are selective and structures that can be understood in depth. Such catalysts can be synthesized precisely with organometallic precursors, as illustrated in this review. Synthetic methods are illustrated with examples, including silica-supported chromium and titanium complexes for alkene polymerization rhodium carbonyls bonded predominantly at crystallographically specific sites in a zeolite and metal clusters, including Ir4, Rhg, OsjC, and bimetallics. 

The synthesis of titanium silicalites TS-1 [10] and TS-2 [84-85], with MFI and MEL structure respectively, opened new opportunities in the oxidations with H O. TS-1 and TS-2, the former being the most studied, show similar properties in catalysis. Catalytic sites are isolated titanium atoms, incorporated into the zeolitic framework, in a channel system of about 0.55 nm average diameter [86-88], Different Ti-peroxo species, at lattice position, result from complex equilibria between TS-1, H O, and protic molecules [89-91],... 

With recent advancement in the measurement techniques and the data analysis methods ESR spectroscopy is an increasingly important tool in the studies on catalysis and solid surfaces. This chapter focuses on the following five specific subjects relevant to the ESR applications in catalysis and environmental science (a) nitric oxide (NO) adsorbed on zeolites, (b) Cu(I)-NO complexes formed in zeolites, (c) structure and dynamics of organic radicals in zeolites, (d) titanium dioxide (Ti02) semiconductor photo-catalysis, and (e) the superoxide (O2 ) ion radical. 

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