Molybdenum complexes chemistry

We will focus on the development of ruthenium-based metathesis precatalysts with enhanced activity and applications to the metathesis of alkenes with nonstandard electronic properties. In the class of molybdenum complexes [7a,g,h] recent research was mainly directed to the development of homochi-ral precatalysts for enantioselective olefin metathesis. This aspect has recently been covered by Schrock and Hoveyda in a short review and will not be discussed here [8h]. In addition, several important special topics have recently been addressed by excellent reviews, e.g., the synthesis of medium-sized rings by RCM [8a], applications of olefin metathesis to carbohydrate chemistry [8b], cross metathesis [8c,d],enyne metathesis [8e,f], ring-rearrangement metathesis [8g], enantioselective metathesis [8h], and applications of metathesis in polymer chemistry (ADMET,ROMP) [8i,j]. Application of olefin metathesis to the total synthesis of complex natural products is covered in the contribution by Mulzer et al. in this volume. 

Molybdenum co-factor (Moco), 77 33 Molybdenum complexes, 26 927-929, 949 Molybdenum(III) complexes, 17 26-27 Molybdenum compounds, 17 19-43 in advanced structural and heating materials, 17 38-39 in anticorrosion agents, 17 39 biological aspects of, 17 31-34 biological uses for, 17 39-40 biomedical uses for, 17 40 catalytic applications of, 17 38 chemistry of, 17 29-31... 

Molybdenum(V) chemistry is dominated by oxo complexes many of these exist as dimers, but monomeric species can be isolated from strongly addic solutions or under nonaqueous conditions. Non-oxo compounds are also known, both as monomers and as dimers or polymers with halide or sulfur bridges. ESR spectroscopy has been used extensively to investigate the properties of monomeric Mov systems, and has shown the participation of this oxidation state in the reactions of the oxomolybdoenzymes (see Section 36.6.7). 

Among the metals which have achieved prominence only recently, molybdenum must certainly occupy first place. It has attracted interest chiefly because of its role in biological processes and also because it shows a great variety of oxidation states and coordination numbers. Steifel s extensive review of molybdenum complexes covers their chemistry up to 1977.3 Because of their use in nuclear medicine, the complexes of technetium have received recent interest.4... 

Group 4, surface chemistry on oxides, 12, 515 Group 5, surface chemistry on oxides, 12, 524 molybdenum, surface chemistry on oxides, 12, 529 into nickel complexes, 8, 59-60 with palladium, GO insertion, 8, 200 tungsten, surface chemistry on oxides, 12, 531 on zinc compounds, 2, 366 Alkoxido-imido tungsten complexes structure and properties, 5, 754—755 synthesis, 5, 750/... 

Pope, Michael T., Molybdenum Oxygen Chemistry Oxides, Oxo Complexes, and... 

Molybdenum complexes are the most effective catalysts known for the selective epoxidation of olefins with alkyl hydroperoxides (210-212). Commonly known is the Arco or Halcon process for the large-scale manufacture of propylene oxide from propylene. This process uses t-BuOOH or ethyl benzene hydroperoxide (EBHP) as an oxidant and Mo(CO)6, for example, as a source of Mo. The Mo(CO)6 acts as a catalyst precursor, which is converted into a soluble active form by complexation with diols (3). Chemists have designed several supported versions of the catalysts for this epoxidation chemistry. A clear classification can be made on the basis of the nature of the support. 

Reviews have appeared of the photophysics of molybdenum complexes, primary and secondary processes in organometallic chemistry, flash photolysis of Pe(CO)5 and Cr(CO)g, dinuclear manganese carbonyl compounds, the photochemistry of metal complexes isolated in low temperature matrices, cluster complexes, diene complexes, photoproduction of coordinativeiy unsaturated species containing rhodium or iridium, and redox chemiluminescence of organometallic compounds.Synthetic and metal organic photochemistry in industry has also been reviewed. 

Pope, M. T. Molybdenum Oxygen Chemistry Oxides, Oxo Complexes, and Polyoxoanions In Prog. Inorg. Chem. Lippard, S. J., Ed. Wiley New York, 1991pp 181-257. 

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