Molybdenum alkoxides characterization

The compounds of these two elements belong apparently to the most studied and most fully characterized alkoxoderivatives of metals. The particular features of their synthesis and physicochemical properties are discussed in detail in a large number of review publications authored by Chisholm [370] who made tremendous contributions to the development of the chemistry of these substances. The synthetic routes to the bimetallic alkoxide derivatives of molybdenum and tungsten (VI) along with the discussion of their physicochemical properties and application prospects are also reviewed in [1638, 908],... 

The homoleptic derivatives of Mo and W(VI) are rather scarcely studied. The only structurally characterized complex, W(OMe)5, possesses the molecular structure analogous to those of alkoxide halids, i.e. a dimer built up of two edge-sharing octahedra. The structure of monooxo homometallic derivatives is unknown and their individuality appears questionable. The only dioxocom-plex of molybdenum(V) isolated as pyridin solvate demonstrates the [Ti(OMe)w]-type structure (Table 12.19). 

Preparation, Characterization, and Reactions of Dialkylamides and Alkoxides of Molybdenum and Tungsten... 

An impressive synthetic advance is the complete cleavage of the N—N bond of N2 by well-characterized, isolable compounds. The three-coordinate molybdenum(III) tris-anilide complex (3a) reacts quantitatively with 0.5 equivalents of N2 at ambient temperature to give the molyb-denum(VI) nitride (5a).There is no evidence that analogous tris-alkoxomolybdenum(III) and tris-thiolatomolybdenum(III) conmlexes can cleave N2, although the alkoxide can cleave N2 in combination with the anilide.Steric effects play an important role, as the related anilide complex (3b) does not split The mechanism of the reaction involves the formation of a... 

A vanadium(v)-molybdenum(vi) heterometallic oxo-alkoxide [V2Mo2(0)g (0Me)2 (0CH2)3C(CH20H) 2] has also been characterized. The V2M02O16 core involving octahedral metals is reminiscent of the Ti40ie core of titanium tetraUcoxides. ... 

The molybdenum neopentyUdene complex Mo(CHBu )(NR)(OBu )2 is the active catalyst used in a fascinating development for the synthesis of 11-Vt semiconductor clusters (ZnS, CdS, PbS) and silver and gold nanoclusters of predictable size within microdomains in films of block copolymers prepared by ROMP. Block copolymers of norbomene and a functionalized norbomene that wiU complex with a metal-containing compound were prepared and characterized as monodisperse materials. The functionalized component (amine, alkoxide, or thiolate) then sequestered the metal and the metallated block copolymer was cast into a film which was subsequently treated with H2S to convert the metal into the sulfide. The molybdenum complexes have also featured in the development of the synthesis of side-chain liquid crystal polymers by living ROMP.98 99... 

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