Osmium complexes nitriles

Surprisingly few osmium nitrile complexes are reported in the literature. 

THE OPTICAL SPECTRA AND VOLTAMMETRY OF MIXED HALIDE / NITRILE / CARBONYL OSMIUM(III) COMPLEXES. ADDITIVE AND NON-ADOinVE EFFECTS... 

The Optical Spectra and Voltammetry of Mixed Halide/Nitrile/Carbonyl Osmium(lll) Complexes. Additive and Non-Additive Effects G.A. Heath andD.G. Humphrey... 

The heterobimetallic complexes [N(n-Bu)4] [Os(N)R2(/u.-0)2Cr02] catalyze the selective oxidation of alcohols with molecular oxygen. A mechanism in which alcohol coordinates to the osmium center and is oxidized by B-hydrogen elimination (see -Hydride Elimination) is consistent with the data. The hydroxide adduct of OSO4, [0s(0H)204], with ferric cyanide and other co-oxidants catalyzes the oxidative dehydrogenation of primary aromatic and aliphatic amines to nitriles, the oxidation of primary alcohols to carboxylic acids, and of secondary alcohols to ketones. Osmium derivatives such as OsCb catalyze the effective oxidation of saturated hydrocarbons in acetonitrile through a radical mechanism. ... 

Oxidation of Alcohols and Amines using Osmium Tetroxide. Recent reports have shown that benzyUc amines can be oxidized to yield nitriles using an oxidizing system that includes catalytic osmium tetroxide. Unfortunately, only benzyUc amines could be successfully oxidized, with aliphatic derivatives giving rise to complex reaction mixtures (eq 41). ... 

Table 1 collects selected metric parameters and IR stretching frequencies (wno) fot a representative set of six-coordinated (6C) complexes of iron, ruthenium, and osmium, and few iron 5C-compounds. A number of Fe(III) heme proteins are involved in the regulation of the NO biosynthesis by the enzyme NO synthase, in NO transport (as vasodilator) in nitrophorins and in NO inhibition processes of cytochrome P450 and related enzymes (45). Heme enzymes are also intermediates in cyt cd nitrite reductases (NIRs), (46) and in NO reduction by a fungal cyt P450 NO reductase (47). The nonheme Fe(III) nitrile hydratase enzyme (NHase) is relevant to the microbial assimilation of organic nitriles, using... 

In subsequent studies, Esteruelas et at disclosed the synthesis of another cationic complex, [(IPr)Os(OH)(p-cymene)][OTf] 52, which was an efficient pre-catalyst for transfer hydrogenation of aldehydes with isopropanol, for hydration of nitriles into amides, and for a-alkylation of arylacetonitriles and methyl ketones with alcohols (Scheme 7.10). All these transformations were assumed to involve cationic hydrido intermediates formed by hydrogen transfer from one of the substrates to the osmium active species. 

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