Osmium halide-bridged complexes

Binding energy, pentacarbonyliron, 6, 3 Binuclear complexes bis-Cp titanium halides, 4, 522 with Ni-M and Ni-C cr-bonds heterometallic clusters, 8, 115 homometallic clusters, 8, 111 Binuclear dicarbonyl(cyclopentadienyl)hydridoiron complexes, with rand C5 ligands, 6, 178 Binuclear iridium hydrides, characteristics, 7, 410 Binuclear monoindenyl complexes, with Ti(IV), 4, 397 Binuclear nickel(I) carbonyl complexes, characteristics, 8, 13 Binuclear osmium compounds, with hydrocarbon bridges without M-M bonds, 6, 619... 

Alkyl halides also add to dinudear compounds. Additions can occur across the metal-metal bond of homodinuclear complexes, as shown in Equation 7.22, or across the metal-metal bond of heterodinudear compounds, as shown in Equation 7.23. Oxidative additions of dihaloalkanes across two metal centers to generate bridging methylene complexes - have been reported for complexes of iron (Equation 7.24) and osmium. Addition of a higher alkyl dihalide to an odd-electron, dinudear cobalt system (Equation 7.25) " has also been reported. In this case, the stereochemical outcome suggests that the first substitution process occurs by a radical mechanism. 

Insertion of carbon monoxide into the bridging-methylene ligands was found to be up to 100 times faster if, instead of the bridging carbonyl, a bridging halide ion is present [59,60]. The osmium methylene complex 10 was found to add carbon monoxide rapidly affording the ketene complex 11 (reaction 8.30) [61]. 

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