Synthesis of the complexes 3-C3H5)(η6-7,9-C2B10H10Me2)>(M=Mo or W): crystal structure of 6-7,9-C2B10H10Me2)>

Article abstract of DOI:10.1016/0022-328X(94)88013-1

Treatment of the compounds 3-C3H5)> (M=Mo or W) with Na2<7,9-C2B10H10Me2> in tetrahydrofuran, followed by addition of Cl, affords the salts 3-C3H5)(η⁶-7,9-C2B10H10Me2)>.Reactions of 26-7,9-C2B10H10Me2)> with an excess of allyl bromide generate the complexes 6-7,9-C2B10H10Me2)> via an allyl-coupling process.The structure of the latter (M=W) has been determined by X-ray diffraction.The preparation of the molybdenum salt 6-7,9-C2B10H10Me2)> by this route was accompanied by the formation of small amounts of the complex 5-7,9-C2B9H9Me2)> resulting from ejection of a BH vertex from the cage.Indeed, it was observed that in CH2Cl2 solutions, the former species was slowly converted into the latter at ambient temperatures.Protonation (aqueous HBr) of the salts 3-C3H5)(η⁶-7,9-C2B10H10Me2)> in the presence of an atmosphere of CO also yields the compounds 6-7,9-C2B10H10Me2)>, but if the molybdenum compounds is protonated in the absence of CO the complex 5-7,9-C2B9H9Me2)> is formed directly.The NMR data for the new compounds are reported and discussed, as are the possible pathways of their formation. Key words: Molybdenum; Tungsten; Crystal structure; Cage compound; Carborane; Allyl