VINYLIDENE COMPLEXES OF OSMIUM(0) DERIVED FROM 1-NAPHTHYL-CARBYNE OR 2-NAPHTHYL-CARBYNE COMPLEXES BY HYDRIDE ADDITION TO THE NAPHTHYL SUBSTITUENTS - THE CRYSTAL-STRUCTURE OF OS(=C=C10H8)(CO)(2)(PPH3)(2)

When treated with lithium triethylborohydride, the cationic carbyne co mplexes [Os(-CR)(CO)(2)(PPh3)(2)](+) (R = 1-naphthyl, 1; R = 2-naphthy l, 2) form 3 and 4, respectively, which both have the formula Os(C11H8 )(CO)(2)(PPh3)(2). NMR studies of these two isomeric vinylidene comple xes show that the product derived from the I-naphthyl carbyne cation i nvolves attack at the naphthyl ring in the position para to the carbyn e carbon to give 3, while that derived from the 2-naphthyl carbyne cat ion involves attack at the naphthyl ring in the position ortho to the carbyne carbon to give 4. The structure of 4 has been confirmed by an X-ray crystal structure determination. Addition of HCl to the vinylide ne complexes 3 or 4 results in the formation of the corresponding naph thylmethyl complexes, Os(CH2R)Cl(CO)(2)(PPh3)(2) (R = 1-naphthyl, 5; R = 2-naphthyl, 6). (C) 1998 Elsevier Science S.A. All rights reserved.