Conversion of C C to CO in alkynyl-metal complexes: oxidation of carbon chains capped by carbon-tricobalt clusters

Treatment of Co(3)(mu(3)-CC[triple bond]CR)(mu-dppm)(CO)(7) with O(2) (air) in the presence of [FcH]PF(6) afforded Co(3){mu(3)-CC(O)R}(mu-dppm)(CO)(7) by the formal conversion -C[triple bond]C- + O-O --> >C-O + C[triple bond]O. In this way, complexes with R = Ph, Fc, and W(CO)(3)Cp, bis-clusters {Co(3)(mu-dppm)(CO)(7)}(2){mu(3):mu(3)-[[triple bond]C(O)(C[triple bond]C)C[triple bond]]}, {Co(3)(mu-dppm)(CO)(7)}(2){mu(3):mu(3)-[[triple bond]C(O)(C[triple bond]C)(x)C(O)C[triple bond, length as m-dash]]} (x = 1, 2), and {Co(3)(mu-dppm)(CO)(7)}(2){mu(3):mu(3)-[[triple bond]CC(O)C[triple bond, length as m-dash]CC(6)H(4)C[triple bond]CC(O)C[triple bond]]}, and heterometallic bis-clusters {Co(3)(mu-dppm)(CO)(7)}{mu(3):mu(3)-[[triple bond]CC(O)C[triple bond]CC[triple bond]]}{M(3)(mu-H)(3)(CO)(9)} (M = Ru, Os) have been prepared. Single-crystal XRD structure determinations of several products are reported together with that of precursor {Co(3)(mu-dppm)(CO)(7)}(2){mu(3):mu(3)-[[triple bond]C(C[triple bond]C)(2)C(6)H(4)(C[triple bond]C)(2)C[triple bond]]}.Michael I. Bruce, Paul A. Humphrey, Natasha N. Zaitseva, Brian K. Nicholson, Brian W. Skelton and Allan H. Whit