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 CR)(mu-dppm)(CO)(7) with O-2 (air) in the presence of [FcH]PF6 afforded Co-3{mu(3)-CC(O)R}(mu-dppm)(CO)(7) by the formal conversion -C C- + O-O --> >C-O + C 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)-[ C(O)(C C)C ]}, {Co-3(mu-dppm)(CO)(7)}(2){mu(3):mu(3)-[ C(O)(C C)(x)C(O)C ]} (x = 1, 2), and {Co-3(mu-dppm)(CO)(7)}(2){mu(3):mu 3-[ CC(O)C CC6H4C CC(O)C ]}, and heterometallic bis-clusters {Co-3(mu-dppm)(CO)(7)}{mu(3):mu(3)-[ CC(O)C CC ]}{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)-[ C(C C)(2)C6H4(C C)(2)C ]}.