Alkynyl and poly-ynyl derivatives of carbon-tricobalt clusters

A series of alkynyl-tricobalt carbonyl clusters, Co-3(mu(3)-CnR)(mu-dppm)(CO)(7) [R = Bu-t, Ph, C6H4I, C6H4C CPh, SiMe3, Fc, Au(PPh3)] containing three, five or seven carbons in the chain, have been prepared by elimination of phosphine gold(I) halides in reactions between Co-3(mu(3)-CBr)(mu-dppm)(CO)(7) and Au(C CR)(PPh3) or between Co-3{mu(3)-CC CAu(PR3)}(mu-dppm)(CO)(7) (R= Ph, tol) and IC CR' (R' = SiMe3, Fc).The use of poly-substituted arenes or ferrocenes has enabled preparation of the complexes 1,4-{(OC)(7)(mu-dppm)-Co-3(mu(3)-CC C)}(2)C6H3X-5 (X=H, Br), 1,3,5-{(OC)(7)(mu-dppm)Co-3(mu(3)-CC C)}(3)C6H3 and 1,1'-{(OC)(7)(mu-dppm)Co-3(mu(3)-CC C)}(2)Fc' [Fc' = Fe(eta-C5H4-)2]. The X-ray determined molecular structures of 12 of the complexes are reported. (c) 2006 Published by Elsevier B.V.