Reactions of the mixed-metal alkyne-bridged complexes [(eta(5)-C5H5)(OC)(2)M{mu-C-2(CO2Me)(2)}Co(CO)(3)] (M = Mo or W) with Ph2PC (CBu)-Bu-t

Reaction of the mixed-metal alkyne-bridged complexes [(eta(5)-C5H5)(OC)(2)M {mu-C-2(CO2Me)(2)}Co(CO)(3)] (M = Mo or W) with Ph2PC=(CBu)-Bu-t in refluxi ng toluene gives the complexes [(eta(5)-C5H5)(OC)(2)M{mu-(BuCCC)-Bu-t(CO2Me )=C(CO2Me)PPh2} Co(CO)(2)], [(eta(5)-C5H5)(OC)(2)M{mu-C-2(CO2Me)(2)}Co(CO)( 2)(Ph2PC=(CBu)-Bu-t)](M=Mo or W) and [(eta(5)-C5H5)(OC)W{mu-C(CO2Me)=C(CO2M e)C=(CBu)-Bu-t) (mu-PPh2)Co(CO)(2)]. The structures of the two complexes, [ (eta(5)-C5H5)(OC)(2)Mo {mu-(BuCCC)-Bu-t(CO2Me)=C(CO2Me)PPh2} Co(CO)(2)] and [(eta(5)-C5H5)(OC)W{mu-C(CO2Me)=C(CO2Me)C=(CBu)-Bu-t}(mu-PPh2)Co(CO)(2)], have been determined by X-ray analysis. Possible reaction pathways for the formation of the new complexes are proposed and discussed. (C) 1999 Elsevie r Science S.A. All rights reserved.