Diphenyl-2-pyridylphosphine as a bidentate ligand in the coordination of dicobalt octacarbonyl; X-ray crystal structures of Co-2(CO)(4)(mu-P,N-PPh(2)py){mu-HC=CSiMe3}, and Co-4(CO)(10)(mu-P,N-PPh(2)py)

Under mild conditions, the reaction of Co-2(CO)(s) with HC=CSiMe3 in the pr esence of PPh(2)py gave a binuclear cobalt carbonyl complex, Co-2(CO)(4)(et a(2)-mu(2)-HC=CSiMe3)(mu-PPh(2)py) (1a), which has both zero-valent cobalt centers coordinated by a bidentate ligand, PPh(2)py. PPh(2)py is also an ef fective ligand in promoting the yield of 2,5-bis(trimethylsilanyl)cyclopent a-2,4-dien-1-one. A cobalt cluster complex, Co-4(CO)(10)(mu-P,N-PPh(2)py) ( 9) was obtained when two equivalents of Co-2(CO)(8) were reacted with PPh(2 )py at a higher temperature. The phosphorus and nitrogen atoms of the ligan d coordinate to cobalt in the basal and apical positions, respectively. The se two compounds, la and 9 were characterized by spectroscopic means as wel l as X-ray crystal structure determination. (C) 1999 Elsevier Science S.A. All rights reserved.