Photoinduced carbonylation of the carbyne ligand in (.eta.-C5H5)(CO)2W.tplbond.CTol

UV irradiation of solutions of Cp(CO)/sub 2/W=CTol (1) (Tol = rho-C/sub 6/H/sub 4/CH/sub 3/; Cp = eta-C/sub 5/H/sub 5/) in the presence of CO induces carbonylation of the carbyne ligand and formation of the binuclear complex (Cp-(CO)/sub 2/W)/sub 2/(eta-TolCC/O/CTol) (2). Complex 2 has been crystallographically characterized: triclinic, P anti 1, a = 8.773 (2) A, b = 12.042 (3) A, c = 14.866 (5) A, ..cap alpha.. = 91.81 (2)/sup 0/, ..beta.. = 94.12 (2)/sup 0/, ..gamma.. = 110.32 (2)/sup 0/, R/sub F/ = 4.63%, R/sub wF/ = 5.62% for 3075 reflections with F/sub o/ greater than or equal to 3 sigma(F/sub o/). The bridging ligand of 2 consists of two carbyne units linked by a CO with the latter not bonded to either metal. Irradiation of 1 in the presence of PPh/sub 3/ leads to rapid formation of the known ketenyl complex Cp(CO)/sub 2/(PPh/sub 3/)W(eta/sup 2/-TolCCO) (5). Complex 5 reacts further with CO to form the eta/sup 1/-ketenyl species Cp(CO)/sub 2/(PPh/sub 3/)W(eta/sup 1/-TolCCO). Photolysis of 1 in the presence of dppe (dppe = 1,2 bis(diphenylphosphino)ethane) yields the eta/sup 1/-ketenyl species Cp(CO)(dppe)W(eta/sup 1/-TolCCO), which readily loses dppe to give the novel binuclear eta/sup 2/-ketenyl species Cp(CO)(dppe)W(eta/sup 1/-TolCCO), which readily losesmore » dppe to five the novel binuclear eta/sup 2/-ketenyl derivative (Cp(CO)W(eta/sup 2/-TolCCO))/sub 2/(..mu..-dppe).« less