Insertion of CS2 into a metal acetylide bond and conversion of the bonding mode of S2CCCPh from η2 to η3

Photolysis of a benzene solution containing [(L)Mo(CO)(3)(CdropCPh)] (L=eta(5)-C5H5 1; eta(5)-C5Me5 2) and CS2 leads to the formation of dithiopropiolato containing complexes, [(L)MO(CO)(2)(eta(2)-S(2)CCdropCPh)] (L=eta(5)-C5H5 4; L = eta(5)-C5Me5 5). In presence of air, [(eta(5)- C5H5)Mo(CO)(3)(CdropCPh)] reacts with CS2 to give 4 as the major and [(eta(5)-C5H5)Mo(O)(eta(3)-S(2)CCdropCPh)] (6) as minor products. Similarly, [eta(5)-C5Me5)Mo(CO)(3)(CdropCPh)] reacts with CS2 under aerobic conditions to give compound 5 along with [(eta(5)- C5Me5)Mo(O)(eta(3)-S(2)CCdropCPh)] (7) as minor product. When solutions of 4 or 5 are photolysed under a constant purge of air, 4 gives 6, and 5 gives 7 in high yields. Room temperature stirring of 5 with [W(CO)(5)(THF)] forms [eta(5)-C5Me5)MO(CO)(2)CS2 {W(CO)(5)}(2)Cdrop CPh] (9). All new compounds have been characterised by IR and H-1-NMR spectroscopy and the structures of 4, 6, 7 and 9 have been established crystallographically. (C) 2003 Elsevier B.V. All rights reserved.