REACTIONS OF MOLYBDENUM AND TUNGSTEN PHOSPHENIUM COMPLEXES WITH SULFUR AND SELENIUM

The reactions of the phosphane [(Me(3)Si)(2)N](Ph)PCl with NaCpMo(CO)( 3) and NaCpW(CO)(3) give the respective metallophosphenium complexes C p(CO)(2)M{P(Ph)[N(SiMe(3))(2)]} (M = Mo (4a), W (4b)). The subsequent reactions of 4a,b with S and Se produce unexpectedly different product s: Cp(CO)(2)(S)M{P(Ph)[N(SiMe(3))(2)]} (M = Mo (7a)); Cp(CO)(2)MSP(Ph) [N(SiMe(3))(2)] (M = W (7b)); Cp(CO)(2)MSeP(Ph)[N(SiMe(3))(2)] (M = Mo (8a), W (8b)). The compounds have been fully characterized by element al analyses and spectroscopic data, and the molecular structures of 4a , 7a,b, and 8a have been determined by single-crystal X-ray diffractio n techniques. The molecular structure of 7a displays a long, terminal Mo-S bond, while 7b and 8a contain M-E-P three-membered rings.