Investigations of P-P bond formation reactions in the coordination sphere of transition metals

The reaction of [CpW(CO)(3)](-) with PCl3 leads to the transition metal sub stituted dichlorphosphines [{CpW(CO)(3)}PCl2] (1) and [{Cp(CO)(3)W}PCl2{WCl - (CO)(2)Cp}] (2). The X-ray structure of 2 reveals the Lewis acid/base cha racter of this compound. Reactions of 1 and [Cr(CO)(5)Cp*PCl2], respectivel y, with metalates of the type [M(CO)(3)Cp'](-) (M' = Mo, W; Cp' = eta(5)-C( 5)H(4)tBu) afford the cyclo-P-3 complexes [(eta(3)-P-3)MCp'(CO)(3)] (3) (M =W) and (4) (M = Mo) and the compounds [{mu,eta(2)-P-2{Cr(Co)(5)}(2)- (Mo(C O)(2)Cp)(2)}] (5) and [{mu(3)-PW(CO)(3)CP'}{W(CO)(2)CP'}2] (6), respectivel y. Complex 6 possesses a planar homoleptic W3P moiety revealing delocalised multiple bonds within the W2P-subunit. Reducing [(CO)(5)WPCl3] with magnes ium leads to the formation of the phosphinidene complex [{(CO)(5)W}(2)PCl], whereas the reduction of [CpW(CO)(3)PCl2] (1) with magnesium yields the cy clo-P-3 complex 3 together with P-4 phosphorus.