Synthesis and nucleophilic behavior of cis-[M(C6F5)(2)(Ph(2)PCHPPh(2))](-) (M=Pd, Pt): C-alkylation, metalation, and halogenation of coordinated bis(diphenylphosphino)methane. X-ray crystal structure of [Pt(C6F5)(2)(Ph(2)PCHIPPh(2))]center dot C5H12

The reaction of the neutral complexes cis-[M(C6F5)(2)(Ph(2)PCH(2)PPh(2))] [M = Pd (1a), Pt (1b)] with LDA (lithium diisopropylamide) or Li(t)Bu (tert-butyllithium) in THF readily affords the anionic derivatives [M(C6F5)(2)(Ph(2)PCHPPh(2))](-) by deprotonation of the coordinated bis-(diphenylphosphino)methane (dppm). The reactivity of the carbanionic center thus generated toward a variety of substrates has been studied. The reaction with alkyl halides such as MeI or EtI gives the neutral, C-alkylated complexes cis-[M(C6F5)(2)(Ph(2)PCHRPPh(2))] [M = Pd, R = Me (2a), Et (4a); M Pt, R = Me (2b), Et (4b)], and the reaction with ClAuPPh(3) or O(3)ClOAgPPh(3) gives the heterobimetallic species cis-M(C6F5)(2)[Ph(2)PCH(MPPh(3))PPh(2)] [M = Pd, M' = Au (5a), Ag (6a); M = Pt, M' = Au (5b), Ag (6b)], in which the [Ph(2)PCHPPh(2)](-) ligand acts as a bridging, tridentate-P,P',C ligand. The reactions with halogens (Cl-2, Br-2, I-2) or pentafluorophenyl halides (BrC6F5, IC6F5) produce the heterolytic cleavage of the X-X or X-C bond, giving the halogenated derivatives cis-[M(C6F5)(2)(Ph(2)PCHXPPh(2))][M = Pd, X = I (9a); M = Pt, X = Cl (7b), Br (8b), I (9b)]. The reaction of [Pt(C6F5)(2)(Ph(2)PCHPPh(2))](-) with C6F5CN occurs with C-F bond cleavage, and the para-substituted product M(C6F5)(2)[Ph(2)-PCH(C6F4CN-4)PPh(2)] (10b) is obtained. The X-ray crystal structure of 9b . C5H12 is reported.