Reactions of (Chloromethyl)platinum(II) Derivatives with Nucleophiles. Formation of (Dimethylamino)carbene Complexes UsingN,N,N‘,N‘-Tetramethylmethanediamine as Nucleophile and the X-ray Crystal and Molecular Structures ofcis-[(Ph3P)Pt(CH2NMe3)Cl2],cis(C,P)-[(Ph3P)Pt(CH2CH2C(O)NMe2)Cl], andtrans(As,CH2)-[(Ph3As)Pt(CHNMe2)(CH2NHMe2)Cl]PF6

Abstract

Reaction, in chloroform solution, of (COD)Pt(CH2Cl)Cl (5) with Me2NCH2NMe2 in the presence of 1 equiv (vs 5) of a monodentate ligand L (L = Ph3P, (p-MeOC6H4)3P, (p-FC6H4)3P, Et3P, Ph3As) gives the (dimethylamino)carbene complexes cis-[LPt(CHNMe2)Cl2] (1a−e) via the cyclic ylide intermediates [LPt(CH2NMe2CH2NMe2)Cl]Cl (2a−e). Major byproducts of the reaction are the (trimethylammonio)methyl ylide complexes cis-[LPt(CH2NMe3)Cl2] (11a−e). With L = Ph3As, carbene product 1e is accompanied by a second carbene complex, trans(As,CH2)-[(Ph3As)Pt(CHNMe2)(CH2NHMe2)Cl]Cl (25). When the reaction with L = Ph3P is carried out in acetonitrile, the amide chelate [(Ph3P)Pt(CH2CH2CONMe2)Cl] (24) is formed in addition to 1a and 11a. A deuterium labeling experiment indicates that formation of 24 involves condensation of a CH2Cl (or derived) moiety with a molecule of solvent. The structures of complexes 11a and 24, and of the hexafluorophosphate analogue (26) of complex 25, have been confirmed by X-ray crystallographic analys...