Synthesis of dimethylplatinum(IV) compounds, [{PtMe2X2}n], [{PtMe2XY}n], and, in solution, fac-[PtMe2X(H2O)3]+, where X and Y are anionic ligands

Abstract

Oxidative addition of X2 (X = Cl, Br, I) to cis-[PtMe2L2] (L = pyridine, py, or L2 = N,N,N′,N′-tetramethylethylenediamine (tmen) gave [PtMe2X2L2]. For X = Br, I, treatment with aqueous HClO4 gave insoluble [{PtMe2X2}n], but for X = Cl, [PtMe2Cl2(H2O)2] remained in solution, with [{PtMe2Cl2}n] depositing only from concentrated solution. [PtMe2L2] (L = py, 1/2(tmen)) with water gave [PtMe2(OH)2L2], which, on treatment with HClO4 gave cis-[PtMe2(H2O)4](ClO4)2 in solution. Water also reacted with [PtMe2(nbd)] (nbd = norbornadiene) to give [{PtMe2](OH)2}n]•mH2O. Alcohols ROH (R = Me, Et) with cis-[PtMe2py2] gave [PtMe2(OR)(OH)py2], which reacted with aqueous HClO4 solution to give fac-[PtMe2(OR)(H2O)3]ClO4 in solution. Addition of chloride to this solution caused precipitation of [{PtMe2(OR)Cl}n]. Reaction of [{PtMe2XY}n] with AgNO3 in water gave fac-[PtMe2X(H2O)3](NO3) in solution (X = Y = Cl, Br, I or Y = Cl, X = OR); for X = I added acid was necessary to prevent precipitation of [{PtMe2I(OH)}n]. Reaction of a solution of fac-[PtMe2Br(H2O)3](NO3) with AgNO2 gave fac-[PtMe2(NO2)(H2O)3](NO3) in solution, but an analogous reaction with AgSCN gave a complex in solution formulated as fac-[PtMe2(SCN)(H2O)3](NO3) only in low yield. Key words: platinum, methyl, pyridine, aqua, alkoxide, oxidative addition, NMR.