DECOMPOSITION PATHWAYS OF PLATINUM(II) COMPLEXES CONTAINING ALKYL ANDHALIDE LIGANDS INVESTIGATED BY ELECTROSPRAY MASS-SPECTROMETRY - THE X-RAY CRYSTAL-STRUCTURE OF CIS-[PTCL(CH2C(O)CH2CL)(PPH3)(2)]

The platinum(II) alkyl-halide complexes cis-[PtCl{CH2C(O)CH2Cl}(PPh3)( 2)], cis-[PtCl{CH2C(O)CH3}(PPh3)(2)], trans-[PtI(Me)(PPh3)(2)], [Pt{Et SCH2C(O)CH2}Br(PPh3)] and [Pt{MeSCH2C(O)CH2} I(PPh3)] have been invest igated by electrospray mass spectrometry (ESMS). For all complexes, lo ss of halide ion provides the initial ionization pathway and the resul ting ions may contain coordinated ligands from the solvent (acetonitri le, ammonia and added pyridine). At high cone voltages, all complexes undergo cyclometallation of one of the triphenylphosphine ligands. How ever, for the chloroacetonyl complex cis-[PtCl{CH2C(O)CH2Cl}(PPh3)(2)] , fragmentation to the ion [PtCl(PPh3)(2)](+) preceeds cyclometallatio n. It is proposed that this complex fragments aia initial oxidative ad dition of the C-Cl bond, forming an unstable platina (IV)cyclobutan-3- one (oxodimethylenemethane) complex, which undergoes reductive elimina tion of cyclopropanone. The X-ray crystal structure of cis-[PtCl{CH2C( O)CH2Cl}(PPh3)(2)] is also reported. (C) 1997 Elsevier Science Ltd.