Cyclometallated platinum(II) compounds with imine ligands derived from amino acids: Synthesis and oxidative addition reactions

The reactions of [PtMe2(mu-SMe2)](2) with imines 4-ClC6H4CH=NCHRCO2Me (R = H (1a), Me (1b), Pr-i (1c), CH2C6H4(4'-OH) (1d), C6H5 (1e), CH2C6H5(1f)) derived from natural amino acids produced under mild conditions cyclometallated platinum(II) compounds [PtMe{kappa(2)-(C,N)-4-ClC6H3CH=NCHRCO2Me}(SMe2)] (2a-2f). These compounds gave the corresponding phosphine derivatives [PtMe{kappa(2)-(C,N)-4-ClC6H3CH=NCHRCO2Me}(PPh3)] (3a-3f). The corresponding cyclometallated platinum(IV) compounds [PtMe2I{kappa(2)-(C,N)-4-ClC6H3CH=NCHRCO2Me}(PPh3)] (4) arising from intermolecular oxidative addition of methyl iodide were obtained with a high degree of stereo selectivity. Analogous results were obtained for imine 2,6-Cl2C6H3CH=NCH(CH2C6H5)CO2Me (1g) in a process involving intramolecular oxidative addition of a C-Cl bond. The obtained compounds were fully characterized including structure determinations for compounds 3f, 4d and 4f. (C) 2009 Elsevier B.V. All rights reserved.