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

Abstract

The reactions of [PtMe 2(μ-SMe 2)] 2 with imines 4-ClC 6H 4CH NCHRCO 2Me (R = H ( 1a), Me ( 1b), i Pr ( 1c), CH 2C 6H 4(4’-OH) ( 1d), C 6H 5 ( 1e), CH 2C 6H 5( 1f)) derived from natural amino acids produced under mild conditions cyclometallated platinum(II) compounds [PtMe{κ 2-(C,N)-4-ClC 6H 3CH NCHRCO 2Me}(SMe 2)] ( 2a– 2f). These compounds gave the corresponding phosphine derivatives [PtMe{κ 2-(C,N)-4-ClC 6H 3CH NCHRCO 2Me}(PPh 3)] ( 3a– 3f). The corresponding cyclometallated platinum(IV) compounds [PtMe 2I{κ 2-(C,N)-4-ClC 6H 3CH NCHRCO 2Me}(PPh 3)] ( 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-Cl 2C 6H 3CH NCH(CH 2C 6H 5)CO 2Me ( 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.