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

The reactions of [PtMe2(μ-SMe2)]2 with imines 4-ClC6H4CHNCHRCO2Me (R = H (1a), Me (1b), iPr (1c), CH2C6H4(4’-OH) (1d), C6H5 (1e), CH2C6H5(1f)) derived from natural amino acids produced under mild conditions cyclometallated platinum(II) compounds [PtMe{κ2-(C,N)-4-ClC6H3CHNCHRCO2Me}(SMe2)] (2a–2f). These compounds gave the corresponding phosphine derivatives [PtMe{κ2-(C,N)-4-ClC6H3CHNCHRCO2Me}(PPh3)] (3a–3f). The corresponding cyclometallated platinum(IV) compounds [PtMe2I{κ2-(C,N)-4-ClC6H3CHNCHRCO2Me}(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-Cl2C6H3CHNCH(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.

Graphical abstractThe synthesis of cyclometallated platinum(II) compounds containing imine ligands derived from natural amino acids is reported. Oxidative addition of methyl iodide to these compounds produces the corresponding platinum(IV) derivatives with a high degree of stereoselectivity.Figure optionsDownload full-size imageDownload as PowerPoint slide