Synthesis and reactivity of new trimethylplatinum(IV) complexes containing chiral Schiff bases as ligands: Crystal structure of (OC-6-44-C)-[PtIMe 3{κ 2-( R)-Ph 2P(C 6H 4)CH [dbnd]NC*H(Ph)Me-P,N}

Abstract

Reaction of the tetranuclear complex [PtIMe 3] 4 with the ligand ( S)- and ( R)-Ph 2P(C 6H 4)CH NC*H(Ph)Me in a 1:4 molar ratio yields the mononuclear neutral complexes in diastereoisomeric mixtures [PtIMe 3{κ 2-Ph 2P(C 6H 4)CH NC*H(Ph)Me-P,N}]. Iodide abstraction from mixture with AgBF 4 in the presence of pyridine (Py) induces a reductive elimination reaction with loss of ethane, leading to the cationic complex [PtMe(Py){κ 2-Ph 2P(C 6H 4)CH NC*H(Ph)Me-P,N}][BF 4] [C* = ( S)-, 3; ( R)-, 4]. When this reaction was carried out in the presence of PPh 3 a consecutive orthometallation reaction with loss of methane is produced, forming the cationic complex [Pt(PPh 3){κ 3-Ph 2P(C 6H 4)CH NC*H(C 6H 4)Me-C,P,N}][BF 4], [( S)-, 5; ( R)-, 6]. All species were characterised in solution by 1H and 31P{ 1H} NMR spectroscopy, elemental analysis and mass spectrometry. The crystal structure of the diastereoisomer (OC-6-44-C)-[PtIMe 3{κ 2-( R)-Ph 2P(C 6H 4)CH NC*H(Ph)Me-P,N}] has been determined by single-crystal X-ray diffraction.