Formation and cleavage of platinacycles containing a fluorinated imine.: Crystal structure of [PtMe(3,4,5-C6HF3CH=NCH2C6H5)PPh3]

The reaction of [Pt2Me4(mu-SMe2)(2)] with the ligand 3,4,5-C6H2F3CH-NCH2C6H5 (L) yielded the cyclometallated platinum(II) compound [PtMe(3,4,5-C6HF3CH=NCH2C6H5)SMe2] (1), in which the imine acts as a [C.N]-bidentate ligand. Compounds [PtMe(3,4,5-C6HF3CH=NCH2C6H5)DMSO] (2) (DMSO = dimethyl sulfoxide) and [PtMe(3,4,5-C6HF3CH=NCH2C6H5)PPh3] (3) were obtained from a displacement reaction of SMe2 for DMSO or PPh3. respectively. Oxidative addition of methyl iodide to compounds 1-3 produced, respectively, [PtMe2I(3.4.5-C6HF3CH=NCH2C6H5)SMe2] (4a/4b) as two isomers, [PtMe2I(3,4,5-{C6HF3CH=NCH2C6H5)}(2)] (5) and [PtMe2I(3,4,5-C6HF3CH NCH2C6H5)PPh3] (6). Platinum(II) metallacycles can be cleaved upon reaction with an excess of PPh3 or with the diphosphine dppe to yield, respectively, compounds [PtMe(3,4,5-C6HF3CH-NCH2C6H5)(PPh3)(2)] (7) and [PtMe(3,4,5-C6HF3CH-NCH2C6H5)dppe] (8) in which the imine acts as a monodentate [C] ligand. Analogous compounds Could not be obtained for platinum(IV) since in this case neither PPh3 nor dppe can cleave the metallacycle. The reaction of 4a/4b with dppe produced [{PtMe2I(3,4,5-C6HF3CH=NCH2C6H5)}(2)dppe] (11), a binuclear compound in which the diphosphine bridges two platinum(IN) moieties with the imine acting as a [C,N]-bidentate ligand. All compounds were characterised by analytical and spectroscopic techniques and compound 3 was also characterised crystallographically. (C) 2002 Elsevier Science Ltd. All rights reserved.