Dimethylplatinum (II) complexes with isocyanocoumarin ligands: the crystal structure of cis-dimethylbis-(7-diethylamino-3-isocyanocoumarin)platinum(II)

Platinum complexes that contain isocyanocourmarin ligands have been prepared. [Pt2Me4(μ-SMe2)2] and [PtPh2(SMe2)2] react with ligands L, (L = 7-diethylamino-3-isocyanocoumarin, Idc; 7-isocyano-4-methylcoumarin, Mic; 7-isocyano-4-trifluoromethylcoumarin, Tic; 3-chloro-4-methyl-7-isocyanocoumarin, Cmic), to give PtR2L2, monomers in high yield. The NMR and IR spectra of these complexes are consistent with cis stereochemistry. The UV–Vis absorption spectra of the complexes show bands assigned to ligand-centered transitions. Excitation into the absorption bands of the Idc complexes gives emission at room temperature in methylene chloride solution. The oxidative addition reaction of two of these complexes with methyl iodide has been studied. Platinum (IV) species with fac geometry have been isolated and characterized. Cis-dimethylbis-(7-diethylamino-3-isocyanocoumarin)platinum(II) was characterized by X-ray diffraction.