CYCLOPALLADATION OF N,N,N',N'-TETRAMETHYLISOPHTHALTHIOAMIDE

N,N,N',N'-Tetramethylisophthalthioamide (Hmpt) was cyclopalladated wit h PdCl2 in hot dimethylsulphoxide to give [PdCl(mpt)]. The structure w as determined by X-ray analysis. The thioamide is metallated at C(2) t o act as an S-C-S tridentate anionic ligand. There is appreciable ster ic repulsion between the benzene ring H(4, 6) and the dimethylamino gr oups. The hydrogens and the methyl groups mutually deviate from the co ordination plane in opposite directions. The stability of the fused 5, 5-membered chelate ring formed by the S-C-S ligand seems to overcome t he steric hindrance. Derivatives were prepared by replacement of the c hloride ion with iodide, diethyldithiocarbamate, 4-tert-butylpyridine, or tri-n-butylphosphine, and characterized spectroscopically. The S-C -S-fused chelate ring was maintained in these derivatives.