Composés de coordination de molécules soufrées. II. Complexes pseudo-tétraédriques et plan du nickel(II) avec quelques dithiole-1,2 thiones-3

The study of the far infrared spectral region permits one to distinguish between the pseudo-tetrahedral complexes NiI2L2 (L = R1R2C3S3 where R1 = CH3 and R2 = H, R1 = R2 = CH3, R1 = C4H3S and R2 = H) and the square planar complex NiI2L′2 (L′ = R1R2C3S3 where R1 = C6H5 and R2 = H). The electronic spectra recorded in the solid state confirm the distinction. The displacement of the band νC=S of the molecule 1,2-dithio-1-3-thione which enters the sphere of coordination is more marked in the complexes of cobalt(II) than in the corresponding nickel(II) complexes.