CRYSTAL-STRUCTURE OF SQUARE-PLANAR ,2-BIS(PHENYLSULFANYL)ETHANE]DIHALOGENPLATINUM(II) COMPLEXES - CIS-CHELATE EFFECT AND MUTUAL TRANS INFLUENCE

The crystal structures of six isomorphous 2-bis(phenylsulfanyl)ethane] dihalogenoplatinum(II) square-planar neutral complexes, i.e. dichloro (1), dibromo (2), diiodo (3), chlorobromo (4), chloroiodo (5) and brom oiodo (6) species, have been determined by the single-crystal X-ray di ffraction technique. Crystals are monoclinic, space group P2(1)/c, Z=4 , and their structures have been solved from three-dimensional counter data by Patterson and Fourier methods. Mixed dihalogeno species are d isordered as far as the positions of the two halides are concerned and refinements have been carried out with occupancies of 0.5. The platin um atom is coordinated by means of the two sulfur atoms of the bidenta te ligand and two halogen atoms in cis position. Comparison with other classes of platinum(II) complexes, carrying either chelating or monod entate thioetheric ligands and halides, allows to estimate a cis-chela te effect as well as the mutual trans influence of the different ligan ds.