MULTINUCLEAR NMR-SPECTRA OF [PT(L)CL-3](-) (L EQUALS PYRIDINE-DERIVATIVES) COMPLEXES AND CRYSTAL-STRUCTURE OF -DI(HYDROXYMETHYL)PYRIDINE)(2)CL-2-CENTER-DOT-2H2O

Complexes of the type [Pt(L)Cl-3](-) (L = pyridine derivative) were sy nthesized and studied by C-13 and Pt-195 NMR spectroscopies. The Pt-19 5 signals were observed between - 1720 and -1897 ppm. No correlation b etween the delta(Pt) and the pK(a) of the protonated pyridine derivati ves was found. The chemical shifts vary with the substituents on the p yridine ligand. Compounds with substituents in ortho positions were ob served at lower fields, except for complexes containing hydroxy or ami ne groups. The latter compounds were observed at higher fields, close to the signals of the Pt-unsubstituted pyridine compound. These result s were explained in terms of the solvent effect. The chemical shifts d elta(C) and the coupling constants J(C-13-Pt-195) were measured and th e results interpreted with a view of obtaining information on the natu re of the Pt-N bond. The possibility of pi-bonding between platinum an d the pyridine ligand is examined. The conformation of the pyridine ri ng in relation to the platinum plane and the energies of the rotation barriers around the Pt-N bond in these types of platinum(II) complexes are briefly discussed. The crystal structure of trans-Pt(2,6-(HOCH2)( 2)py)(2)Cl-2 . 2H(2)O was determined by X-ray diffraction. The compoun d is monoclinic, C2/m, a = 7.022(6), b = 15.646(13), c = 8.344(10) Ang strom, beta = 93.35(8)degrees, Z = 2, R = 0.037. The platinum atom is located at the junction of the twofold axis and the mirror plane, the N atoms and the para-C atom of the pyridine ring are situated on the t wofold axis, and the chloride ligands are on the mirror plane. The com pound crystallizes with molecules of water, which are H-bonded to the hydroxy groups. The Pt-Cl bond distance is 2.306(2) Angstrom, and that of the Pt-N bond is 2.041(6) Angstrom. The dihedral angle between the platinum and the pyridine planes is 79.8 degrees.