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A heteronuclear (Pt, Zn) complex of 1-methyluracil with different coordination geometries (square-planar and square-pyramidal) of the two metals

1985; Elsevier BV; Volume: 108; Issue: 2 Linguagem: Inglês

10.1016/s0020-1693(00)81616-3

1873-3255

Helmut Schóllhorn, Ulf Thewalt, Bernhard Lippert,

Crystal structures of chemical compounds

Reaction of cis-(NH3)2Pt(1-MeU)2 (1-MeU = 1- methyluracil anion, C5H5N2O2) with ZnSO4·7H2O leads to the formation of a dinuclear complex of composition [(NH3)2Pt(C5H5N2O2)2Zn(H2O)3]SO4· 2H2O. The compound crystallizes in space group P21/c with a = 10.534(1), b = 17.933(2), c = 11.490(1) Å, β=94.61(1)°, Z=4. The structure was refined to R=0.043 and Rw=0.061. In this compound, Pt is coordinated through N3 to the 1-MeU ligand, while Zn is bound through the two O4 oxygens and completes its distorted square-pyramidal coordination sphere by three aqua ligands. The positions of the two metals relative to their basal donor atoms and the shortness of the PtZn separation (2.760(1) Å) suggest a bonding interaction between the two metals. Using 1H NMR spectroscopy, a formation constant of ca. 114 1 mol−1 for the Pt, Zn complex has been estimated.