Synthesis and characterization of Pt(II) complexes with amine and carboxylato ligands. Crystal structure of (1,1-cyclobutanedicarboxylato)di(ethylamine)platinum(II)center dot H2O

Two methods for the synthesis of compounds of the type cis-PtA(2)X(2) (A(2) = bidentate amine or two monodentate amines and X-2 = bidentate or two mon odentate carboxylato ligands) were evaluated. The compounds were characteri zed by multinuclear NMR and IR spectroscopies. The Pt-195 NMR chemical shif ts were in the range -1615 to -1976 ppm, the higher field values correspond ing to the complexes containing bidentate ligands. The coupling constants ( 3)J(Pt-195-H-1) are approximately 35 Hz, while the (2)J(Pt-195-(HN)-H-1) ar e about 70 Hz. One coupling constant (2)J(Pt-195-C-13) (53 Hz) was also mea sured. The crystal structure of the compound, cis-Pt(1,1-cyclobutanedicarbo xylato)(C2H5NH2)(2). H2O belongs to the P2(1)/n space group with a = 9.468( 5), b = 9.365(4), c = 16.473(7) Angstrom, beta = 105.08(3)degrees, Z = 4 an d R-1 = 0.0576. The Pt-N bond distances are 1.992(5) and 2.020(5) Angstrom, while the Pt-O bonds are 2.000(4) and 2.015(4) Angstrom. The molecules are held together by intermolecular H-bonds involving the lattice water molecu les and the two free carbonyl O atoms and between the amino H atoms and the Pt-bonded C-O groups. (C) 2000 Elsevier Science S.A. All rights reserved.