Synthesis and characterization of Pt(II) complexes with amine and carboxylato ligands. Crystal structure of (1,1-cyclobutanedicarboxylato)di(ethylamine)platinum(II)·H 2O

Abstract

Two methods for the synthesis of compounds of the type cis-PtA 2X 2 (A 2=bidentate amine or two monodentate amines and X 2=bidentate or two monodentate carboxylato ligands) were evaluated. The compounds were characterized by multinuclear NMR and IR spectroscopies. The 195Pt NMR chemical shifts were in the range −1615 to −1976 ppm, the higher field values corresponding to the complexes containing bidentate ligands. The coupling constants 3 J( 195Pt– 1H) are approximately 35 Hz, while the 2 J( 195Pt– 1HN) are about 70 Hz. One coupling constant 2 J( 195Pt– 13C) (53 Hz) was also measured. The crystal structure of the compound, cis-Pt(1,1-cyclobutanedicarboxylato)(C 2H 5NH 2) 2·H 2O belongs to the P2 1/ n space group with a=9.468(5), b=9.365(4), c=16.473(7) Å, β=105.08(3)°, Z=4 and R 1=0.0576. The PtN bond distances are 1.992(5) and 2.020(5) Å, while the PtO bonds are 2.000(4) and 2.015(4) Å. The molecules are held together by intermolecular H-bonds involving the lattice water molecules and the two free carbonyl O atoms and between the amino H atoms and the Pt-bonded CO groups.