Kristallstrukturen, 195Pt-NMR-Verschiebungen, Schwingungsspektren und Normalkoordinatenanalysen von trans-Dihalogeno-bis(oxalato)platinaten(IV), trans-[PtX2(ox)2]2-, X = Cl, Br, I / Crystal Structure, 195Pt NMR Chemical Shifts, Vibrational Spectra, and Normal Coordinate Analyses of trans-Dihalogeno-bis(oxalato)platinates(IV), trans-[PtX2(ox)2]2-, X = Cl, Br, I

Abstract

By reaction of (n-Bu4N)2[Pt(ox)2] with elemental halogens in dichloromethane the complexes trans-[PtX2(ox)2]2- (X = Cl, Br, I) are formed. The crystal structures of trans-(py2CH2)[PtCl2(ox)2] · C4H6O3 (1) (monoclinic, space group P21/n, a = 12.119(3), b = 14.926(2), c = 12.666(4) Å, β = 91.26(3)°, Z = 4), trans-(py2CH2)[PtBr2(ox)2] (2) (monoclinic, space group P21/n, a = 7.402(8), b = 16.997(3), c = 14.898(3) Å, β = 98.15(3)°, Z = 4) and trans-(py2CH2)[PtI2(ox)2] ·C3H7NO (3) (orthorhombic, space group Pnma, a = 10.380(9), b = 13.973(2), c = 17.440(4) Å, Z = 4) have been determined by single crystal X-ray diffraction analysis. Highly resolution IR and Raman spectra were measured at low temperature (10 K). Using the molecular parameters of the X-ray determinations normal coordinate analyses based on a modified valence force field have been performed and the normal modes of vibration are assigned. The valence force constants are fd(PtCl) = 2.19, fd(PtBr) = 1.68, fd(PtI) = 1.28 mdyn/Å and fd(PtO) ranges from 2.71 to 2.82 mdyn/Å. The observed 195Pt NMR shifts are δ(195Pt) = 6472.4 (X = Cl), 6027.1 (Br) and 5142.7 ppm (I).