Schwingungsspektren und Normalkoordinatenanalyse der 35Cl/37Cl-isotopierten Chloro-Iodo-Osmate(IV), [OsClnI6-n]2-, n = 0-6 / Vibrational Spectra and Normal Coordinate Analysis of the 35Cl/37Cl Labelled Chloro-Iodo-Osmates(IV), [OsClnI6-n]2-, n = 0-6

Abstract

All components of the two series [Os35ClnI6-n]2- and [Os37ClnI6-n]2-, n = 0-6, including the pairs of geometric isomers for n = 2, 3, 4, have been prepared and isolated by ion exchange chromatography on DEAE cellulose. The highly resolved low temperature (80 K) IR and Raman spectra of the pure isotopomers show distinct isotopic shifts for different vibrational modes up to 10 cm-1. Normal coordinate analyses have been performed, based on a general valence force field. Due to the stronger trans influence of I as compared to Cl in all asymmetric Cl˙—Os—I′ axes the Os—I′ bonds are strengthened and the Os—Cl˙ bonds are weakened, as indicated by valence force constants for Os—I′ approximately 9% higher, for Os—Cl˙ 7% lower, as compared with the values calculated for symmetric axes.