Elektronenspektren der Fluoro-Chloro-Osmate(V), [OsFnCl6–n]–, n = 0 — 6

Abstract

The electronic absorption spectra of the solid tetraethylammonium salts of [OsFnCl6-n]- are measured at 10 K. The strong bands in the UV/YIS region are assigned to charge transfer transitions from π(t1 u, t2 u) and σ(t1 u ) Cl orbitals into the π(t2g 3) Os(V) level. The weak intraconfigurational excitations within the t2g 3 manifold of Os(V) are split by spin-orbit coupling and lowered symmetry into Kramers doublets, observed in the range 5500-18000 cm-1. The 0 - 0-transitions are deduced from vibrational fine structure; for the centrosymmetric complexes they are confirmed by hot bands recorded in the normal temperature spectra. There is a systematical shift of all absorption bands to higher energy with increasing number of F-ligands.