ELECTRON-STRUCTURE OF ORGANOMETAL COMPLEXES OF F-ELEMENTS .29. OPTICAL AND MAGNETOCHEMICAL ANALYSIS OF MONOACETONITRILE AND BIS-ACETONITRILE ADDUCTS OF THE TRIS-(ETA-5-CYCLOPENTADIENYL)PRASEODYMIUM(III)

The results of absorption, emission and magnetochemical measurements for mono and bisacetonitrile adducts derived from tris(eta-5-cyclopentadienyl)praseodymium(III) are reported. On the basis of these measurements the truncated crystal field splitting pattern of CP3Pr.NCCH3 could be derived. The absorption and luminescence spectra of CP3Pr(NCCH3), however, lead to two different splitting patterns. The parameters of an empirical Hamiltonian were fitted to the experimentally derived splitting patterns. In order to favour one of the two alternative parameter sets for CP3Pr(NCCH3)2, model calculations adopting the angular overlap model have been performed. Additionally, from the eigenvectors and eigenvalues obtained from the alternative fits, the temperature dependence of the paramagnetic susceptibility was calculated and compared with experimental data.