Nonparameterized (Fenske-Hall)-type molecular orbital calculations have been performed on several d0, d1, and d2 M(IV) M(η5-C5H5)2L2molecules, and the results have been found to be completely compatible with the interpretations obtained from the electron paramagnetic resonance and photoelectron spectral measurements as well as from the crystallographically acquired bond-length and bond-angle data. The MO calculations reveal that the LUMO for the d0Ti(IV) complexes and the HOMO for the d1and nonhydridic d2M(IV) complexes possess analogous orbital characters principally associated with the metal dz2and dx2-y2AO's with considerable contributions from the 3p AO's of the sulfur or chlorine L ligands. The relative metal orbital compositions of the HOMO's in the open-shell d1V(IV) complexes are in remarkable agreement with those obtained from our previously reported dilute single-crystal EPR studies on V(η5-C5H5)S5and V(η-C5H4CH3)Cl2. For V(η5-C5H5)S5the per cent character ratio of 3dz2/3dx2-y2= 12.7/1 (EPR) vs. 7.7/1 (MO), while the corresponding ratio of 20.0/1 from the EPR data on V(η-C5H4CH3)Cl2compares with that of 20.5/1 from the MO computations. Additional information concerning the electronic structure of M(η5-C5H5)2L2complexes has been obtained from photoelectron spectroscopy. The PE spectra of M(η5-C5H5)2Cl2and M(η-C5H4CH3)2Cl2(where M = Ti, V) are presented and interpreted with the aid of the approximate MO calculations.
ASJC Scopus subject areas
- Colloid and Surface Chemistry