Zur Elektronenstruktur metallorganischer Komplexe der f‐Elemente. 78[1]Ergänzende Informationen von “polarisierten” Raman‐Spektren orientierter Einkristalle und Modellrechnungen auf der Grundlage der Dichtefunktionaltheorie bei der Zuordnung der Schwingungsspektren von Decamethylosmocen

The far and mid infrared (FIR/MIR) spectra of powdered Os(?5-C5Me5)2 (OsCp*2) as well as the polarized Raman spectra of an oriented single crystal (where the two molecules of D5h symmetry in the unit cell are uniformly oriented) have been recorded. The latter allow the assignment of the observed Raman lines to irreducible representations (irreps) which agree well with the predictions of a calculation applying density functional theory. This finding suggests additional correlation of the observed (unpolarized) bands in the FIR/MIR spectra with the calculated wavenumbers (and their irreps) of IR active normal modes. Neglecting ?CH vibrations an r.m.s. deviation of 15.8 cm1 for 40 assignments (Raman and IR) could be achieved. Skeletal and intra-ligand vibrations could be identified and a number of previous assignments of the latter had to be revised. Because of mixing with skeletal modes some of the low frequency intra-ligand vibrations display a noticeable dependence on the mass of the central atom which prevents the direct transfer of the identified ?CCH3 and beta CCH3 normal modes from MCp*2 (M = Fe, Ru, Os) to LnCp*3 (Ln = La, Ce, Pr, Nd, Sm) complexes.