Electronic structures of organometallic complexes of f elements LXXXII: Comparison of assigned experimental and calculated (on the basis of density functional theory) frequencies of normal vibrations of the first homoleptic organometallic complex of the l

• Polarized Raman spectra of an oriented organometallic single crystal.
• DFT calculations on normal modes of a pseudo-trigonal-planar lanthanide complex.
• Good agreement of experimental spectra and DFT predictions.

The far and mid infrared spectra of powdered La(η5-C5Me4H)3 as well as polarized Raman spectra of an oriented single crystal (where the principal axes of the two molecules per unit cell are uniformly oriented) have been recorded. Applying the selection rules of C3h symmetry to the experimental data, numerous signals were assigned which agree well with the predictions of a calculation based on density functional theory. Neglecting νC–H and γCp–H (out of plane) modes, an r.m.s. deviation of 21.9 cm−1 for 71 assignments was achieved. Skeletal and intra-ligand vibrations were separated and an inspection of the vibronic sidebands of the purely electronic hypersensitive absorption transitions 4I9/2 → 4G5/2 of Nd(η5-C5Me4H)3 showed that mainly the latter are coupled.

The results of density functional theory calculations on the frequencies and intensities of the vibrational spectra of La(η5-C5Me4H)3 are compared to the frequencies of IR (pellets) and Raman active normal modes (assigned on the basis of polarization measurements of oriented single crystals).Figure optionsDownload as PowerPoint slide