Vibrational spectra of phosphorus ligand derivatives of some alkyltricarbonyl-π-cyclopentadienylmolybdenum compounds

Raman and infrared spectra of a series of complexes RCOMo(CO)2[L]π-C5H5 (R = Me, Et, σ-C3H5, CH2Ph; L = PPh3, P(OCH2)3CCH3) and of ClMo(CO)2[PPh3]π-C5H5 and HW(CO)2[P(OPh)3]π-C5H5 have been recorded. In this complementary study of complex metal carbonyl compounds, assignments are suggested for metal–carbon–oxygen deformation, metal–carbon stretching, metal–ring, and metal–phosphorus stretching vibrations. It is thought that the latter occur in the range 240–200 cm−1, frequencies for phosphite complexes being lower than for the corresponding phosphine derivatives.