Phosphine–borane derivatives. 10. Vibrational spectra of the dimethylphosphine adducts of boron trihalides

Abstract

The infrared (200–4000 cm−1) and Raman (0–3100 cm−1) spectra of (CH3)2PHBX3, (CH3)2PDBX3, and (CD3)2PHBX3, where X = Cl, Br, I, have been recorded in solid state and in solutions at room temperature. The fundamentals have been assigned on the basis of Cs molecular symmetry. A modified Urey–Bradley force field model has been used in calculating the frequencies and potential energy distributions as well as the force constants. The (P—B) force constant was found to be consistent with the structural change upon adduct formation.

Predicting PH vibrations of gas phase molecules and surface‐adsorbed species using bond length‐frequency correlations

“…The largest deviations between theory and experiment are seen for the compounds containing multiple fluorines, though the deviations are still reasonable. In addition to the frequency shifts that have been measured in the gas phase, the frequency shifts for several of the dative bonded complexes of phosphines with boranes have been measured in the solid state (not listed) 46–49. The large positive values of the computed frequency shifts are consistent with the values derived from such solid state measurements.…”