Amine–Halogen Charge-Transfer Interactions: Vibrational Spectra and Intramolecular Potentials

Abstract

Spectral data are presented for three acceptor complexes of trimethylamine and for two of their perdeuteroisotopes over the range 33–4000 cm⁻¹. Data were taken both at 300° and 83°K over the near‐infrared region. This has allowed a complete assignment of all intramolecular motions and the discovery of several of the weaker lattice intercombination frequencies. Data are reported in all three cases for low‐lying degenerate bending motions in the frequency range 33–80 cm⁻¹. The revised assignments reported here have permitted a complete description of the skeletal intramolecular potential which predicts properly the observed isotope effects. The model proposed suggests a revision of previous considerations regarding force fields in charge‐transfer complexes. In particular, it is necessary to account for skeletal stretch–bend interactions.