Complexes of A-H Acids with Triethylamine: Specificities of Spectroscopic Characteristics

Abstract

Abstract According to the donor-acceptor model of hydrogen bonding, the intermolecular bonds R-AH…BR1 and R-A−…H+BR1 are, in the main, of the same nature1. In this case, the charge transfer at acid-base interaction causes the existence of H-complexes I and II and the majority of their properties. For one thing, this determines the significant changes in the intensity (A) stretching vibration ν (AH) in the IR-spectra and in the proton chemical shift (δH) in the PMR spectra. In view of this, the study of changes in the magnitudes of A and δH, when the acid-base properties of the molecules interacting in the reaction (1) vary widely, presents significant interest. This allows not only to elucidate more fully the reasons causing changes in the values A and δH, but to establish their bonds with the structure of forming H-complexes and the enthalpy of their formation (−ΔH), which for (1) changes from ∼1 t o 40 kcal/mole2.