Hydrogen bonding in the gas phase. Part 1.—Infra-red spectroscopic investigation of amine–alcohol systems

Abstract

An infra-red investigation has been made of gas-phase hydrogen bonding between a range of amines and alcohols. Frequency displacements of the 0-H stretching vibration have been obtained for some thirty gas-phase hydrogen bonded complexes. These displacements for a se.ries of amines provide a measure of the relative electron donating abilities of the free arnineS : Et3N> Et2NHmMe3N > Me2NH > EtNHa > MeNH2 > NH3. Band contours for the 0-H stretching mode of such gas-phase complexes are reported and discussed. These can be interpreted in terms of sum-and-difference bands of the 0-H stretching vibration and the hydrogen bond stretching vibration. The interpretation can account for the qualitative changes in band contour that occur along a series of complexes. The systems considered include those formed by ammonia, methylamine, dimethy lamine, trimethylamine, ethylamine and diethy lamine with methanol, ethanol, isopropanol, t-butanol, and trifluoroethanol. Some complexes of triethylamine are also included. ' B. C. Stace and J. A. Stratford, to be published.

The effect of fluorine substitution in alcohol–amine complexes

“…Our observed fundamental OH-stretching wavenumbers agree with those previously observed for the alcohol-amine complexes. 13,[42][43][44] To determine the redshift of the OH-stretching vibration in the complexes relative to the alcohol monomers, spectra of the alcohols were recorded in the Dv OH = 1-3 region, and these also agree with previously recorded spectra ( Fig. 3 and Fig.…”

Investigations on 1-azabicycles. 26*. IR spectra of the simplest pyrrolizidine alcohols in the region of the stretching vibrations of the hydroxyl group and their connection with the stereochemistry of the compounds

“…In the gas phase base 3 has frequency band characteristics for the free and bonded hydroxyl higher than in CCl 4 solution (Table 1), which is in agreement with literature data for alcohols [29]. For the enthalpy of the IMHB in amino alcohol 3 in the gas phase ∆H = -17.6 ± 3.4 kJ·mol -1 , ∆S′ = -26.0 ± 6.5 J·K -1 ·mol -1 .…”

The crystal structure of perdeuterated methanol monoammoniate (CD3OD·ND3) determined from neutron powder diffraction data at 4.2 and 180 K

“…A 1:1 complex of CH 3 OH and NH 3 was identified in the gas phase by Millen & Zabicky (1962, 1965. This complex was subsequently studied experimentally using infrared spectroscopy (Hussein & Millen, 1974) and microwave spectroscopy (Fraser et al, 1988). The 1:1 methanol-ammonia complex has also been studied computationally using classical potentials (Brink & Glasser, 1982) and quantum mechanical methods (Li et al, 1997).…”