Adducts of NH₃ with the Conformers of Glycidol: A Rotational Spectroscopy Study

Abstract

Two locks accept the same master key: Two different complexes of ammonia with two different conformers of glycidol have been characterized by Fourier transform microwave spectroscopy (see picture; gray C, blue N, red O, white H). In both complexes NH3 is linked to the alcohol molecule through an OH⋅⋅⋅N (stronger) and an NH⋅⋅⋅O (weaker) hydrogen bond. Structural and energetic features of the hydrogen bonds are given.

Chirped‐Pulse and Cavity‐Based Fourier Transform Microwave Spectra of the Methyl Lactate⋅⋅⋅Ammonia Adduct

“…[10] (Please note that there is a typo for the sign of c zz for glycidol···NH 3 and NH 3 in Ref. [10].) In addition, a 14.5 % reduction in c zz upon complexation with ML was predicted theoretically, in good agreement with the experimental observation.…”

“…For example, the NH 3 internal rotation barrier is 2.438 kJ mol À1 for the most stable glycidol···NH 3 conformer. [10] This suggests that the strength of the NH···O = C Hbond in ML···NH 3 is very similar to that in the most stable conformer of glycidol···NH 3 . This similarity is also reflected in the corresponding moment-of-inertia values of the NH 3 top, which are related to the extent of the opening of the NH 3 Figure 1.…”

Chirality Recognition in the Glycidol⋅⋅⋅Propylene Oxide Complex: A Rotational Spectroscopic Study

“…This is the first high resolution study of a chiral contact pair with two different permanently chiral molecules. Only three high-resolution spectroscopic studies of Gly-containing complexes, that is, Gly···H 2 O, [13] Gly···Gly, [12] and Gly···NH 3 , [14] have been reported so far, and only one or two conformers were detected in each case. Gly has two major monomeric conformers, with one being about four times more abundant than the other at room temperature.…”

Weak hydrogen bonds in σ-1,4-difluorobenzene-ammonia: A rotational study

“…Indeed, in all the investigated systems where ammonia could play the double proton donor/acceptor role, F 3 CHÁ Á ÁNH 3 [7], CH 3 OHÁ Á ÁNH 3 [8], pyrroleÁ Á ÁNH 3 [9], tert-butanolÁ Á ÁNH 3 [10] and glycidolÁ Á ÁNH 3 [11], only the forms where NH 3 has a basic behavior have been observed.…”

“…In contrast with water, ammonia in its molecular complexes with organic or biomolecules, frequently acts preferably as a proton acceptor forming an intermolecular H-bond through the nitrogen lone pair [7][8][9][10][11]. Indeed, in all the investigated systems where ammonia could play the double proton donor/acceptor role, F 3 CHÁ Á ÁNH 3 [7], CH 3 OHÁ Á ÁNH 3 [8], pyrroleÁ Á ÁNH 3 [9], tert-butanolÁ Á ÁNH 3 [10] and glycidolÁ Á ÁNH 3 [11], only the forms where NH 3 has a basic behavior have been observed.…”