Intermolecular H‐bond in propan‐2‐ol and its solutions with acetonitrile

Abstract

Formation of propan-2-ol-acetonitrile dimers is manifested in the Raman spectra as an appearance of a band of aggregates in the high-wavenumber side of the C N vibrational band of liquid acetonitrile (∼2 cm −1 ). The intensity of the band of aggregates changes with a change in the concentration of the mixture (1-0.05 mole fraction).For propan-2-ol we carried out nonempirical calculations of a structure of isolated dimer aggregates. The formation of an intramolecular H-bond between the H and the O atom of the HCO H group of length 2.045Å is possible in the monomer molecule. The CH 3 groups of alcohol are not equivalent. In the dimer formation, intramolecular H-bond in the HCO H group is preserved. An intermolecular H-bond of length 2.045Å and energy 15 kJ/mole is formed between the H atom of one molecule and the O atom of another molecule of the O-H. The length and energy of the H-bond for the propan-2-ol-acetonitriledimer formations calculate to 2.27Å and 12.9 kJ/mole, respectively. The H-bond is formed by s-electrons of nitrogen. The experimental data and the results of calculations are in good agreement.

Raman Spectra and Intermolecular Hydrogen Bonds of Quinoline in Solutions

“…Any complexity similar to that in the case of pyridine-propan-2-ol solutions [48] is not manifested for the 1040-cm −1 band of aggregates. In [49], it was shown that the participation of molecules of propan-2-ol in the formation of H-aggregates is evident not only in the band of O-H vibrations, but also in the bands of vibrations of atoms, which are not directly involved in the formation of intermolecular hydrogen bonds. In particular, the 820-cm −1 band of propan-2-ol involved in the formation of H-bonds in the process of self-association or with proton-donor molecules is appeared to be of doublet character.…”

Recent advances in linear and nonlinear Raman spectroscopy II

“…152 This Raman study is of particular interest to the scientific community due to the biological importance of formamide and the general interest in donor-acceptor reactions which are central to a wide range of chemical activities. In a further work, Tukhvatullin et al 153 studied the intermolecular H-bond in propan-2-ol and its solutions with acetonitrile. Hydrogen bonding and motional narrowing in binary mixtures of 2-and 3-bromopyridine in methanol, probed by polarized Raman scattering and DFT calculations, were the subject of a work published by Ojha et al 154 The same research group 155 performed a concentration-dependent Raman study of the noncoincidence effect in the NH 2 bending and C O stretching modes of HCONH 2 in the binary mixture (HCONH 2 C CH 3 OH).…”