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Ab initio conformational studies on diols and binary diol‐water systems using DFT methods. Intramolecular hydrogen bonding and 1:1 complex formation with water
Author(s) -
Klein Roger A.
Publication year - 2002
Publication title -
journal of computational chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.907
H-Index - 188
eISSN - 1096-987X
pISSN - 0192-8651
DOI - 10.1002/jcc.10053
Subject(s) - intramolecular force , diol , ab initio , chemistry , hydrogen bond , butane , propane , computational chemistry , density functional theory , ab initio quantum chemistry methods , hydrogen , crystallography , stereochemistry , molecule , organic chemistry , catalysis
Abstract Studies on the conformational equilibrium for the following diols, ethane‐1,2‐diol (12EG, CAS 107‐21‐1), 2R‐D‐(−)‐propane‐1,2‐diol (12PG, CAS 4254‐14‐2), (2S,3S)‐L‐(+)‐butane‐2,3‐diol (L23BD, CAS 19132‐06‐0), and (2S,3R)‐ meso ‐butane‐2,3‐diol (m23BD, CAS 5341‐95‐7), are described using Gaussian ab initio calculations involving density functional theory (DFT) methods. We also report in this article results on the stability and conformation for the 1:1 water‐diol complex formed by ethane‐1,2‐diol, propane‐1,2‐diol, and L‐ and meso ‐butane‐2,3‐diol. The relative stability of the intramolecular (internal) hydrogen bond in a range of diols ( n = 2 to 6), based on ab initio geometry optimization and determination of the O…H distance, d OH , and OH…O angle, θ, increases through the sequence 1,2 ≈ 2,3 < 1,3 < 1,4 ≈ 1,5 ≈ 1,6, as judged from the bond linearity and O…H separation. Quantum mechanical and topological analysis of possible intramolecular hydrogen bonding in this complete series of diols provides convincing evidence for this in diols in which the hydroxyl groups are separated by three or more carbon atoms, that is, in ( n , n + m ) diols for m ≥ 2, but not for ethane‐1,2‐diol or other vicinal diols, which do not satisfy Popelier's topological and electron density criteria based on the AIM theory of Bader. Based on these criteria it is unlikely that vicinal diols are in fact capable of forming an intramolecular hydrogen bond, in spite of geometric and spectroscopic data in the literature suggesting otherwise. © 2002 Wiley Periodicals, Inc. J Comput Chem 23: 585–599, 2002