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Influence of Fluorination on the Conformational Properties and Hydrogen‐Bond Acidity of Benzyl Alcohol Derivatives
Author(s) -
Bogdan Elena,
Compain Guillaume,
Mtashobya Lewis,
Le Questel JeanYves,
Besseau François,
Galland Nicolas,
Linclau Bruno,
Graton Jérôme
Publication year - 2015
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201501171
Subject(s) - intramolecular force , chemistry , natural bond orbital , solvation , hydrogen bond , alcohol , computational chemistry , ab initio , fluorine , density functional theory , molecule , stereochemistry , organic chemistry
The effect of fluorination on the conformational and hydrogen‐bond (HB)‐donating properties of a series of benzyl alcohols has been investigated experimentally by IR spectroscopy and theoretically with quantum chemical methods (ab initio (MP2) and DFT (MPWB1K)). It was found that o ‐fluorination generally resulted in an increase in the HB acidity of the hydroxyl group, whereas a decrease was observed upon o , o′ ‐difluorination. Computational analysis showed that the conformational landscapes of the title compounds are strongly influenced by the presence of o ‐fluorine atoms. Intramolecular interaction descriptors based on AIM, NCI and NBO analyses reveal that, in addition to an intramolecular OH⋅⋅⋅F interaction, secondary CH⋅⋅⋅F and/or CH⋅⋅⋅O interactions also occur, contributing to the stabilisation of the various conformations, and influencing the overall HB properties of the alcohol group. The benzyl alcohol HB‐donating capacity trends are properly described by an electrostatic potential based descriptor calculated at the MPWB1K/6‐31+G(d,p) level of theory, provided solvation effects are taken into account for these flexible HB donors.