title: Influence of Fluorination on the Conformational Properties and Hydrogen-Bond Acidity of Benzyl Alcohol Derivatives.
abstract: 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.
authors.affiliation: CEISAM UMR CNRS 6230, Faculté des Sciences et des Techniques, Université de Nantes 2, rue de la Houssinière, BP 92208, 44322 NANTES Cedex 3 (France), Fax: (+3) 2-51-12-54-02.
authors.forename: Elena
authors.initials: E
authors.lastname: Bogdan
authors.affiliation: Department of Chemistry, University of Southampton, Highfield, Southampton SO17 1BJ (UK), Fax: (+44) 23-8059-6805.
authors.forename: Guillaume
authors.initials: G
authors.lastname: Compain
authors.affiliation: Department of Chemistry, University of Southampton, Highfield, Southampton SO17 1BJ (UK), Fax: (+44) 23-8059-6805.
authors.forename: Lewis
authors.initials: L
authors.lastname: Mtashobya
authors.affiliation: CEISAM UMR CNRS 6230, Faculté des Sciences et des Techniques, Université de Nantes 2, rue de la Houssinière, BP 92208, 44322 NANTES Cedex 3 (France), Fax: (+3) 2-51-12-54-02.
authors.forename: Jean-Yves
authors.initials: JY
authors.lastname: Le Questel
authors.affiliation: CEISAM UMR CNRS 6230, Faculté des Sciences et des Techniques, Université de Nantes 2, rue de la Houssinière, BP 92208, 44322 NANTES Cedex 3 (France), Fax: (+3) 2-51-12-54-02.
authors.forename: François
authors.initials: F
authors.lastname: Besseau
authors.affiliation: CEISAM UMR CNRS 6230, Faculté des Sciences et des Techniques, Université de Nantes 2, rue de la Houssinière, BP 92208, 44322 NANTES Cedex 3 (France), Fax: (+3) 2-51-12-54-02.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Galland
authors.affiliation: Department of Chemistry, University of Southampton, Highfield, Southampton SO17 1BJ (UK), Fax: (+44) 23-8059-6805. bruno.linclau@soton.ac.uk.
authors.forename: Bruno
authors.initials: B
authors.lastname: Linclau
authors.affiliation: CEISAM UMR CNRS 6230, Faculté des Sciences et des Techniques, Université de Nantes 2, rue de la Houssinière, BP 92208, 44322 NANTES Cedex 3 (France), Fax: (+3) 2-51-12-54-02. jerome.graton@univ-nantes.fr.
authors.forename: Jérôme
authors.initials: J
authors.lastname: Graton
keywords: benzylic alcohols; conformation analysis; fluorine; hydrogen-bond acidity