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Linclau B, Peron F, Bogdan E, Wells N, Wang Z, Compain G, Fontenelle CQ, Galland N, Le Questel JY, Graton J. Intramolecular OH⋅⋅⋅Fluorine Hydrogen Bonding in Saturated, Acyclic Fluorohydrins: The γ-Fluoropropanol Motif. Chemistry 2015; 21:17808-16. [PMID: 26494542 PMCID: PMC4676915 DOI: 10.1002/chem.201503253] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2015] [Indexed: 11/23/2022]
Abstract
Fluorination is commonly exercised in compound property optimization. However, the influence of fluorination on hydrogen-bond (HB) properties of adjacent functional groups, as well as the HB-accepting capacity of fluorine itself, is still not completely understood. Although the formation of OH⋅⋅⋅F intramolecular HBs (IMHBs) has been established for conformationally restricted fluorohydrins, such interaction in flexible compounds remained questionable. Herein is demonstrated for the first time-and in contrast to earlier reports-the occurrence of OH⋅⋅⋅F IMHBs in acyclic saturated γ-fluorohydrins, even for the parent 3-fluoropropan-1-ol. The relative stereochemistry is shown to have a crucial influence on the corresponding (h1) JOH⋅⋅⋅F values, as illustrated by syn- and anti-4-fluoropentan-2-ol (6.6 and 1.9 Hz). The magnitude of OH⋅⋅⋅F IMHBs and their strong dependence on the overall molecular conformational profile, fluorination motif, and alkyl substitution level, is rationalized by quantum chemical calculations. For a given alkyl chain, the "rule of shielding" applies to OH⋅⋅⋅F IMHB energies. Surprisingly, the predicted OH⋅⋅⋅F IMHB energies are only moderately weaker than these of the corresponding OH⋅⋅⋅OMe. These results provide new insights of the impact of fluorination of aliphatic alcohols, with attractive perspectives for rational drug design.
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Affiliation(s)
- Bruno Linclau
- Department of Chemistry, University of Southampton, Highfield, Southampton SO17 1BJ (UK), Fax: (+44) 23-8059-6805.
| | - Florent Peron
- Department of Chemistry, University of Southampton, Highfield, Southampton SO17 1BJ (UK), Fax: (+44) 23-8059-6805
| | - Elena Bogdan
- 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
| | - Neil Wells
- Department of Chemistry, University of Southampton, Highfield, Southampton SO17 1BJ (UK), Fax: (+44) 23-8059-6805
| | - Zhong Wang
- Department of Chemistry, University of Southampton, Highfield, Southampton SO17 1BJ (UK), Fax: (+44) 23-8059-6805
| | - Guillaume Compain
- Department of Chemistry, University of Southampton, Highfield, Southampton SO17 1BJ (UK), Fax: (+44) 23-8059-6805
| | - Clement Q Fontenelle
- Department of Chemistry, University of Southampton, Highfield, Southampton SO17 1BJ (UK), Fax: (+44) 23-8059-6805
| | - Nicolas Galland
- 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
| | - Jean-Yves Le Questel
- 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
| | - Jérôme Graton
- 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.
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Cormanich RA, Rittner R, Freitas MP, Bühl M. The seeming lack of CF⋯HO intramolecular hydrogen bonds in linear aliphatic fluoroalcohols in solution. Phys Chem Chem Phys 2014; 16:19212-7. [DOI: 10.1039/c4cp02463j] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Badawi HM, Ali SA. A study of the conformational stability and the vibrational spectra of 2,3-dichloro-1-propanol. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2010; 75:734-738. [PMID: 20022293 DOI: 10.1016/j.saa.2009.11.047] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2009] [Revised: 11/16/2009] [Accepted: 11/18/2009] [Indexed: 05/28/2023]
Abstract
The conformational stability and the three rotor internal rotations in 2,3-dichloro-1-propanol were investigated at DFT-B3LYP/6-311+G**, MP2/6-311+G** and MP4(SDQ) levels of theory. From the calculated potential energy surface, ten distinct minima were located all of which were predicted to have real frequencies at the B3LYP level of theory. The calculated lowest energy minima in the potential curves of the molecule were predicted to correspond to the Ggg and Gtg1 structures. The observed broad and very intense infrared band centered at about 3370 cm(-1) supports the existence of the strong intermolecular H-bonding in 2,3-dichloro-1-propanol. The equilibrium constants for the conformational interconversion in the molecule were estimated from the calculated Gibb's energies at the B3LYP/6-311+G** level of calculation and found to correspond to an equilibrium mixture of about 49% Ggg, 27% Gtg1, 5% Ggt and 5% Tgg conformations at 298.15K.
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Affiliation(s)
- Hassan M Badawi
- Department of Chemistry, King Fahd University of Petroleum & Minerals, Dhahran 31261, Saudi Arabia.
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Badawi HM, Förner W. Analysis of vibrational spectra of 3-halo-1-propanols CH(2)XCH(2)CH(2)OH (X is Cl and Br). SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2008; 71:1095-1101. [PMID: 18417416 DOI: 10.1016/j.saa.2008.03.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2008] [Accepted: 03/03/2008] [Indexed: 05/26/2023]
Abstract
The conformational stability and the three rotor internal rotations in 3-chloro- and 3-bromo-1-propanols were investigated by DFT-B3LYP/6-311+G and ab initio MP2/6-311+G, MP3/6-311+G and MP4(SDTQ)//MP3/6-311+G levels of theory. On the calculated potential energy surface twelve distinct minima were located all of which were not predicted to have imaginary frequencies at the B3LYP level of theory. The calculated lowest energy minimum in the potential curves of both molecules was predicted to correspond to the Gauche-gauche-trans (Ggt) conformer in excellent agreement with earlier microwave and electron diffraction results. The equilibrium constants for the conformational interconversion of the two 3-halo-1-propanols were calculated at the B3LYP/6-311+G level of calculation and found to correspond to an equilibrium mixture of about 32% Ggt, 18% Ggg1, 13% Tgt, 8% Tgg and 8% Gtt conformations for 3-chloro-1-propanol and 34% Ggt, 15% Tgt, 13% Ggg1, 9% Tgg and 7% Gtt conformations for 3-bromo-1-propanol at 298.15K. The nature of the high energy conformations was verified by carrying out solvent experiments using formamide ( epsilon=109.5) and MP3 and MP4//MP3 calculations. The vibrational frequencies of each molecule in its three most stable forms were computed at the B3LYP level and complete vibrational assignments were made based on normal coordinate calculations and comparison with experimental data of the molecules.
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Affiliation(s)
- Hassan M Badawi
- Department of Chemistry, King Fahd University of Petroleum and Minerals (KFUPM), Dhahran 31261, Saudi Arabia.
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