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Wilson CG, Plesniar J, Kuhn H, Armstrong J, Wood PA, Parsons S. The Advantages of Flexibility: The Role of Entropy in Crystal Structures Containing C-H···F Interactions. CRYSTAL GROWTH & DESIGN 2024; 24:2217-2225. [PMID: 38463616 PMCID: PMC10921377 DOI: 10.1021/acs.cgd.4c00042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/11/2024] [Revised: 02/09/2024] [Accepted: 02/09/2024] [Indexed: 03/12/2024]
Abstract
Molecular crystal structures are often interpreted in terms of strong, structure directing, intermolecular interactions, especially those with distinct geometric signatures such as H-bonds or π-stacking interactions. Other interactions can be overlooked, perhaps because they are weak or lack a characteristic geometry. We show that although the cumulative effect of weak interactions is significant, their deformability also leads to occupation of low energy vibrational energy levels, which provides an additional stabilizing entropic contribution. The entropies of five fluorobenzene derivatives have been calculated by periodic DFT calculations to assess the entropic influence of C-H···F interactions in stabilizing their crystal structures. Calculations reproduce inelastic neutron scattering data and experimental entropies from heat capacity measurements. C-H···F contacts are shown to have force constants which are around half of those of more familiar interactions such as hydrogen bonds, halogen bonds, and C-H···π interactions. This feature, in combination with the relatively high mass of F, means that the lowest energy vibrations in crystalline fluorobenzenes are dominated by C-H···F contributions. C-H···F contacts occur much more frequently than would be expected from their enthalpic contributions alone, but at 150 K, the stabilizing contribution of entropy provides, at -10 to -15 kJ mol-1, a similar level of stabilization to the N-H···N hydrogen bond in ammonia and O-H···O hydrogen bond in water.
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Affiliation(s)
- Cameron
J. G. Wilson
- Centre
for Science at Extreme Conditions, School of Chemistry, The University of Edinburgh, King’s Buildings, West Mains
Road, Edinburgh EH9 3FJ, U.K.
| | - Jan Plesniar
- Centre
for Science at Extreme Conditions, School of Chemistry, The University of Edinburgh, King’s Buildings, West Mains
Road, Edinburgh EH9 3FJ, U.K.
| | - Heike Kuhn
- Centre
for Science at Extreme Conditions, School of Chemistry, The University of Edinburgh, King’s Buildings, West Mains
Road, Edinburgh EH9 3FJ, U.K.
| | - Jeff Armstrong
- ISIS
Facility, STFC, Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire OX11 0QX, U.K.
| | - Peter A. Wood
- The
Cambridge Crystallographic Data Centre, 12 Union Road, Cambridge CB2 1EZ, U.K.
| | - Simon Parsons
- Centre
for Science at Extreme Conditions, School of Chemistry, The University of Edinburgh, King’s Buildings, West Mains
Road, Edinburgh EH9 3FJ, U.K.
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Ruivo D, Pereiro AB, Esperança JMSS, Canongia Lopes JN, Rebelo LPN. Rationalizing the Diverse Solid−Liquid Equilibria of Binary Mixtures of Benzene and Its Fluorinated Derivatives. J Phys Chem B 2010; 114:12589-96. [DOI: 10.1021/jp105639p] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Diana Ruivo
- Instituto de Tecnologia Química e Biológica, (www.itqb.unl.pt), UNL, Av. República, Apartado 127, 2780-901 Oeiras, Portugal, Chemical Engineering Department, Vigo University, P.O. Box 36310, Vigo, Spain, and Centro de Química Estrutural, (cqe.ist.utl.pt), IST/UTL, 1049 001 Lisboa, Portugal
| | - Ana B. Pereiro
- Instituto de Tecnologia Química e Biológica, (www.itqb.unl.pt), UNL, Av. República, Apartado 127, 2780-901 Oeiras, Portugal, Chemical Engineering Department, Vigo University, P.O. Box 36310, Vigo, Spain, and Centro de Química Estrutural, (cqe.ist.utl.pt), IST/UTL, 1049 001 Lisboa, Portugal
| | - José M. S. S. Esperança
- Instituto de Tecnologia Química e Biológica, (www.itqb.unl.pt), UNL, Av. República, Apartado 127, 2780-901 Oeiras, Portugal, Chemical Engineering Department, Vigo University, P.O. Box 36310, Vigo, Spain, and Centro de Química Estrutural, (cqe.ist.utl.pt), IST/UTL, 1049 001 Lisboa, Portugal
| | - José N. Canongia Lopes
- Instituto de Tecnologia Química e Biológica, (www.itqb.unl.pt), UNL, Av. República, Apartado 127, 2780-901 Oeiras, Portugal, Chemical Engineering Department, Vigo University, P.O. Box 36310, Vigo, Spain, and Centro de Química Estrutural, (cqe.ist.utl.pt), IST/UTL, 1049 001 Lisboa, Portugal
| | - Luis P. N. Rebelo
- Instituto de Tecnologia Química e Biológica, (www.itqb.unl.pt), UNL, Av. República, Apartado 127, 2780-901 Oeiras, Portugal, Chemical Engineering Department, Vigo University, P.O. Box 36310, Vigo, Spain, and Centro de Química Estrutural, (cqe.ist.utl.pt), IST/UTL, 1049 001 Lisboa, Portugal
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