Molecules 2013, 18(6), 6829-6851; doi:10.3390/molecules18066829
Article

Exploring the C-X…π Halogen Bonding Motif: An Infrared and Raman Study of the Complexes of CF3X (X = Cl, Br and I) with the Aromatic Model Compounds Benzene and Toluene

Received: 23 April 2013; in revised form: 29 May 2013 / Accepted: 31 May 2013 / Published: 10 June 2013
(This article belongs to the Special Issue Halogen Bond: Application and Prospect)
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Abstract: The formation of halogen bonded complexes formed between the trifluorohalomethanes CF3Cl, CF3Br and CF3I and the Lewis bases benzene and toluene at temperatures below 150K was investigated using FTIR and Raman spectroscopy. Experiments using liquid krypton as solvent show that for both CF3Br and CF3I substantial fractions of the monomers can be involved in 1:1 complexes. In addition, weak absorptions illustrating the formation of 2:1 complexes between CF3I and benzene are observed. Using spectra recorded at temperatures between 120 and 140 K, observed information on the relative stability was obtained for all complexes by determining the complexation enthalpies in solution. The resulting values for CF3Br.benzene, CF3I.benzene and (CF3I)2.benzene are −6.5(3), −7.6(2) and −14.5(9) kJ mol−1. The values for CF3Br.toluene and CF3I.toluene are −6.2(5) and −7.4(5) kJ mol−1. The experimental complexation enthalpies are compared with theoretical data obtained by combining results from MP2/aug-cc-pVDZ(-PP) and MP2/aug-cc-pVTZ(-PP) ab initio calculations, from statistical thermodynamical calculations and from Monte Carlo Free Energy Perturbation simulations. The data are also compared with results derived for other C-X···π halogen bonded complexes involving unsaturated Lewis bases such as ethene and ethyne.
Keywords: halogen bonding; C-X···p interactions; infrared spectroscopy; Raman spectroscopy; cryosolutions
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MDPI and ACS Style

Nagels, N.; Hauchecorne, D.; Herrebout, W.A. Exploring the C-X…π Halogen Bonding Motif: An Infrared and Raman Study of the Complexes of CF3X (X = Cl, Br and I) with the Aromatic Model Compounds Benzene and Toluene. Molecules 2013, 18, 6829-6851.

AMA Style

Nagels N, Hauchecorne D, Herrebout WA. Exploring the C-X…π Halogen Bonding Motif: An Infrared and Raman Study of the Complexes of CF3X (X = Cl, Br and I) with the Aromatic Model Compounds Benzene and Toluene. Molecules. 2013; 18(6):6829-6851.

Chicago/Turabian Style

Nagels, Nick; Hauchecorne, Dieter; Herrebout, Wouter A. 2013. "Exploring the C-X…π Halogen Bonding Motif: An Infrared and Raman Study of the Complexes of CF3X (X = Cl, Br and I) with the Aromatic Model Compounds Benzene and Toluene." Molecules 18, no. 6: 6829-6851.

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