Chiral Discrimination by Vibrational Spectroscopy Utilizing Local Modes

Authors

  • Elfi Kraka,

    Corresponding author
    1. Computational and Theoretical Chemistry Group, Department of Chemistry, Southern Methodist University, Dallas, TX
    • Correspondence to: Elfi Kraka, Computational and Theoretical Chemistry Group, Department of Chemistry, Southern Methodist University, 3215 Daniel Ave., Dallas, TX 75275–03114, USA. E-mail: ekraka@smu.edu

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  • Marek Freindorf,

    1. Computational and Theoretical Chemistry Group, Department of Chemistry, Southern Methodist University, Dallas, TX
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  • Dieter Cremer

    1. Computational and Theoretical Chemistry Group, Department of Chemistry, Southern Methodist University, Dallas, TX
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ABSTRACT

Chiral discrimination of homochiral and heterochiral H-bonded complexes is a challenge for both experimentalists and computational chemists. It is demonstrated that a two-pronged approach based on far-infrared vibrational spectroscopy and the calculation of local mode frequencies facilitates the chiral discrimination of H-bonded dimers. The local H-bond stretching frequencies identify the strongest H-bonds and by this the dominating chiral diastereomer. This is shown in the case of peroxide, trioxide, hydrazine, glycidol, and butan-2-ol dimers as well as propylene oxideglycidol complexes investigated with the help of second-order Møller–Plesset perturbation, coupled cluster, and density functional theory calculations where, in the latter case, the ωB97X-D functional was used for an improved description of H-bonding. In some cases, additional intermolecular interactions overrule the important role of H-bonding, which is found by calculating chirodiastaltic energies. Chirality 25:185–196, 2013. © 2013 Wiley Periodicals, Inc.

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