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Parallel Interactions at Large Horizontal Displacement in Pyridine–Pyridine and Benzene–Pyridine Dimers

Authors

  • Dragan B. Ninković,

    1. Innovation center of the Department of Chemistry, University of Belgrade, Studentski trg 12-16, 11000 Belgrade (Serbia)
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  • Jelena M. Andrić,

    1. Innovation center of the Department of Chemistry, University of Belgrade, Studentski trg 12-16, 11000 Belgrade (Serbia)
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  • Prof. Dr. Snežana D. Zarić

    Corresponding author
    1. Department of Chemistry, University of Belgrade, Studentski trg 12-16, 11000 Belgrade (Serbia), Fax: (+381) 11-2184-330
    2. Department of Chemistry, Texas A & M University at Qatar, P.O. Box 23874 Doha (Qatar)
    • Department of Chemistry, University of Belgrade, Studentski trg 12-16, 11000 Belgrade (Serbia), Fax: (+381) 11-2184-330
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Abstract

A study of crystal structures from the Cambridge Structural Database (CSD) and DFT calculations reveals that parallel pyridine–pyridine and benzene–pyridine interactions at large horizontal displacements (offsets) can be important, similar to parallel benzene–benzene interactions. In the crystal structures from the CSD preferred parallel pyridine–pyridine interactions were observed at a large horizontal displacement (4.0–6.0 Å) and not at an offset of 1.5 Å with the lowest calculated energy. The calculated interaction energies for pyridine–pyridine and benzene–pyridine dimers at a large offset (4.5 Å) are about 2.2 and 2.1 kcal mol−1, respectively. Substantial attraction at large offset values is a consequence of the balance between repulsion and dispersion. That is, dispersion at large offsets is reduced, however, repulsion is also reduced at large offsets, resulting in attractive interactions.

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