Anion–π Interactions Involving [MXn]m Anions: A Comprehensive Theoretical Study

Authors

  • Carolina Estarellas,

    1. Department of Chemistry, Universitat de les Illes Balears, Crta. Valldemossa, km 7.5, Palma, 07122 (Spain), Fax: (+34) 971-173426
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  • Dr. David Quiñonero,

    1. Department of Chemistry, Universitat de les Illes Balears, Crta. Valldemossa, km 7.5, Palma, 07122 (Spain), Fax: (+34) 971-173426
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  • Prof. Dr. Pere M. Deyà,

    1. Department of Chemistry, Universitat de les Illes Balears, Crta. Valldemossa, km 7.5, Palma, 07122 (Spain), Fax: (+34) 971-173426
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  • Prof. Antonio Frontera

    Corresponding author
    1. Department of Chemistry, Universitat de les Illes Balears, Crta. Valldemossa, km 7.5, Palma, 07122 (Spain), Fax: (+34) 971-173426
    • Department of Chemistry, Universitat de les Illes Balears, Crta. Valldemossa, km 7.5, Palma, 07122 (Spain), Fax: (+34) 971-173426
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Abstract

In this manuscript we perform a systematic study on the geometric and energetic features of anion–π complexes, wherein the anion is a metal complex of variable shapes and charges. Such a study is lacking in the literature. For the calculations we used the ab initio RI-MP2/def2-TZVPP level of theory. A search in the Cambridge Structural Database (CSD) provides the experimental starting point that inspired the subsequent theoretical study. The influence of [MXn]m on the anion–π interaction was analyzed in terms of energetic, geometric, and charge transfer properties and Bader′s theory of “atom-in-molecules” (AIM). The binding energy depends on the coordination index, geometric features and different orientations adopted by the metallic anion. The binding mode resembling a stacking interaction for linear, trigonal planar and square-planar anions is the most favorable. For tetrahedral and octahedral anions the most favorable orientation is the one with three halogen atoms pointing to the ring.

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