Attraction between electrophilic caps: A counterintuitive case of noncovalent interactions |
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Authors: | Changwei Wang David Danovich Sason Shaik Wei Wu Yirong Mo |
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Institution: | 1. Institute of Chemistry, The Hebrew University, Jerusalem, 91904 Israel;2. Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry and State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 360015 China;3. Department of Chemistry, Western Michigan University, Kalamazoo, Michigan, 49008 |
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Abstract: | Intermolecular attractive interaction between electrophilic sites is a counterintuitive phenomenon, as the electrostatic interaction therein is repulsive and destabilizing. Here, we confirm this phenomenon in four representative complexes, using state-of-the-art quantum mechanical methods. By employing the block-localized wavefunction (BLW) method, which can turn off intermolecular charge transfer interactions, we profoundly demonstrated the significance of charge transfer interactions in these seemingly counterintuitive complexes. Indeed, after being “turned off” the intermolecular charge transfer interaction in, for example, the FNSi···BrF complex, the originally attractive intermolecular interaction turns to be repulsive. The energy decomposition approach based on the BLW method (BLW-ED) can partition the overall stability gained on the formation of intermolecular noncovalent interaction into several physically meaningful components. According to the BLW-ED analysis, the electrostatic repulsion in these counterintuitive cases is overwhelmed by the stabilizing polarization, dispersion interaction, and most importantly, the charge transfer interaction, resulting in the eventual counterintuitive overall attraction. The present study suggests that, predicting bonding sites of noncovalent interactions using only the “hole” concept may be not universally sufficient, because other significant stabilizing factors will contribute to the stability and sometimes, play even bigger roles than the electrostatic interaction and consequently govern the complex structures. © 2018 Wiley Periodicals, Inc. |
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Keywords: | noncovalent interaction electrostatic attraction σ-hole energy decomposition analysis valence bond theory |
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