Effects of Lewis Basicity and Acidity on σ-Hole Interactions in Carbon-Bearing Complexes: A Comparative Ab Initio Study
The effects of Lewis basicity and acidity on σ-hole interactions were investigated using two sets of carbon-containing complexes. In Set I, the effect of Lewis basicity was studied by substituting the X<sub>3</sub>/X atom(s) of the NC-C<sub>6</sub>H<sub>2</sub>-X&...
| Main Authors: | , , , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2022-10-01
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| Series: | International Journal of Molecular Sciences |
| Subjects: | |
| Online Access: | https://www.mdpi.com/1422-0067/23/21/13023 |
| Summary: | The effects of Lewis basicity and acidity on σ-hole interactions were investigated using two sets of carbon-containing complexes. In Set I, the effect of Lewis basicity was studied by substituting the X<sub>3</sub>/X atom(s) of the NC-C<sub>6</sub>H<sub>2</sub>-X<sub>3</sub> and NCX Lewis bases (LB) with F, Cl, Br, or I. In Set II, the W-C-F<sub>3</sub> and F-C-X<sub>3</sub> (where X and W = F, Cl, Br, and I) molecules were utilized as Lewis acid (LA) centers. Concerning the Lewis basicity effect, higher negative interaction energies (<i>E</i><sub>int</sub>) were observed for the F-C-F<sub>3</sub>∙∙∙NC-C<sub>6</sub>H<sub>2</sub>-X<sub>3</sub> complexes compared with the F-C-F<sub>3</sub>∙∙∙NCX analogs. Moreover, significant <i>E</i><sub>int</sub> was recorded for Set I complexes, along with decreasing the electron-withdrawing power of the X<sub>3</sub>/X atom(s). Among Set I complexes, the highest negative <i>E</i><sub>int</sub> was ascribed to the F-C-F<sub>3</sub>∙∙∙NC-C<sub>6</sub>H<sub>2</sub>-I<sub>3</sub> complex with a value of −1.23 kcal/mol. For Set II complexes, <i>E</i><sub>int</sub> values of F-C-X<sub>3</sub> bearing complexes were noted within the −1.05 to −2.08 kcal/mol scope, while they ranged from −0.82 to −1.20 kcal/mol for the W-C-F<sub>3</sub> analogs. However, <i>V</i><sub>s,max</sub> quantities exhibited higher values in the case of W-C-F<sub>3</sub> molecules compared with F-C-X<sub>3</sub>; preferable negative <i>E</i><sub>int</sub> were ascribed to the F-C-X<sub>3</sub> bearing complexes. These findings were delineated as a consequence of the promoted contributions of the X<sub>3</sub> substituents. Dispersion forces (<i>E</i><sub>disp</sub>) were identified as the dominant forces for these interactions. The obtained results provide a foundation for fields such as crystal engineering and supramolecular chemistry studies that focus on understanding the characteristics of carbon-bearing complexes. |
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| ISSN: | 1661-6596 1422-0067 |