Intermolecular Non-Covalent Carbon-Bonding Interactions with Methyl Groups: A CSD, PDB and DFT Study
A systematic evaluation of the CSD and the PDB in conjunction with DFT calculations reveal that non-covalent Carbon-bonding interactions with X−CH<sub>3</sub> can be weakly directional in the solid state (<i>P</i> ≤ 1.5) when X = N or O. This is comparable...
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| Format: | Article |
| Language: | English |
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MDPI AG
2019-09-01
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| Series: | Molecules |
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| Online Access: | https://www.mdpi.com/1420-3049/24/18/3370 |
| Summary: | A systematic evaluation of the CSD and the PDB in conjunction with DFT calculations reveal that non-covalent Carbon-bonding interactions with X−CH<sub>3</sub> can be weakly directional in the solid state (<i>P</i> ≤ 1.5) when X = N or O. This is comparable to very weak CH hydrogen bonding interactions and is in line with the weak interaction energies calculated (≤ −1.5 kcal·mol<sup>−1</sup>) of typical charge neutral adducts such as [Me<sub>3</sub>N-CH<sub>3</sub>···OH<sub>2</sub>] (<b>2a</b>). The interaction energy is enhanced to ≤−5 kcal·mol<sup>−1</sup> when X is more electron withdrawing such as in [O<sub>2</sub>N-CH<sub>3</sub>··O=C<sup>dme</sup>] (<b>20b</b>) and to ≤18 kcal·mol<sup>−1</sup> in cationic species like [Me<sub>3</sub>O<sup>+</sup>-CH<sub>3</sub>···OH<sub>2</sub>]<sup>+</sup> (<b>8a</b>). |
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| ISSN: | 1420-3049 |