Is there a trend in inductive effect for different alkyl groups?
Mark C Elliott1, Colan E Hughes1, Peter J Knowles1
1School of Chemistry, Cardiff University Park Place Cardiff CF10 3AT UK elliottmc@cardiff.ac.uk.
This study found no significant difference in the inductive effects of common alkyl groups using Hirshfeld charge analysis. Alkyl group electronegativity did not correlate with electron-donating or withdrawing abilities, suggesting Hirshfeld charges are more reliable for charge distribution analysis.
Area of Science:
- Computational chemistry
- Organic chemistry
Background:
- Understanding the electronic effects of alkyl groups is crucial in organic chemistry.
- Traditional methods like electronegativity may not accurately reflect charge distribution.
Purpose of the Study:
- To compare the inductive effects of four representative alkyl groups.
- To evaluate the correlation between alkyl group properties and their electronic influence.
- To determine the reliability of Hirshfeld charge analysis versus other methods for assessing charge distribution.
Main Methods:
- Hirshfeld charge analysis was employed to quantify charge distribution.
- Calculated charges were compared across different alkyl groups.
- Alkyl group electronegativity values were assessed for correlation.
Main Results:
- No significant differences were observed in the inductive effects of the studied alkyl groups via Hirshfeld analysis.
- Alkyl group electronegativity showed a poor correlation with electron-donating/withdrawing abilities.
- A significant divergence was noted between 13C NMR chemical shifts and calculated Hirshfeld charges.
Conclusions:
- Hirshfeld charge analysis provides a more reliable measure of charge distribution than alkyl group electronegativity.
- 13C NMR chemical shifts may not directly reflect the electronic effects indicated by Hirshfeld charges.
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