“Recharging“ Group Electronegativities

Group electronegativity (gEN) is a fundamental concept of chemistry, relating to acidity, chemical reactivity, activating groups, and protecting groups. Although several empirical and computational methods have been devised for determining gEN, there is no straightforward computational method available to determine these values. We here revisit the determination of gENs using partial charges (“recharging”), computed at a high level of theory using the natural charge of a group (proton, methyl, vinyl, phenyl) bound to the substituent of interest and correlating the values with Pauling electronegativities. The results were found to be in good agreement with previous experimental and computational results. The values also qualitatively reproduced expected electronegativity trends. Furthermore, this work provides the first attempt to compare literature values by scaling them to a single metric (Pauling electronegativities). The method employed is simple and convenient, and could prove to be useful to chemists for determining the gEN of a substituent of interest, or by chemical educators as an assignment or laboratory exercise in a computational chemistry course.