Electrophilicity and nucleophilicity scales at different DFT computational levels

The reference electrophilicity and nucleophilicity scales established at the B3LYP/6-31G(d) level are herein extended by least squares regressions to the most common DFT computational methods used in theoretical organic chemistry studies, including B3LYP, MPWB1K, M062-X, and omega B97x-D, in combination with basis sets of the type 6-31G and 6-311G with different degrees of polarization and diffuse functions. Excellent linear correlations with coefficient of determination R-2 values between 0.97 and 1.00 are obtained. In this work, the new lower and upper threshold values of the scales are established at 48 DFT computational levels, which enables the direct classification and quantification of the electrophilic and nucleophilic character of molecules without necessarily relying upon the B3LYP/6-31G(d) scales. The present study shows that although the strong, moderate, or marginal thresholds of the electrophilicity and nucleophilicity scales can be modified up to a 24% (omega B97x-D/6-31G(d)) with the computational level, the relative position of the reagents on these scales does not change, allowing them to be used in the study of relative chemical reactivity.