Nucleophilicity Index Based on Atomic Natural Orbitals

Table 2

Occupation numbers (11) and differences between the highest NO “energies” (15) in [kcal·moL⁻¹] for benzene and its derivatives, calculated within representation of “geometrically” orthogonalized atomic orbitals. For asymmetric species, the position refers to carbon atom with larger electron population. Methods: RHF/STO-3G, 6-31G*, and DFT/B3LYP/aug-cc-pVDZ.

Molecule	Position	STO-3G		6-31G*		Aug-cc-pVDZ
		𝑛𝑋^∗ℒ	Δ𝜀𝑋^∗ℒ	𝑛𝑋^∗ℒ	Δ𝜀𝑋^∗ℒ	𝑛𝑋^∗ℒ	Δ𝜀𝑋^∗ℒ
Fluorobenzene	ortho	1.039	−2.5	1.033	−8.2	0.786	−7.3
	meta	0.985	−7.3	0.958	−10.0	0.760	−7.5
	para	1.020	−1.3	1.013	−4.2	0.778	−3.7
Aniline	ortho	1.057	3.8	1.073	8.2	0.803	9.0
	meta	0.983	−1.4	0.949	−1.6	0.760	3.6
	para	1.035	6.7	1.047	10.4	0.794	11.0
Phenol	ortho	1.046	5.0	1.048	3.5	0.793	3.3
	meta	0.979	−3.7	0.949	−4.4	0.758	−0.9
	para	1.035	4.3	1.037	4.6	0.788	4.8
Nitrobenzene	ortho	0.971	−23.7	0.928	−27.2	0.738	−23.0
	meta	0.999	−19.6	0.992	−20.8	0.763	−19.1
	para	0.968	−20.5	0.930	−24.2	0.744	−20.6
Benzoic acid	ortho	0.974	−7.0	0.936	−12.2	0.737	−11.2
	meta	1.005	−6.3	0.999	−8.5	0.767	−9.0
	para	0.978	−7.5	0.940	−12.0	0.748	−10.9
Benzaldehyde	ortho	0.989	−6.7	0.954	−14.8	0.739	−14.5
	meta	1.004	−6.6	0.996	−10.9	0.768	−11.9
	para	0.984	−6.3	0.943	−13.1	0.746	−13.3