Nucleophilicity Index Based on Atomic Natural Orbitals

Table 3

Occupation numbers (11) and differences between the highest NO “energies” (15) in [kcal·mol⁻¹] for benzene and its derivatives, calculated within representation of “physically” 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^∗𝒫	Δ𝜀𝑋^∗𝒫	𝑛𝑋^∗𝒫	Δ𝜀𝑋^∗𝒫	𝑛𝑋^∗𝒫	Δ𝜀𝑋^∗𝒫
Fluorobenzene	ortho	1.035	−2.8	1.059	−8.7	0.984	−6.2
	meta	0.981	−7.3	0.961	−9.9	0.984	−8.3
	para	1.018	−1.8	1.028	−5.3	1.000	−4.5
Aniline	ortho	1.053	5.6	1.100	5.5	1.033	6.7
	meta	0.978	−1.2	0.945	−1.1	0.989	2.2
	para	1.034	6.3	1.068	8.2	1.019	9.5
Phenol	ortho	1.041	4.5	1.068	2.2	1.014	3.8
	meta	0.975	−3.9	0.947	−4.7	0.983	−1.7
	para	1.033	3.8	1.056	3.5	1.016	4.3
Nitrobenzene	ortho	0.959	−23.6	0.900	−26.5	0.910	−21.5
	meta	0.998	−19.6	1.013	−21.1	0.992	−20.0
	para	0.963	−21.1	0.927	−25.5	0.945	−21.8
Benzoic acid	ortho	0.967	−7.3	0.920	−12.3	0.945	−11.3
	meta	1.007	−6.3	1.023	−8.6	0.997	−9.4
	para	0.976	−7.8	0.942	−12.8	0.955	−11.9
Benzaldehyde	ortho	0.986	−7.0	0.959	−15.0	0.959	−14.7
	meta	1.004	−6.5	1.016	−10.8	0.997	−12.2
	para	0.982	−6.6	0.947	−13.7	0.956	−14.0