Table 2.

Stacking energy (in kcal mol⁻¹) of substituted benzene-pyridine complexes (see Scheme 2), computed with various density functionals^a and MP2/6-31G*(0.25)^b

X=	MP2b	LDA	KT1	KT2	BHandH	PW91	BLYP	BP86	OLYP	B3LYP	X3LYP
H	−2.8	−3.4	−3.4	−3.2	−2.7	2.3	6.1	4.6	11.1	5.0	4.1
F	−2.9	−3.4	−3.3	−3.2	−2.8	2.5	6.4	4.9	11.5	5.1	4.2
NH2	−3.2	−3.6	−3.6	−3.3	−3.0	2.2	6.1	4.7	11.2	4.9	3.9
Cl	−3.4	−3.4	−3.4	−3.2	−2.8	2.6	6.7	5.1	11.9	5.4	4.4
CH3	−3.3	−3.3	−3.4	−3.2	−2.8	1.2	4.5	3.5	8.7	3.5	2.7
OH	−2.7	−3.2	−3.1	−3.0	−2.5	2.8	6.8	5.2	11.9	5.5	4.6
CN	−4.1	−3.9	−3.9	−3.7	−3.5	0.9	4.2	3.1	8.4	3.1	2.3
COOH	−3.5	−3.6	−3.6	−3.4	−3.0	2.4	6.4	4.8	11.5	5.1	4.2
CHO	−3.9	−3.8	−3.8	−3.6	−3.3	0.9	4.2	3.2	8.4	3.2	2.4
NO2	−3.8	−3.8	−3.7	−3.6	−3.3	2.0	5.8	4.3	10.8	4.6	3.7
MADc		0.26	0.25	0.24	0.39	5.33	9.07	7.68	13.90	7.89	6.99

^aPost-SCF on LDA/TZ2P orbitals and densities, see Computational details

^bFrom [50]

^cMean Absolute Deviation (in kcal mol⁻¹) of DFT energies from reference MP2 data