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

From: π-π stacking tackled with density functional theory

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
MAD c   0.26 0.25 0.24 0.39 5.33 9.07 7.68 13.90 7.89 6.99
  1. aPost-SCF on LDA/TZ2P orbitals and densities, see Computational details
  2. bFrom [50]
  3. cMean Absolute Deviation (in kcal mol−1) of DFT energies from reference MP2 data