Comparison of ESP values at the corresponding Ha atoms of model monomers VI-VIII (Fig. ), reveals the expected trend, i.e. the decrease of the ESP value in electron-rich 2,6-dimethylresorcinol VIII (+32 kJ mol -1 ) as compared to 1,3-dimethylbenzene VI (+43 kJ mol - 1 ), and substantial increase of the ESP in electron-deficient 1,3-dimethyl-2-nitrobenzene VII (+100 kJ mol -1 ). For IX (Fig. ), which contains two additional weakly electron donating methyl substituents, the ESP value at Ha decreases substantially (+82 kJ mol -1 ) as compared to VII (+100 kJ mol -1 ). Less expectedly, for X and XI, which contain stronger electron donating meta substituents (-OH or -OMe), the ESP values remain high (+97 kJ mol -1 for X and +92 kJ mol -1 for XI). Moreover, these values proved indifferent to the twist of the NO2 group (in X, the -NO2 group is coplanar with the aromatic ring, while in XI it is perpendicular). Instead, they depend on the rotation of OH/OMe groups (i.e. on torsion angle , Fig. ). The highest ESP values are reached for  = 0-30 in X and  = 0-100 in XI, and their angular dependences are similar to the trends observed for the dipole moments. These observations suggest that the positive potential at Ha originates mostly from the inductive effects of electronegative atoms (O and N) in the upper part of the ring. -OH and -OMe substituents in meta positions do not reduce the positive ESP significantly, which implies that these EDG substituents are not detrimental for CHanion interactions.