Relationship between charge transfer and the structural deformation in para-substituted aniline derivatives

Ab initio quantum-mechanical investigations have been carried out to examine the effects of substituents on structural deformations and electronic properties. We have studied eight substituent groups: two electron donor groups (–NH2, –N(CH3)2) and six electron acceptor groups (–NO2, –BCl2, –BF2, –BH2, –CN, and –NC). These groups have been used to provide 12 different donor–acceptor combinations. As the donor strength increases from –NH2 to –N(CH3)2, the change of the electronic properties shows the same trend for all acceptors. It has been shown that a constant like a Hammett constant exists and it can be used for the prediction of electronic properties.