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

Ab initio quantum-mechanical investigations have been carried out to examin e the effects of substituents on structural deformations and electronic pro perties. We have studied eight substituent groups: two electron donor group s (-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 don or-acceptor combinations. As the donor strength increases from -NH2 to -N(C H3)(2), the change of the electronic properties shows the same trend for al l accepters. It has been shown that a constant like a Hammett constant exis ts and it can be used for the prediction of electronic properties. (C) 2000 Published by Elsevier Science B.V.