An ab initio study of atomic interactions in monosubstituted benzenes

Molecules of monosubstituted benzenes XC₆H₅ (X = F, Cl, Br, OH, NH₂, CH₃, CH₂CH₃) were studied by the RHF/6-311G(d) method with full geometry optimization. Analysis of the molecular orbitals and contributions made to them by atomic orbitals, and also of the populations of the valence p orbitals of atoms in substituents X directly bonded to the aromatic ring showed that the features of the electron distribution in such molecules should not be attributed to the capability of the lone electron pairs of the heteroatoms in these substituents for p,π conjugation with the π-electron system of the molecule.