ChemInform Abstract: THE STRUCTURE OF ANILINE

Abstract

Abstract The fully optimized equilibrium structure of aniline has been evaluated by Hartree—Fock gradient calculations using a 4–21 split valence shell basis set augmented by a set of d functions on the nitrogen atom. The optimization was repeated with two sets of d functions on nitrogen and single-point calculations have been made with d functions on all heavy atoms and with the latter set supplemented by a second set of polarization functions on nitrogen. Full geometry optimizations have also been made at the transition states for rotation and for inversion of the amine group. The small ring asymmetries deduced from analysis of the microwave spectrum are confirmed and compared with generalizations about variation of ring asymmetry with electronegativity of the substituent group. The angle between the amine group and the benzene ring is found to be approximately 52–55°, in contrast to the experimentally reported 37.6 ± 2.0°, and possible explanations for this major discrepancy are considered. Energy barriers for inversion and amine group rotation, dipole moments, and vertical ionization potentials are given.