Infrared Study of 4- and 3-Substituted Anilines in Hexane,Carbon Tetrachloride,or Chloroform (0.5% or Less) Solutions

Abstract

As the NH₂ bond angle increases, both v_asym NH₂ and v_sym. NH₂ increase in frequency, and the frequency separation between v_asym. NH₂ and v_sym. NH₂ increases as the Hammett σ_p and σ_m values increase (increasing electron withdrawing power). The NH₂ bond angles change with solute/solvent interaction. In CHCl₃ solution IR bands are observed for two sets of v_asym. NH₂ and v_sym. NH₂ frequencies. It is suggested that this is the result of intermolecular hydrogen bonding between H₂N and HCCl₃ and between NH₂ and Cl(HCl₂)₂. In CCl₄ solution the intermolecular hydrogen bonding between the NH₂ protons and the Cl atoms of CCl₄ is stronger than between the Cl atoms of CHCl₃.