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 vasym NH2 and vsym. NH2 increase in frequency, and the frequency separation between vasym. NH2 and vsym. NH2 increases as the Hammett σp and σm 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 vasym. NH2 and vsym. 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.