Aniline cation intermolecular hydrogen bonds

D. Intermolecular Hydrogen Bonds of Aniline Cation Infrared Depletion... 

The NH2 stretching mode of the complex between aniline and furan and its cation indicates193 that the main intermolecular interaction is due to a weak hydrogen bond of the N—H group and the oxygen of furan as depicted in 120. On the contrary, for the aniline furan cation complex 121 the main interaction is between the N—H group and the n system of the furan ring. 

The dependence of organic base adsorption on pH is illustrated by the case of benzidine. This base is adsorbed from aqueous solutions on Ca- and Na-montmorillonite as a mixture of monovalent and divalent cations at pH 3 and as neutral molecules when the pH is higher. Aniline is also adsorbed as a mixture of monovalent cations and neutral molecules at pH = 3.2. Amounts adsorbed are in excess of the exchange capacity of the clay, and in both cases intermolecular association by hydrogen bonds (see Fig. 1) is assumed to exist between cations and molecules in the interlayer space (23). 

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