Electronic and vibrational spectra of aniline–benzene hetero-dimer and aniline homo-dimer ions

Structures of (aniline–benzene)+ and (aniline)2+ are re-investigated by electronic spectroscopy in the near-infrared region and vibrational spectroscopy in the NH stretching region. The spectra of (aniline–benzene)+ indicate a structure including a hydrogen bond between an NH bond of the ionic aniline and the π-electrons of the neutral benzene. Two isomers are suggested for (aniline)2+ in which an NH bond of the ionic aniline forms different types of hydrogen bond with the neutral aniline: one with the π-electrons of the aromatic ring and the other with the lone pair of the nitrogen atom.