Formation of [C5H6(NH3)2]+ and [NH4(NH3)m]+ (m = 1–3) from size-selected aniline–ammonia cluster cations in intense laser fields

The fragmentation and intracluster chemical reaction processes of size-selected aniline–ammonia cluster cations [aniline(NH3)n]+ (n = 1–4) induced by intense femtosecond and nanosecond laser fields were investigated by tandem-type mass spectrometry. A new solute–solvent reaction to form [C5H6(NH3)2]+ was identified when the size of the cluster was increased to n = 4. On the basis of a quantum chemical calculation of the n = 4 cluster ion, it was inferred that one of the structural isomers of [aniline(NH3)4]+ is responsible for the chemical reaction through which a new type of strong intermolecular C–N bond is formed between the C5H6 moiety and one of the attached NH3 molecules.