Aniline-ammonia complex, hydrogen bonds

The complex formation between ANI and ammonia clusters has been investigated by using mass resolved excitation spectroscopy (MRES), hole burning spectroscopy (HB)268 and IR spectroscopy coupled to different ionization spectroscopies269-271. Rotational spectra of these complexes are not reported yet. Some ab initio calculations on both neutral and ionized complexes are available269 272-274. In this case, the most stable form of the neutral ANI-NH3 complex is a consequence of a hydrogen bond between a NH bond of aniline... 

The N—H N hydrogen bond is responsible for the formation of the complexes between aniline and aliphatic amines (ammonia, methylamine, dimethylamine and tri-methylamine) which act as proton acceptors. Infrared photodissociation spectra and DFT calculation indicate208 that the clusters [aniline/ammonia]+ and [aniline/methylamine]+ have a non proton transferred (without the proton donation from the aniline moiety to the amine molecule) structure, while the complexes [aniline/dimethylamine]+, [aniline/ trimethylamine]+ possess a proton transferred structure. Reasonably, the proton transfer increases on increasing the proton affinity of the amine used as solvent. 

When chlorobenzene is treated with the strong base sodamide, Scheme 9.6 NaNH2, aniline is formed. This reaction is more complex than it appears, since if the chlorobenzene is labelled at C-l with the isotope l4C (indicated by an asterisk), then the product consists of equal amounts of aniline with the label at C-l and C-2. The reaction proceeds by abstraction .He-of the weakly acidic hydrogen atom on the carbon atom next to the ,l C-halogen group by the strong base, NH, followed by loss of halide ion. Ammonia then adds to the apparent triple bond of the resulting . . 

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