Hydrogen bonding in organic compounds. IX. Intramolecular actions between the primary amine group and amino, nitro, sulphide, and sulphone groups in aromatic compounds

Spectroscopic evidence for the existence of intermolecular hydrogen bonds between aniline molecules has been obtained. Examples show the existence of intramolecular hydrogen bonds in orthodiamines, some amino-derivatives of heterocycles, 2-nitro-amines, 2-amino-sulphones, and 2-amino-sulphides. Some new observations, which do not agree with Krueger's interpretation of the profile of the overtone bands due to NH2 stretching vibrations, are recorded.