Complexes of 2-aminopyridine and its substituted derivatives with iodine

Depending on the amount of halogen used, 2-aminopyridine and its ring-substituted derivatives form complexes with 1 or 2 moles of iodine. In the presence of hydriodic acid, one equivalent of acid is included in the complex. 2-Amino-3,5-dibromopyridine forms a complex with 1 mole of iodine even in the presence of excess iodine or in the presence of HI. According to the IR spectra, the iodine in the complexes is coordinated with the ring nitrogen atom.