Interaction of 2-amino, 3-amino and 4-aminopyridines with nickel and cobalt ferrocyanides

The present investigations deal with the interaction of 2-aminopyridine (2AP), 3-aminopyridine (3AP) and 4-aminopyridine (4AP) with nickel ferrocyanide (NiFc) and cobalt ferrocyanide (CoFc). Nickel ferrocyanide is found to be a better adsorbent. Maximum uptake was observed at neutral pH (pH, 7.0). The adsorption data obtained at neutral pH is fitted in Langmuir adsorption isotherm. The adsorption behavior of studied aminopyridines followed the order: 3-aminopyridine>4-aminopyridine>2-aminopyridine. The infrared spectral studies of adsorption adducts indicate that adsorption takes place through interaction between adsorbate molecule and outer divalent metal ion of metal ferrocyanides. From these studies, it is clear that metal ferrocyanides and metal ions play major role in stabilisation of aminopyridines through their surface activity in prebiotic environment.