Interaction of 2-amino-, 3-amino-, and 4-aminopyridines with chromium and manganese ferrocyanides

The present investigation deals with the interaction of 2-aminopyridine, 3-aminopyridine, and 4-aminopyridine with chromium and manganese ferrocyanides. Chromium ferrocyanide possesses better adsorbing properties than manganese ferrocyanide. Maximum uptake was observed at neutral pH (pH 7.0). The adsorption data obtained at neutral pH are fitted in a Langmuir adsorption isotherm. The adsorption behavior of the aminopyridines studied follows the order 3-aminopyridine > 4-aminopyridine > 2-aminopyridine. The infrared spectral studies of adsorption adducts indicate that adsorption takes place through interactions between the adsorbate molecule and the outer divalent metal ion of metal ferrocyanides. From these studies, ii is clear that metal ferrocyanides and metal ions play a major role in the stabilization of organic molecules through their surface activity in the prebiotic environment. (C) 2000 Academic Press.