The I.R. Spectra of Lysine Adsorbed on Several Cation-Substituted Montmorillonites

The i.r. spectra (4000-1200 cm-1) are obtained for several cation-substituted-montmonl-lonite-lysine complexes that were prepared at their natural pH’s. Analyses of the spectra of copper-, cobalt-, nickel- and zinc-montmorillonite films indicate that bidentate chelate complexes which contain protonated ∈-amino-groups are present in the interlamellar spaces. Investigation of the spectra of the hydrogen-, calcium- and natural-montmorillonite films indicates that the dominant adsorbed species for these complexes is a lysine cation in which both the α- and the ɛ-amino-groups are protonated while the carboxyl group is ionized.