Chitosan with phosphonic and carboxylic group: New multidentate ligands

Abstract

Chemical modifications of polysaccharides are increasingly studied and they have potential providing new applications. N-methylene phosphonic N-methylene carboxylic chitosan was obtained in water soluble form using N-methylene phosphonic chitosan and glyoxylic acid (via aldimine formation) under reduction conditions with sodium borohydride. The modified chitosan was characterized by 1 H NMR, 13 C NMR and FTIR spectroscopy. A practical simple and safe preparative procedure has been established to obtain this novel water-soluble and filmogenic chitosan. Taking advantage of the introduction of multidentate ligands into chitosan macromolecule this derivative opens interesting perspectives including the posibility to chelate Ca(II) and others bivalent metals with technological and biomedical potential applications.