Synthesis of functional poly(amino acids) on cyclophosphazene templates

With the use of hexakis(p-aminophenoxy)cyclotriphosphazene and tetraphenyltetraaminocyclotetraphosphazene whose primary groups initiated the polymerization of L-α-alanine and γ-esters of L-α-glutamic acid n-carboxyanhydrides, poly(amino acids) containing an inorganic central ring have been prepared. Polypeptide chains of various lengths have been obtained by variation of the monomer-to-initiator molar ratio. The molecular masses of the synthesized samples are in good agreement with the calculated parameters, and the polymers show a narrow molecular-mass distribution (Mw/Mn < 1.3). The circular dichroism (CD) spectra and IR studies indicate a predominantly helical conformation of poly(amino acid) chains with the central triphosphazene ring and the disordered structure of poly(amino acid) chains bonded to cyclotetraphosphazene.