NMR AND X-RAY-DIFFRACTION STUDY OF THE CONFORMATIONAL STRUCTURE OF POLY[N(5)-(2-HYDROXYETHYL)-L-GLUTAMINE] AND XYETHYL)-L-GLUTAMINE-CO-GAMMA-L-GLUTAMYLHYDRAZIDE]

The conformation of poly[N5-(2-hydroxyethyl)-L-glutamine] (PHEG) and x yethyl)-L-glutamine-co-gamma-L-glutamylhydrazide] (P(HEG-GH)), in soli d state was studied by C-13 CP/MAS NMR spectrometry and X-ray diffract ion. The association of the copolymers in dichloroacetic acid was inve stigated by following the temperature dependence of their H-1 NMR spec tra. PHEG and P(HEG-GH)) were prepared by the reaction of poly(benzyl gamma-L-glutamate) with 2-aminoethanol and 2-aminoethanol-hydrazine mi xtures, respectively. The conformation of the copolymers depends on th e reaction conditions. While PHEG and the copolymers prepared with the mole ratio of hydrazine to the benzyl ester n(H)/n(B) = 0.25 were alm ost amorphous in solid state and had a random coil conformation and/or randomly oriented helices, at increased concentration of hydrazine (n (H)/n(B) = 0.5 and 1.0) P(HEG-GH) formed more or less ordered structur e characterized by assemblies of alpha-helices. The copolymers prepare d at n(H)/n(B) greater-than-or-equal-to 2.0 showed features of beta-sh eets. The tendency of the copolymers to form associates in Cl2CHCOOH s olution correlated well with their tendency to form ordered structures in solid state.