Collect. Czech. Chem. Commun. 1993, 58, 2415-2427

NMR and X-ray Diffraction Study of the Conformational Structure of Poly[N5-(2-hydroxyethyl)-L-glutamine] and Poly[N5-(2-hydroxyethyl)-L-glutamine-co-γ-L-glutamylhydrazide]

Drahomíra Hlavatá, Hana Pivcová, Jiří Spěváček, Dagmar Nosková and František Rypáček

Institute of Macromolecular Chemistry, Academy of Sciences of the Czech Republic, 162 06 Prague 6, Czech Republic


The conformation of poly[N5-(2-hydroxyethyl)L-glutamine] (P(HEG-GH)), in solid state was studied by 13C CP/MAS NMR spectrometry and X-ray diffraction. The association of copolymers in dichloroacetic acid was investigated by following the temperature dependence of their 1H NMR spectra, PHEG and P(HEG-GH) were prepared by the reaction of poly(benzyl γ-L-glutamate) with 2-aminoethanol and 2-aminoethanol-hydrazine mixtures, respectively. The conformation of the copolymers depends on the reaction conditions. While PHEG and the copolymers prepared with the mole ratio of hydrazine to the benzyl ester nH/nB = 0.25 were almost amorphous in solid state and had a random coil conformation and/or randomly oriented helices, at increased concentration of hydrazine (nH/nB = 0.5 and 1.0) P(HEG-GH) formed more or less ordered structure characterized by assemblies of α-helices. The copolymers prepared at nH/nB 3 2.0 showed features of β-sheets. The tendency of the copolymers to form associates in Cl2CHCOOH solutions correlated well with their tendency to form ordered structures in solid state.