| Autor: |
Goury, V., Jhurry, D., Bhaw-Luximon, A., Novak, B. M., Belleney, J. |
| Zdroj: |
Biomacromolecules; July 2005, Vol. 6 Issue: 4 p1987-1991, 5p |
| Abstrakt: |
The synthesis of random and block copolypolyeptides derived from γ-methylglutamate and leucine N-carboxyanhydrides using Al-Schiff's base complexes and allylamine as initiators is here reported. The copolymer structures were confirmed by 1H and 13C NMR. The calculation of the statistical average block lengths reveals the presence of longer methylglutamate units in the copolymer. The determination of the reactivity ratios indicated a slightly higher reactivity of γ-methylglutamateNCA as compared to leucineNCA. Block copolypeptides containing glutamate and leucine units were obtained by sequential polymerization of the two NCAs using Al-Schiff's base complexes or allylamine in dioxane as solvent. Based on 13C NMR spectra of copolymers exhibiting two signals corresponding to peptide linkages, we confirmed the block structure and concluded that the copolymerization proceeds by attack of an amino group present on a glutamate chain end onto a LeuNCA. The copolymerization with allylamine was also shown, from calculation of the average block lengths of sequences, to exhibit living behavior. Viscometry analysis further showed that molar masses of the copolypeptides obtained with Al-Schiff's base were quite close to those derived from allylamine, supporting the proposed mechanism of copolymerization. |
| Databáze: |
Supplemental Index |
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