Copolymerization of sarcosine-NCA and l-leucine-NCA or l-phenylalanine-NCA

Autor:	Kai-Uwe Tönnes, Hans R. Kricheldorf
Rok vydání:	1991
Předmět:	Sarcosine Polymers and Plastics Organic Chemistry Nuclear magnetic resonance spectroscopy respiratory system Carbon-13 NMR Condensed Matter Physics Sodium methoxide chemistry.chemical_compound Benzylamine chemistry Pyridine Polymer chemistry Materials Chemistry Reactivity (chemistry) Triethylamine
Zdroj:	Makromolekulare Chemie. Macromolecular Symposia. :313-328
ISSN:	0258-0322
DOI:	10.1002/masy.19910420126
Popis:	Copolymerizations of sarcosine-NCA (Sar-NCA) with leucine-NCA (Leu-NCA) or phenylalanine NCA (Phe-NCA) were conducted under five different reaction conditions. Benzylamine, triethylamine, pyridine and sodium methoxide (NaOMe) were used as initiators. Molar compositions of the resulting copolypeptides were determined by 1H or 13C NMR spectroscopy and reactivity ratios were calculated from copolymerizations stopped at low conversions. Sequence analyses of copolypeptides isolated at high conversions were conducted by means of 13C or 15N NMR spectroscopy. Blocky sequences were found due to a higher reactivity of Sar-NCA under all reaction conditions. The secondary structure of the solid copolypeptides was characterized by 13C NMR CP/MAS spectroscopy and WAXS powder patterns. The secondary structures are kinetically controlled and change into thermodynamically stable ones upon reprecipitation.
Databáze:	OpenAIRE
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