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Circular dichroism studies on the polymerization of N ‐carboxy α‐amino acid anhydride
Author(s) -
Akaike Toshihiro,
Makino Tetsuya,
Inoue Shohei,
Tsuruta Teiji
Publication year - 1974
Publication title -
biopolymers
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.556
H-Index - 125
eISSN - 1097-0282
pISSN - 0006-3525
DOI - 10.1002/bip.1974.360130108
Subject(s) - chemistry , sodium methoxide , polymerization , circular dichroism , monomer , butylamine , polymer chemistry , helix (gastropod) , polymer , crystallography , organic chemistry , methanol , ecology , amine gas treating , snail , biology
The D and L copolymerizations of N ‐carboxy γ‐benzyl glutamate anhydride (NCA) were carried out in a homogeneous solution with various D / L ratios, initiated by either n ‐butylamine or sodium methoxide, and were followed directly by circular dichroism (CD) to observe the behavior of the secondary structure of growing polymer molecules. In the n ‐butylamine system, the difference of the helical content between the righthanded and the lefthanded (Δα‐helix) gradually increased as the polymerization proceeded, while in the sodium methoxide system, the Δα‐helix had a tendency to decrease during the later stages of the polymerization. These results suggest a difference of the power of stereo‐selection of monomer antipodes by the growing chain end between these systems, the stereoselectivity by the growing chain end in the sodium methoxide system being higher than that in the n ‐butylamine system.