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Polymerization of Substituted Acetylenes Using Well‐Defined Rhodium Complex Catalyst. Chirality Transfer and Amplification in Chiral‐Chiral Block and Random Copolymers
Author(s) -
Goto Masahide,
Nito Ayaka,
Miyagi Yu,
Sanda Fumio
Publication year - 2019
Publication title -
macromolecular materials and engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.913
H-Index - 96
eISSN - 1439-2054
pISSN - 1438-7492
DOI - 10.1002/mame.201900275
Subject(s) - copolymer , polymerization , chirality (physics) , materials science , polymer chemistry , circular dichroism , block (permutation group theory) , polymer , crystallography , chemistry , chiral symmetry , combinatorics , mathematics , physics , composite material , quantum mechanics , nambu–jona lasinio model , quark
Block and random copolymers are synthesized by the copolymerization of N ‐ tert ‐butoxycarbonyl‐ʟ‐valine 4‐ethynylanilide ( 1L ) and N ‐ tert ‐butoxycarbonyl‐d‐valine 4‐ethynylanilide ( 1D ) using [(nbd)Rh{C(Ph) = CPh 2 }(PPh 3 )]/PPh 3 as a catalyst. The size exclusion chromatography (SEC) peaks show narrow polydispersities from the first stage polymerization to the second one in the block copolymerization. Poly( 1L 25 ‐ ran ‐ 1D 25 ) exhibits no circular dichroism (CD) signal, while poly( 1L 25 )‐ block ‐poly( 1D 25 ) exhibits weak CD signals with the same sign as those of poly( 1L 50 ), suggesting the occurrence of chirality transfer from the poly( 1L ) block to poly( 1D) block. The relationship between the | g | values and 1L / 1D contents of the block copolymers becomes almost linear at the region of each unit larger than 60%. On the other hand, the relationship between these two factors of the random copolymers is convex upward.