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Synthesis of Helical Poly(Phenyleneethynylene‐Pyromellitic Diimide)s and the Responsiveness of the Helicity to Solvents, Heat, and pH
Author(s) -
Liu Ruiyuan,
Sanda Fumio,
Masuda Toshio
Publication year - 2009
Publication title -
macromolecular chemistry and physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.57
H-Index - 112
eISSN - 1521-3935
pISSN - 1022-1352
DOI - 10.1002/macp.200800503
Subject(s) - polymer chemistry , diimide , polymer , polymerization , chemistry , condensation polymer , pyromellitic dianhydride , copolymer , sonogashira coupling , materials science , organic chemistry , molecule , layer (electronics) , catalysis , palladium , perylene , polyimide
N , N ′‐bis‐( L ‐4′‐iodophenylalanine octyl ester)pyromellitic diimide ( 1 ) was synthesized, and the Sonogashira–Hagihara coupling polymerization of 1 with para ‐/ meta ‐diethynylbenzenes ( 2p / 2m ) was carried out to obtain optically active phenyleneethynylene‐based polyimides carrying ester groups [poly( 1 ‐ 2p ) and poly( 1 ‐ 2m )] with number average molecular weights in the range from 4 900 to 19 700 in 68–80% yields. The polymers were satisfactorily converted into the corresponding polymers carrying free carboxy groups [poly( 1 ‐ 2p )′ and poly( 1 ‐ 2m )′] by alkaline hydrolysis. All the polymers exhibited intense CD signals, indicating that they formed helices with predominantly one‐handed screw sense. The helical conformations of the polymers were stable against heat. Poly( 1 ‐ 2p )′ and poly( 1 ‐ 2m )′ lost the one‐handed helicity by the addition of NaOH, and the resultant polymer recovered the original conformation upon HCl addition.