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Synthesis and chemical properties of polyethyleneimines crosslinked by penta‐2,4‐dienylideneammonium unit
Author(s) -
Yamaguchi Isao,
Matsumoto Yudai,
Miyoshi Kiyotaka,
Wang Aohan
Publication year - 2020
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.48712
Subject(s) - pyridinium , chemistry , electrochemistry , diethylamine , polymer chemistry , salt (chemistry) , ionic liquid , cyclic voltammetry , polymer , catalysis , electrode , organic chemistry
The reaction of N ‐(2,4‐dinitrophenyl)pyridinium anion ( salt(A) ; A = Cl − , FeCl 4 − , and (CN) 2 N − ) with linear polyethyleneimine (LPEI; M n = 20 380) and branched polyethyleneimines (BPEI1; M n = 600, BPEI2; M n = 10 000) at various molar feed ratios without using a catalyst resulted in pyridinium ring opening to yield ionic LPEI and BPEIs that were crosslinked by conjugated penta‐2,4‐dienylideneammonium (PDA) units, LPEI‐PDA , BPEI1‐PDA , and BPEI2‐PDA , respectively. A model compound was synthesized by the reaction of salt(Cl) with diethylamine. The solubilities of BPEI1‐PDA and BPEI2‐PDA depended on the feed ratios between salt(Cl) and BPEI1 or BPEI2. Dipping LPEI‐PDA into water and methanol yielded hydro‐ and organogels, respectively. UV–vis and reflection measurements revealed an expanded π‐conjugation length between the polymer chains due to the through‐space orbital interaction of the electrons on the two nitrogen atoms at the crosslinked positions in LPEI‐PDA , BPEI1‐PDA , and BPEI2‐PDA . Cyclic voltammetry analysis suggested that the polymers underwent electrochemical oxidation. Measurement using a superconducting quantum interference device (SQUID) indicated that LPEI‐PDA having FeCl 4 − anions was paramagnetic. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137 , 48712.