Title
Synthesis and chemical properties of conjugated polymers with bis(trifluoromethanesulfonyl)imide and bis(nonafluorobutanesulfonyl)imide anions
Author
Isao Yamaguchi, Gintaro Nagase, Aohan Wang
Year
2019
Journal
European Polymer Journal
Abstract
The reaction of N-(2,4-dinitrophenyl)pyridinium chloride (salt(Cl−)) with lithium bis(trifluoromethanesulfonyl)imide (TFSI−LI+) and lithium bis(nonafluorobutanesulfonyl)imide (NFSI−LI+) resulted in the anion exchange between Cl− and TFSI− and Cl− and NFSI− that yielded new Zincke salts, namely salt(TFSI−) and salt(NFSI−), respectively. The reaction of salt(TFSI−) with piperazine, (R)-(–)- or (S)-(+)-2-methylpiperazines in methanol without the use of a catalyst resulted in the opening of pyridinium ring to yield ionic polymers with 5-piperazinium-2,4-dienylideneammonium bis(trifluoromethanesulfonyl)imide or 5-(2-methylpiperazinium)-2,4-dienylideneammonium bis(trifluoromethanesulfonyl)imide units, namely polymer(H;TFSI−), polymer(R-Me;TFSI−), and polymer(S-Me;TFSI−), respectively. The reaction of salt(NFSI−) with piperazine yielded polymer(H;NFSI−) having a 5-piperazinium-2,4-dienylideneammonium bis(trifluoromethanesulfonyl)imide unit. Model compounds with TFSI− or NFSI− were synthesized to compare their structures and chemical propeties with those of the corresponding polymers. UV–vis measurements revealed that the π-conjugation system expanded along the polymer chain due to the orbital interaction between the electrons on the two nitrogen atoms of the piperazinium or 2-methylpiperazinium rings. Cyclic voltammetry analysis suggested that the polymers obtained in this study received electrochemical oxidation and reduction.
Instrument
V-560, J-720
Keywords
Absorption, Circular dichroism, Stereochemistry, Polymers, Optical properties