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Tröger's Base‐Containing Aromatic Polymers with Unexpected Properties Endowed by the Insertion of Alkyne Spacers
Author(s) -
Li Wei,
Michinobu Tsuyoshi
Publication year - 2016
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.201500494
Subject(s) - triphenylamine , polymer chemistry , polymer , monomer , copolymer , redox , fluorene , quantum yield , chemistry , materials science , photochemistry , fluorescence , organic chemistry , physics , quantum mechanics
Novel Tröger's base‐containing linear polymers are synthesized by the Pd‐catalyzed polycondensation of 2,8‐disubstituted Tröger's base monomers. Despite the nonplanarity of Tröger's base structure, there is a solubility problem for the resulting polymers. Careful selection of the comonomers and π‐spacers eventually produce high molecular weight polymers. All the polymers show high thermal stabilities with decomposition temperatures ( T d5% ) exceeding 300 °C. The optical and electrochemical properties of Tröger's base‐containing polymers are, to the best of our knowledge, investigated for the first time. They absorb UV light and emit a blue fluorescence in CH 2 Cl 2 solutions with the quantum yield reaching 0.72. The polymers with ethynylene spacers display a remarkable light‐green fluorescence in thin films as a result of excellent intermolecular interactions. Also, the redox activities depend on the chemical structures of the comonomers and π‐spacers. Remarkably, Tröger's base‐fluorene copolymer does not show any oxidation peaks, whereas the ethynylene‐linked copolymer exhibits a well‐defined oxidation at ≈1.1 V (vs Ag/Ag + ). The use of triphenylamine comonomers further enhances the redox activities. A facilitated oxidation occurs at the benzidine subunits, and a faster redox response is revealed by spectroelectrochemical measurements.