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Blue Emission of a Soluble Poly( p ‐phenylene) with a Cross‐Conjugated Bisimidazole‐Based Chromophore
Author(s) -
Dierschke Frank,
Müllen Klaus
Publication year - 2007
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.200600412
Subject(s) - chromophore , phenylene , conjugated system , polymer chemistry , poly(p phenylene) , cyclic voltammetry , steric effects , band gap , electroluminescence , materials science , photochemistry , cruciform , polymer , solubility , chemistry , electrochemistry , organic chemistry , electrode , optoelectronics , layer (electronics) , composite material
A novel poly( p ‐phenylene) ( 6 ) has been synthesized by a cruciform combination of a polyphenylene backbone with 2,2′‐( p ‐phenylene)‐bis(4,5‐diphenylimidazole) ( 5 ) as an additional, orthogonal chromophore. Polymer 6 showed in solution and in the solid state, a blue‐green emission, which is obviously arising from the second bisimidazole‐based chromophore. UV‐Vis spectroscopy, and cyclic voltammetry revealed that the optical and electronic properties of 6 were fully determined by the incorporated 2,2′‐(1,4‐phenylene)bisimidazole structure. The bisimidazole unit led to high solubility and, despite the steric demand of the substituents, at the same time to the blue‐green emission of the poly( p ‐phenylene) ( 6 ). In addition, the oxidation of 6 with potassium ferricyanide yielded a low bandgap polymer with a quinoid‐type structure and a bandgap of 1.6 eV.