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Abstract: Two new linear divinylenes FN and PN that contained fluorene and phenylene, respectively, as central unit and naphthalimide terminal groups were synthesized by Heck coupling. In addition, two new star-shaped trivinylenes TPA-P and TPP-P that contained triphenylamine and 2,4,6-triphenylpyridine, respectively, as central core, and terminal phthalimide groups were similarly synthesized. All molecules were very soluble in common organic solvents due to their high fraction of aliphatic moieties which were attached to the central unit and/or the terminal imides. Trivinylenes showed higher thermal stability and higher glass transition temperature (118–126°C) than divinylenes. FN, PN and TPA-P emitted green-orange light with maximum at 518–586nm, while TPP-P emitted blue light with maximum at 444–462nm due to the kinked central core of 2,4,6-triphenylpyridine. The maximum luminance among the four molecules is 583cd/m2 at current density of 186mA/cm2 and applied voltage of 19.5V based on TPA-P, with a luminance efficiency maximum (η max) of 1.7cd/A. [Copyright &y& Elsevier]

Abstract: Three new trimers PV, FV and CV were synthesized by Heck coupling of 4(4-bromophenyl)-2,6-diphenylpyridine with substituted divinylbenzene, divinylfluorene and divinylcarbazole, respectively. They were very soluble in chloroform, dichloromethane, tetrahydrofuran and toluene. FV and CV were more thermally stable and showed higher glass transition temperature than PV. Their absorption maximum was located at 327–397nm with optical band gap of 2.53–2.73eV. FV and CV emitted blue-green light with emission maximum at 455–489nm while PV emitted green-yellow light with emission maximum at 496–530nm. Upon protonation, the trimer thin films displayed red-shifts of the emission maximum. The electrochemical and electroluminescent properties of the trimers were studied. Light-emitting diodes (LEDs) based on these trimers were fabricated. These LEDs showed bright blue light for FV, CV and bluish-green light for PV which are in line with their photoluminescence spectra. The maximum brightness was reached approximate 1000cd/m2 for PV, 380 for FV, and 400 for CV, at current density of 200mA/cm2. [Copyright &y& Elsevier]