Electroluminesent divinylene- and trivinylene-molecules with terminal naphthalimide or phthalimide segments

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 518–586 nm, while TPP-P emitted blue light with maximum at 444–462 nm due to the kinked central core of 2,4,6-triphenylpyridine. The maximum luminance among the four molecules is 583 cd/m2 at current density of 186 mA/cm2 and applied voltage of 19.5 V based on TPA-P, with a luminance efficiency maximum (ηmax) of 1.7 cd/A.