A new series of N-substituted tetraphenylethene-based benzimidazoles: Aggregation-induced emission, fast-reversible mechanochromism and blue electroluminescence

Four new N-substituted tetraphenylethene-based benzimidazoles N-R-2-(4-(1,2,2-triphenylvinyl) phenyl)-1H-benzofdlimidazoles (R = phenyl (3a), R = 4-(tert-butyl)phenyl (3b), R = n-butyl (3c), R = n-hexyl (3d)) were synthesized conveniently by cyclization reaction of 4-tetraphenylenthenealdehyde with N-substituted ortho-nitroaniline. The four compounds exhibit typical aggregation-induced emission (AIE) property with relatively high solid state absolute fluorescence quantum yields (381-65.7%) and fast-recoverable mechanochromism property with solid-state fluorescence change between blue and yellow-green. They are thermally stable with decomposition temperatures above 319 degrees C. Both of multilayer electroluminescence devices fabricated with compounds 3b and 3c as emitters are blue emission. The turn-on voltage of device based on compound 3b is 3.3 V with maximum luminance and current efficiency of 2470 cd/m(2) and 1.48 cd/A, respectively. (C) 2017 Elsevier Ltd. All rights reserved.