Novel π-conjugated molecules based on diimidazopyridine: Significantly improved the photophysical, thermal and electrochemical properties bearing different aryl substituents

Abstract

A series of π-conjugated molecules based on diimidazolepyridine derivatives were designed, synthesized by Suzuki coupling reaction and cyclization reaction and characterized. Diimidazolepyridine motif as the main structure could improve the thermal stability and optical property of the materials. All of the target compounds exhibited good thermal stabilities with Td values in the range of 416–490 °C. These compounds showed steady blue light emissions in the range of 424–478 nm and high quantum yields (0.33–0.69) in solution. Especially, compound 4f achieved appropriate energy gap (Eg = 2.69 eV) and high fluorescence quantum yields (Φf = 0.69) because of introducing electron-donating group, such energy gap was helpful to electronic transfer and transport. The materials have great potential for good electronic-transmission materials in OLEDs.