Synthesis and luminescence properties of functionalized V-shaped bis-coumarin derivatives

Three new functionalized V-shaped bis-coumarin derivatives, 3-(diethylamino)-10-(4-(1-phenyl-1H-benzo[d]imidazol-2-yl)phenyl)-6H,7H-chromeno[3,4-c]chromene-6,7-dione (VBC-BI), 3-(diethylamino)-10-(10H-phenothiazin-10-yl)-6H,7H-chromeno[3,4-c]chromene-6,7-dione (VBC-PTZ) and 3-(diethylamino)-10-(9H-carbazol-9-yl)-6H,7H-chromeno[3,4-c]chromene-6,7-dione (VBC-Cz), were successfully synthesized and characterized. Among them, the structures of VBC-PTZ and VBC-Cz were characterized by single crystal X-ray diffraction. The thermal stability and photophysical and electrochemical properties of the compounds were investigated systematically. By combining theoretical and experimental investigation, the structure-property relationships of the V-shaped bis-coumarins substituted with the electron-accepting group (benzimidazole) and the different electron-donating groups (phenothiazine and carbazole) were revealed, which could have great potential significance for the further design and synthesis of V-shaped bis-coumarins for application in OLEDs.