Synthesis And Photophysical Properties Of Bis-tetraphenylene-diones

1-phenyl-2,4,5-tetrastyryl-1H-imidazole(3TPEI)is a blue light-emitting OLED molecule with potential applications in many fields.3TPEI has superior Potophysical properties and electrochemical properties.Bis-tetraphenylethene-diones(Bis-TPE-diones)can be served as the key precursors for the synthesis of 3TPEI and other blue light-emitting OLED materials.However,only one protocol has been reported concerning the synthesis of Bis-TPE-diones.The reported method encountered drawbacks arising from the difficultly prepared starting materials as well as the anaerobic reaction condition.It will have significance in theoretical research and in practical work if we can use cheap,ready available starting materials to prepare the Bis-TPE-diones with simple reactions and easily handle protocols.In this dissertation,Bis-TPE-diones with different dicarbonyl chains as linkers have been facilely synthesized by F-C acylation in one step for the first time.Since the TPE groups are prototypical aggregation-induced emission(AIE)units,the AIE properties,solavatochromism and mechanochromism of the Bis-TPE-diones have also been systematically studied.The Bis-TPE-diones exhibited notable AIE properties and their maximum fluorescence in THF can be turned on by low water fractions(f_w,10%-40%).The f_w to turn on the maximum fluorescence are closely associated with the dicarbonyl chains in the Bis-TPE-diones as the following sequence:conjugate chain(fumaryl,f_w=10%)<flexible long chain(succinyl,f_w=20%<glutaryl,f_w=30%)<short chain(1,2-dicarbonyl,f_w=40%).This result could be ascribed to the different polarities and conformations of the Bis-TPE-diones.The Bis-TPE-diones also exhibited notable solvatochromism and observable mechanochromism.