Synthesis, Crystal Structure and Photophysical Property of 2-(9H-carbazol-9-yl)-3-(2-(2,4,5-tri-(9H-carbazol-9-yl)-3,6-dicyanophenoxy)phenoxy) dibenzo b,e 1,4 dioxine-1,4-dicarbonitrile

摘要

A purely organic compound 2-(9H-carbazol-9-yl)-3-(2-(2,4,5-tri-(9H-carbazol-9-yl)-3,6-dicyanophenoxy)phenoxy)dibenzo[b,e][1,4]dioxine-1,4-dicarbonitrile,C76H40N8O4,was synthesized and characterized by NMR,UV-Vis,photoluminescence and X-ray single-crystal structure analysis.The compound crystallizes in monoclinic system,space group P21/n with a =11.6537(3),b =34.9738(8),c =15.5053(3) (A),β =101.992(2)°,V =6181.6(2) (A)3,Z =4,Mr =1129.18 g/mol,Dc =1.396 g/cm3,F(000) =2672,μ =2.239 mm-1,GOOF =1.019,the final R =0.0577 and wR =0.1559 for 11925 observed reflections with I ＞ 2σ(I).The UV-vis absorption and fluorescence of the compound were discussed.The compound exhibits yellow-green luminescence with maximum emission peak at 538 nm,and quantum yields of φ =0.25 and 0.48 in air-equilibrated and degassed toluene at room temperature.Transient decay spectral studies show that compound 1 displays two component decay fashions with a short decay lifetime of 23 ns for the prompt fluoresce and a long decay lifetime of 3.8 μs for thermally activated delayed fluorescence.In air-equilibrated toluene,only a short decay lifetime of 17 ns was observed.The experimental and computational results show that the emission of the compound originates from the CT excited states.