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

A purely organic compound 2-(9 H-carbazol-9-yl)-3-(2-(2,4,5-tri-(9 H-carbazol-9-yl)-3,6-dicyanophenoxy)phenoxy)dibenzo[b,e][1,4]dioxine-1,4-dicarbonitrile, C_(76) H_(40) N_8 O_4, was synthesized and characterized by NMR, UV-Vis, photoluminescenceand X-ray single-crystal structure analysis. The compound crystallizes in monoclinic system, space group P2_1/n with a = 11.6537(3), b = 34.9738(8), c = 15.5053(3) ?, β =101.992(2)°, V = 6181.6(2)?~3, Z = 4, M_r= 1129.18 g/mol, D_c =1.396 g/cm~3, 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 exhibitsyellow-green luminescence with maximum emission peak at 538 nm, and quantum yields of ф = 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 anda long decay lifetime of 3.8ms 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 thatthe emission of the compound originates from the CT excited states.