Synthesis And Luminescence Properties Of V-shaped Coumarin-oxadiazole Derivatives

Organic luminescent materials are increasingly used in people's lives,due to their applications in thin-film-transistors,light-emitting diodes,solar cells,sensors,and many others.In this paper,we first designed and synthesized a dimethyl silicon as the center,the coumarin group as a fluorophore at the same time as an electron donor,1,3,4-oxadiazole unit as a strong electron acceptor group.So,a novel,symmetric,V-shaped,multifunction material was accepted.We show that the Si atom induces a V-shaped structure that weakens ?-? stacking and thus limits aggregation-induced quenching.As expected,a gradual transition from a locally excited state to an intramolecular charge-transfer state is observed with increasing solvent polarity.This new type of compound exhibits tunable light emission,which the color gradually redshifts from blue to green in solution.And the designed target compounds not only showed strong fluorescence in the solution state,but also had strong fluorescence in the undoped solid film state.Experiments also demonstrate that the compound has a better ability to transmit electrons and holes,which is of great significance to the application of luminescent materials.To explore the effect of increasing the charge transfer in the molecule,we also designed and synthesized a sulfonyl group as the center,including coumarin-containing groups and 1,3,4-oxadiazole units,a V-shaped symmetric compounds.Theoretical calculations show that the compound has a stronger intramolecular charge transfer characteristics.The compound inherits and further improves the excellent properties of the first compound.It exhibits tunable light emission and has a larger Stokes shifts in different polar solvents,with a wider range of light,from blue to orange,covering the entire visible area except the red color.The compound also shows Aggregation-induced Emission,showing strong fluorescence in both solution and solid state.The unique optical properties exhibited of the target compound,coupled with excellent thermal stability and electrochemical properties making it a versatile emitter.