Synthesis And Optical Properties Of Platinum(?) Complexes Based On Phenothiazine Derivatives

Over the past decades organic light-emitting diodes(OLEDs)have gained increasing concerned in both academic research and commercial.People are committed to improving the brightness and efficiency of OLEDs,which requires that the materials have good electron and hole transport ability.The hole transport ability of phenothiazine is stronger than carbazole and other groups.The nonplanar structure of phenothiazine,can prevent ?-? stacking,thus,it is possible to improve the electroluminescence efficiency.So we choose the non-planar and the oxidation of the sulfur atom of phenothiazine,hoping to turn the color by oxidizing S atom.In this paper,a series of platinum(?)complexes based on phenothiazine derivatives were designed,synthesized and investigated.1.Synthesis and optical properties of bidentate platinum(?)complex based on phenothiazine derivativesThree bidentate platinum(?)complexes Pt-1~Pt-3 based on phenothiazine were synthesized and characterized.The photophysical properties of the ultraviolet-visible absorption(UV-Vis),fluorescence spectra(PL)and cyclic voltammetry(CV)are tested.The maximum emission peaks of three complexes in the solution are shifted from 530 nm of Pt-1 to 465 nm of Pt-3,which from green to blue,and the quantum efficiency increased from 37.36% to 55.3%,indicating that the luminescence color and the luminescence efficiency are improved based on the sulfoxide and sulfone structure of phenothiazine.2.Synthesis and optical properties of tetradentate platinum(?)complexes based on the phenothiazine derivatives with asymmetric structureWe designed and synthesized three tetradentate platinum(?)complexes with asymmetric structures based on phenothiazine.The UV-Vis,PL and CV are tested.The Pt-4 shown a maximum emission peak at 510 nm,after oxidation,the Pt-5 and Pt-6 shown blue shifted of 43 and 50 nm,respectively.However,the luminescence intensity of Pt-5 and Pt-6 fell down,and the quantum efficiency decreased,which may be caused by the mismatching of energy between the ligand and metal center.3.Synthesis and optical properties of tetradentate platinum(?)complexes based on phenothiazine derivatives with symmetric structureTwo tetradentate platinum(?)complexes Pt-7 and Pt-8 with symmetric structure based on phenothiazine were designed,synthesized and characterized.The UV-Vis,PL and CV are tested.In the solution,the maximum emission peaks of the two platinum(?)complexes were at 542 and 495 nm,respectively.After oxidation of the S atom on phenothiazine by strong oxidant,the Pt-8 of complexes containing the two sulfone structure was obtained,and the quantum efficiency increased from 46.9% to 54.28%,indicating that the sulfone structure based on phenothiazine was beneficial to the enhancement of quantum efficiency.