Conformation Transformation And Emission Properties Of Tris (2-phenyipyridine) Iridium(Ⅲ) Complexes

Since1987, C. W. Tang fabricated double-layer efficientelectroluminescent devices by using NPB/Alq3, organic electroluminescenttechnology has attracted widespread attention. Because of its lightweight,ultra-thin, high resolution, low power consumption, fast response, andmany other advantages, it is regarded as the most promised displaytechnique of the next generation. In particular, the developments ofphosphorescent materials effectively improve the performances of theelectroluminescent devices, and promote the organic electroluminescenttechnology reaches a new height. Tris(2-phenylpyridine)iridium (Ⅲ) is awidely used green phosphorescent material, which possesses two types ofconfigurations, meridianal isomer and facial isomer, and their physical andchemical properties are quite different to each other. Because of the badstability and luminous efficiency of the meridianal isomer, the widely used isthe facial isomer. However, the synthesis of facial isomer is mostly carriedout at high temperatures (above200℃), and it is difficult to perform.Therefore, the developments of the synthesis route of facial isomer and theconversion method from meridianal isomer to facial isomer are especialurgent.The paper is focused on selected synthesizing of the facial isomer atrelative low temperature and conversing meridianal isomer to facial isomer.Furthermore, the optical properties of the two isomers are investigated. Westudied six tris(2-phenylpyridine)iridium[Ⅲ] derivatives. In the secondchapter, three facial isomers of iridium complexes are synthesized by using a new method, and three meridianal isomers of iridium complexes aresynthesized by using a classical method, and these six complexes areconformed by1HNMR, MS and elemental analysis. The synthesis of facialisomers are performed at blew140℃and avoided the high temperature.In the third chapter, four different methods are tested for the isomerizationfrom meridianal isomer to facial isomer. In addition, the photophysicalproperties of the six iridium complexes are investigated in both solution andsolid state.The synthesis route of facial isomer and the conversion method frommeridianal isomer to facial isomer are mainly aimed attris(2-phenylpyridine)iridium (Ⅲ) and its derivatives. But they are believedthat the synthesis route and the conversion method in this paper couldprovide some recommendations to the other iridium complexes.