Design,Synthesis,Photophysical Properties And Application Of Phosphorescent Iridium Complex With N-H Moiety In Ligand

Due to their excellent photophysical properties, such as high phosphorescence quantum efficiency, significant Stokes shifts and rich excited-state properties, phosphorescent iridium(III) complexes have been widely applied in electroluminescent devices, chemical sensors, bio-imaging and so on. Most of tuning strategies of photophysical properties for iridium(III) complexes are mainly based on the chemical modification of ligand skeleton or the synthesis of new ligands. However, these strategies generally require complex chemical reactions or high cost. A new non-covalent bond method(hydrogen bond) that can regulate the photophysical properties of iridium(III) complexes have been proposed in the previous study of our group. This method does not change the skeleton of cation complexesbut just change the counter anions of complexes, as a result, the luminescence color of complex can be changed effectively(about 50 nm). In order to achieve a wide range of emission wavelength tuning by hydrogen bond, a series of ionic iridium(III) complexes have been designed and synthesized by selecting N^N ligand with one or two N-H moieties. And the photophysical properties and its potential application in information storage have been studied. The main research contents are as follows:1) we selected N^N pyridylimidazole(bm) which containing a N-H moiety as ancillary ligand, a series of iridium(III) complexes with different C^N main ligand(2-(2,4-difluorophenyl)pyridine(2Fppy), 2-phenylpyridine(ppy) and 9-heptyl-3-(pyridin-2-yl) –carbazole(czpy)) have been designed and synthesized. By studying the photophysical properties of these iridium(III) complexes, it showed that coanion can only regulate the photophsical properties of some cationic complexes. As a result, the hydrogen bond can not control photophysical properties of all iridium(III) complexes when the energy of ancillary ligand with N–H moiety is too high.2) we selected 2-phenylpyridine(ppy) as main ligand, another three kinds of ionic iridium(III) complexes with 2-(2-pyridyl)imidazole(bm), 2-(2-pyridyl)benzimidazole(bpm) and benzimidazol-2-yl-quinoline(qpm) as auxiliary ligand which all contain a N–H moietyhave been designed and synthesized. By studying the photophysical properties of these iridium(III) complexes, it showed that coanion can regulate the photophsical properties of some anion complexes effectively.3) we selected 9-heptyl-3-(pyridin-2-yl)–carbazole(czpy) as main ligand, another two kinds of ionic iridium(III) complexes with 2,2′-biimidazole(dm) and 2,2’-bisbenzimidazole(dpm) as auxiliary ligand which all containing two N–H moieties have been designed and synthesized. By studying the photophysical properties of these iridium(III) complexes, it showed that coanion can regulate photophysical properties more effectively(about 100 nm) with the increasing of the number of N-H moieties..In addition, the complexes have external stimulus-responsive, such as pH value or electric field. Finally, a information encryption storage device have been designed based on(czpy)2IrdpmPF6 which via FLIM and TGLI can realize information decryption.