| 초록 |
In the last decade, phosphorescent iridium(III) complexes have been widely used in organic light-emitting diodes (OLEDs), chemosensors, and bioimaging owing to their stable chemical structure, high luminescent efficiency, and tunable excitation and emission wavelength over the whole visible range. However, few carborane-based phosphorescent iridium(III) complexes have been reported. It is anticipated that introduction of carborane cages into phosphorescent iridium(III) complexes may further improve the photophysical properties of these complexes and allow better understanding the roles of carborane groups. In this communication, we synthesized iridium(III) complexes containing o-carborane in the various cyclometalated C^N ligand . The tuning of phosphorescence color has usually been achieved by the variation of the substituent on the C^N ligand. The variation in the excited state energy has usually been made by changing the electronic structure of the C^N ligand, which affects the energy levels of highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO). In this regard, we have recently reported that the introduction of o-carborane (1,2-closo-C2B10H12) to the 4- or 5- position of the phenyl ring of a ppy ligand in (C^N)2Ir(acac), (C^N)2Ir(pic) and (C^N)3Ir complexes gives rise to red and blue shifts of the phosphorescence band, respectively, when compared to the emission wavelength of (tphpy)2Ir(acac), (tphpy)2Ir(pic) and Ir(tphpy)3. |
