| 초록 |
In order to understand the causes of the emission shape and colour changes of heteroleptic Ir3+ complexes containing 2-(2,4-difluorophenyl)pyridine (dfppy) as the main ligands, we introduced two types of ancillary ligands: (1) non-luminescent ancillary ligands, namely tetrakis(pyrazolyl)borate (bor) and picolinate (pic), which were employed for the preparation of Ir(dfppy)2(bor) and Ir(dfppy)2(pic), respectively, and (2) luminescent ancillary ligands, namely 1,10-phenanthroline (phen), bipyridine (bpy), and 2,3-dipyridylpyrazine (dpp), which were employed for the preparation of Ir(dfppy)2(phen), Ir(dfppy)2(bpy), and Ir(dfppy)2(dpp), respectively. The anomalous rigidochromism was attributed to an interligand energy transfer (ILET), and showed a strong temperature dependence. The ILET occurs from dfppy to the other ligands lying in lower energy states. The ILET dynamics were probed directly using femtosecond transient absorption (TA) spectroscopy after the excitation of dfppy. |
