含区位异构氨基萘酰亚胺配体的环Ir配合物三重态光敏剂的合成、光物理性质以及在三重态湮灭上转换中的应用
摘要
Visible light-harvesting cyclometalated Ir(Ⅲ) complexes showing long-lived triplet excited states were prepared with regioisomeric aminonaphthaleneimide ligands. The photophysical properties of the complexes were studied with steady state and time-resolved spectroscopies, as well as DFT calculation. Compared to the known cyclometalated Ir(Ⅲ) complexes, the new complexes show ligand-localized triplet excited state (<sup>3</sup>IL state), instead of the normal <sup>3</sup>MLCT state. The two complexes with regioisomeric NI ligands show drastically different photophysical properties, such as phosphorescence quantum yields. The complexes were used as triplet photosensitizer for triplet-triplet annihilation (TTA) upconversion. TTA upconversion quantum yield up to 19.3% was observed. These results are useful for preparation of visible light-harvesting Ir(Ⅲ) complexes and for the study of the triplet excited state of organic chromophores.