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Energy‐Transfer Mechanisms in Ir III –Eu III Bimetallic Complexes
Author(s) -
Yu Gang,
Xing Yadong,
Chen Fangfang,
Han Ruimin,
Wang Jianqiang,
Bian Zuqiang,
Fu Limin,
Liu Zhiwei,
Ai Xicheng,
Zhang Jianping,
Huang Chunhui
Publication year - 2013
Publication title -
chempluschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.801
H-Index - 61
ISSN - 2192-6506
DOI - 10.1002/cplu.201300107
Subject(s) - iridium , chemistry , bimetallic strip , phosphorescence , excited state , bridging ligand , photochemistry , bipyridine , europium , ligand (biochemistry) , triplet state , ion , crystallography , fluorescence , atomic physics , molecule , crystal structure , catalysis , organic chemistry , biochemistry , physics , receptor , quantum mechanics
The bridging ligands in d–f bimetallic complexes play an important role in the excitation energy transfer (EET) process. To elaborate on the effect of the ligand on the EET process, a series of bridging ligands (μ‐ L ), 1‐(1′,10′‐phenanthrolin‐2′‐yl)‐4,4,4‐trifluorobutane‐1,3‐dione (phen3f), 1‐(1′,10′‐phenanthrolin‐2′‐yl)‐4,4,5,5,5‐pentafluoropentane‐1,3‐dione (phen5f), 1‐(2,2′‐bipyridine‐6‐yl)‐4,4,4‐trifluorobutane‐1,3‐dione (bpy3f), and 1‐(2,2′‐bipyridine‐6‐yl)‐4,4,5,5,5‐pentafluoropentane‐1,3‐dione (bpy5f), and their corresponding iridium complexes, [(dfppy) 2 Ir(μ‐ L )] (dfppy=2‐(4′,6′‐difluorophenyl)pyridinato‐N,C2′), as well as their corresponding heteroleptic Ir III –Eu III complexes [{(dfppy) 2 Ir(μ‐L)} 3 EuCl]Cl 2 were synthesized and characterized. Photophysical and kinetic results revealed that the alternation of the bridge ligand resulted in a systemic difference in the lowest triplet‐state energy (T 1 ) of the iridium complexes, the EET efficiency from iridium complexes to the Eu III ion, and a significant difference in the total luminescence quantum yields. Based on the nanosecond time‐resolved phosphorescence spectra, a model for the energy‐transfer mechanism was proposed for d–f bimetallic complexes, which indicated that the nonradiative relaxation of the excited energy of Eu III , especially energy dissipation by means of the T 1 state, was the main reason for the discrepancy in the quantum yields of the four Ir III –Eu III complexes.