Energy‐Transfer Mechanisms in IrIII–EuIII Bimetallic Complexes. Issue 8 (26th June 2013)

• Record Type: Journal Article
• Authors: Yu, Gang; Xing, Yadong; Chen, Fangfang; Han, Ruimin; Wang, Jianqiang; Bian, Zuqiang; Fu, Limin; Liu, Zhiwei; Ai, Xicheng; Zhang, Jianping; Huang, Chunhui
• Is Part Of: ChemPlusChem. Volume 78:Issue 8(2013:Aug.)
• Page Start: 852
• Page End: 859
• Publication Date: 2013-06-26
• Subjects: Chemistry -- Periodicals; 540.5
• DOI: 10.1002/cplu.201300107
• Languages: English
• ISSNs: 2192-6506

Abstract

<abstract abstract-type="main" xml:lang="en"> <title>Abstract</title> <p>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‐<bold>L</bold>), 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)<sub>2</sub>Ir(μ‐<bold>L</bold>)] (dfppy=2‐(4′, 6′‐difluorophenyl)pyridinato‐N, C2′), as well as their corresponding heteroleptic Ir<sup>III</sup>–Eu<sup>III</sup> complexes [{(dfppy)<sub>2</sub>Ir(μ‐L)}<sub>3</sub>EuCl]Cl<sub>2</sub> 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<sub>1</sub>) of the iridium complexes, the EET efficiency from iridium complexes to the Eu<sup>III</sup> 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<sup>III</sup>, especially energy dissipation by means of the T<sub>1</sub> state, was the main reason for the discrepancy in the quantum yields of the four Ir<sup>III</sup>–Eu<sup>III</sup> complexes.</p> </abstract>