ic701817n_si_002.cif (81.28 kB)

Highly Efficient Sensitized Red Emission from Europium (III) in Ir−Eu Bimetallic Complexes by 3MLCT Energy Transfer

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posted on 07.04.2008, 00:00 by Fang-Fang Chen, Zu-Qiang Bian, Zhi-Wei Liu, Dao-Bo Nie, Zhu-Qi Chen, Chun-Hui Huang
Two novel iridium−europium bimetallic complexes, {[(dfppy)2Ir(μ-phen5f)]3EuCl}Cl2 and (dfppy)2Ir(μ-phen5f)Eu(TFAcA)3 [dfppy represents 2-(4′,6′-difluorophenyl)-pyridinato-N,C2, phen5f stands for 4,4,5,5,5-pentafluoro-1-(1′,10′-phenanthrolin-2′-yl)-pentane-1,3-dionate and TFAcA represents trifluoroacetylacetonate], were successfully synthesized. The novel ligand Hphen5f with four coordination sites was designed as a bridge to link the IrIII center and the EuIII center. The X-ray diffraction data shows that the nonbonding distances for Eu···Ir are 6.028, 5.907, and 6.100 Å in the bimetallic complex {[(dfppy)2Ir(μ-phen5f)]3EuCl}Cl2. Photophysical studies implied that the high efficient red luminescence from the EuIII ion was sensitized by the 3MLCT (metal-to-ligand charge transfer) energy based on an IrIII complex-ligand in a d-f bimetallic assembly. The excitation window for the new bimetallic complex {[(dfppy)2Ir(μ-phen5f)]3EuCl}Cl2 extends up to 530 nm (1 × 10−3 M in EtOH), indicating that this bimetallic complex can emit red light under the irradiation of sunlight.