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Published on: March 9, 2017
Luminescent IrIII-AuI Heterobimetallic Complex with a Carbene Bridging Ligand
Felipe Canisares1,2, Mattia Di Niro3, Ana M Pires1,4
1Institute of Chemistry, Universidade Estadual Paulista (UNESP, São Paulo State University), Araraquara 14800-060, Brazil.
None:
IrIII-AuI luminescent bimetallic complexes have drawn growing interest for applications in photonics, catalysis, and biomedicine. Here, we report the synthesis of a new photoluminescent IrIII-AuI complex, the [(ppz)2Ir(μ-bbip)AuBr]PF6, incorporating 1,3-dibenzyl-1H-imidazo[4,5-f][1,10]phenanthrolin-3-ium bromide (bbip) as a bridging N-heterocyclic carbene (NHC) ligand. Among the various characterizations employed, single-crystal X-ray diffraction (SC-XRD) confirmed the structure of the complex, validating the proposed molecular formulation and coordination sphere. For comparative purposes and under similar conditions, the monometallic IrIII complex [Ir(ppz)2(bbip)](PF6)2 was synthesized and also validated by SC-XRD. Both complexes showed broad UV-vis excitation and orange-to-red emission in all tested solvents. Notably, the IrIII-AuI complex exhibited lower solvent polarity sensitivity than the mono-IrIII analog, with AuI coordination to bbip causing a slight emission blue shift. The incorporation of AuI significantly enhanced the photoluminescent properties, doubling both, the emission lifetime (τ) from 278 to 554 ns and the quantum yield (Φ) from 25 to 61% in degassed DCM. Notably, Φ remained high (30%) even in air-equilibrated DCM.
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