Blue Phosphorescent Zwitterionic Iridium(III) Complexes Featuring Weakly Coordinating nido-Carborane-Based Ligands
| Autor: | Arnold L. Rheingold, Peter I. Djurovich, A. Timothy Royappa, Alexander M. Spokoyny, Dahee Jung, Kent O. Kirlikovali, Brian Munekiyo, Vinh T. Nguyen, Jonathan C. Axtell |
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| Rok vydání: | 2016 |
| Předmět: |
010405 organic chemistry
Cationic polymerization chemistry.chemical_element General Chemistry 010402 general chemistry Photochemistry 01 natural sciences Biochemistry Catalysis 0104 chemical sciences Metal chemistry.chemical_compound Colloid and Surface Chemistry chemistry Covalent bond visual_art Polymer chemistry visual_art.visual_art_medium Carborane Iridium Methyl methacrylate Luminescence Phosphorescence |
| Zdroj: | Journal of the American Chemical Society. 138:15758-15765 |
| ISSN: | 1520-5126 0002-7863 |
| DOI: | 10.1021/jacs.6b10232 |
| Popis: | We report the development of a new class of phosphorescent zwitterionic bis(heteroleptic) Ir(III) compounds containing pyridyl ligands with weakly coordinating nido-carboranyl substituents. Treatment of phenylpyridine-based Ir(III) precursors with C-substituted ortho-carboranylpyridines in 2-ethoxyethanol results in a facile carborane deboronation and the formation of robust and highly luminescent metal complexes. The resulting nido-carboranyl fragments associate with the cationic Ir(III) center through primarily electrostatic interactions. These compounds phosphoresce at blue wavelengths (450-470 nm) both in a poly(methyl methacrylate) (PMMA) matrix and in solution at 77 K. These complexes display structural stability at temperatures beyond 300 °C and quantum yields greater than 40%. Importantly, the observed quantum yields correspond to a dramatic 10-fold enhancement over the previously reported Ir(III) congeners featuring carboranyl-containing ligands in which the boron cluster is covalently attached to the metal. Ultimately, this work suggests that the use of a ligand framework containing a weakly coordinating anionic component can provide a new avenue for designing efficient Ir(III)-based phosphorescent emitters. |
| Databáze: | OpenAIRE |
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