Details

Autor(en) / Beteiligte

• Axtell, Jonathan C
• Kirlikovali, Kent O
• Djurovich, Peter I
• Jung, Dahee
• Nguyen, Vinh T
• Munekiyo, Brian
• Royappa, A. Timothy
• Rheingold, Arnold L
• Spokoyny, Alexander M

Titel

Blue Phosphorescent Zwitterionic Iridium(III) Complexes Featuring Weakly Coordinating nido-Carborane-Based Ligands

Ist Teil von

• Journal of the American Chemical Society, 2016-12, Vol.138 (48), p.15758-15765

Ort / Verlag

United States: American Chemical Society

Erscheinungsjahr

2016

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• 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.