Heteroleptic (C-N)2Ir(acac) complexes bearing o-carborane substituted phenylpyridine ligand (C-N = 4-CBppy (1  ); 5-CBppy (2  ), CB = ortho-methylcarborane; ppy = 2-phenylpyridinato-C2,N, acac = acetylacetonate) were prepared and characterized. While 1  exhibited a red-shifted phosphorescence band compared to that for unsubstituted (ppy)2Ir(acac) (3  ) (?em = 516 nm), the emission spectrum of 2  showed a blue-shifted band by 13 nm. Experimental and TD-DFT calculations suggest that carborane substitution on 4-position of phenyl ring lowers the 3MLCT energy by the large contribution of carborane cage into LUMO delocalization while the substitution on 5-position raises it by the effective stabilization of HOMO level due to a strong inductive effect of carborane. Details of synthesis, characterization, and photophysical properties of complexes will be discussed.

Ir(III) complexes based on <i>o</i>-carborane substituted phenylpyridine ligands: Unusual phosphorescence color tuning

243rd National Meeting (2012)

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Ir(III) complexes based on o-carborane substituted phenylpyridine ligands: Unusual phosphorescence color tuning