Structure-Photoluminescence Quenching Relationships of Iridium(III)-Tris(phenylpyridine) Complexes

The synthesis, structural, photophysical, theoretical, and electrochemical characterization of four tris(2-phenylpyridine)-based IrIII complexes are reported. The complexes were functionalized on the pyridine or on the phenyl rings with amide moieties substituted with a tris(ethyl)amine or ethyl groups, thereby yielding a family of compounds with hemicaged or open (without a capping unit but with similar functional groups on the ligand) structure. Within the context of the parent tris(2-phenylpyridine) and the full-cage iridium(III) complexes, structure–photoluminescence quenching relationships (SPQR) of the four complexes have been investigated. Luminescence quenching by oxygen has been studied with Stern–Volmer plots and through evaluation of the thermodynamic parameters involved in the quenching process. Density functional theory (DFT) and time-dependent DFT (TD-DFT) calculations have been performed on th