Synthesis and photophysical properties of Ir-III-Ln(III) (Ln = Nd, Yb, Er) bimetallic complexes containing bipyrimidines as bridging ligands

Bipyrimidines have been chosen as ((NN)-N-boolean AND)((NN)-N-boolean AND) bridging ligands for connecting metal centers. Ir-III-Ln(III) (Ln = Nd, Yb, Er) bimetallic complexes [Ir(dfppy)(2)(mu-bpm)Ln(TTA)(3)]Cl were synthesized by using Ir(dfppy)(2)(bpm)CI as the ligand coordinating to lanthanide complexes Ln(TTA)(3).2H(2)O. The stability constants between Ir(dfppy)2(bpm)CI and lanthanide ions were measured by fluorescence titration. The obvious quenching of visible emission from Ir-III complex in the Ir-III-Ln(III) (Ln = Nd, Yb, Er) bimetallic complexes indicates that energy transfer occurred from Ir center to lanthanides. NIR emissions from Nd-III, Yb-II, and Er-III were obtained under the excitation of visible light by selective excitation of the Ir-III-based chromophore. It was proven that Ir(dfppy)(2)(bpm)CI as the ligand could effectively sensitize NIR emission from Nd-III, Yb-III, and Er-III.Chemistry, MultidisciplinarySCI(E)EI4ARTICLE11,SI1808-18135