Thiophenyl Anilato-Based NIR-Emitting Lanthanide (LnIII = Er, Yb) Dinuclear Complexes

By combining ErIII and YbIII ions with 3,6-dithiophene-anilate (Th2An) and scorpionate hydrotris(pyrazol-1-yl)borate (HBpz3−) ligands new luminescent dinuclear complexes are obtained. The two materials formulated as [((HB(pz)3)2Yb)2(μ-th2An)]·4DCM·1.3H2O 1Yb and [((HB(pz)3)2Er)2(μ-th2An)]·4DCM·1.8H2O 1Er, respectively, have been structurally characterized by SC-XRD and PXRD studies. This study presents a comprehensive investigation of the photophysical properties of the Th2An ligand for the first time. Our findings reveal the crucial role of the thiophene anilate as an effective optical antenna, which sensitizes near-infrared (NIR)-emitting lanthanide ions, specifically ErIII and YbIII. The significant impact of vibrational quenching on the LnIII NIR emission efficiency has been also highlighted.