A Luminescent Dinuclear EuIII/TbIII Complex with LMCT Band as a Single‐Molecular Thermosensor

Abstract Temperature‐dependent luminescence of a dinuclear EuIII/TbIII complex with a seven‐coordinate structure is demonstrated. The dinuclear complex is composed of two lanthanide ions, six tetramethylheptanedionate ligands, and a bidentate phosphine oxide linker ligand. The dinuclear structure of the complex was characterized by single‐crystal XRD. Intrinsic 4f–4f emission quantum yields of the dinuclear EuIII and TbIII complexes were 66 and 61 %, respectively. The luminescence color of the dinuclear EuIII/TbIII complex changed from red to green with increasing temperature. The thermosensing range based on the ratio of luminescence intensity (AEu/ATb) was 100–450 K. The temperature‐dependent luminescence is due to the presence of a ligand‐to‐metal charge‐transfer state.