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

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.