A magnetic site dilution approach to achieve bifunctional fluorescent thermometers and single-ion magnets.

In complex [Na-Dy(μ2-L)4]n(HL = 8-hydroxyquinoline) (1), the DyL4 units were linked by the NaI ions to form one-dimensional chains. The chain exhibited slow magnetic relaxation behavior at low temperature, accompanied by obvious quantum tunneling of magnetization (QTM). Very weak fluorescence was detected in 1 due to the mismatch of the state energy between DyIII and the L ligand. Through the magnetic dilution of diamagnetic YIII ions, complex [NaDy0.02Y0.98(μ2-L)4]n (2) was obtained; in 2 the QTM of DyIII was suppressed and the single ion magnet (SIM) behavior was enhanced. More interestingly, the fluorescence emission of 8-hydroxyquinoline was lightened by the YIII ions in 2, whose intensity is linearly correlated with the temperature variation. The examples of dual functional fluorescent thermometers and SIM materials are attained simply by ion dilution, achieving the effect of killing two birds with one stone.