Solvent-induced Single-Molecule Magnets Behavior and Near-infrared Luminescence properties of Rare Earth complexes
We synthesized two series of dinuclear rare earth complexes [RE2L2(acac)2(H2O)2]·i-PrOH (RE = Y (1), Eu (2), Dy (3), Ho (4), Er (5) and Yb (6)) and Dy2(L2)2(acac)2(C2H5OH)2 (7) (H2L = pyridine-2-carboxylic acid [(2-hydroxy-3-methoxyphenyl)methylene] hydrazide, Hacac = acetylacetone). The static (dc) magnetic susceptibility shows that the weak ferromagnetic interaction exists in Dy3+ of 3 and 7. Furthermore, the study of magnetization dynamics manifests that 7 possesses the energy barrier about 45 K under zero dc field, while the energy barrier of 3 is 42.93 K under the applied 800 Oe dc field by the way of a solvent-controlled crystallization. Interestingly, the energy barrier of 7 could attain 80.39 K through deteriorating the QTM. Besides, near-infrared luminescence analysis shows the ligands can be able to work as the effective sensitizing agents of 5 and 6. We observed the characteristic peaks of Er3+ and Yb3+ ions, meanwhile, complex 5 has a potential application for optical systems because the maximum peak located in the third telecommunication window about 1531 nm.