3-Pyridylacetic-Based Lanthanide Complexes Exhibiting Magnetic Entropy Changes, Single-Molecule Magnet, and Fluorescence

Four complexes from lanthanides, 3-pyridylacetate, and 1,10-phenanthroline, formulated as [Ln(2)(3-PAA)(2)(mu-Cl)(2)(phen)(4)](ClO4)(2) [Ln = Gd(1), Dy(2), Eu(3), Tb(4), 3-PAA = 3-pyridylacetic acid, phen = 1,10-phenanthroline], were obtained. The four compounds were characterized by IR spectra, thermogravimetric analyses, powder X-ray diffraction, and single-crystal X-ray diffraction. Compounds 1-4 are isomorphous, and they have a dinuclear structure. Magnetic studies reveal that 1 shows the magnetocaloric effect with -Delta S-m(max) = 19.03 J kg(-1) K-1 at 2 K for Delta H = 5 T, and 2 displays a field-induced single-molecule magnet with U-eff = 19.02 K. The photoluminescent spectra of 3 and 4 exhibit strong characteristic emission, which demonstrate that the ligand-to-Eu-III/Tb-III energy transfer is efficient.

Automated summary

Four lanthanide complexes were synthesized and characterized, showing specific structures and magnetic properties. Efficient energy transfer from the ligand to Eu-III/Tb-III was observed.