A Pair of Chiral Dysprosium Single-Ion Magnets with 2,6-Bis[(4S/4R)4-phenyl-2-oxazolinyl]pyridine and Hexafluoroacetylacetonate Ligands

Employing 2,6-bis[(4S/4R)-4-phenyl-2-oxazolinyl]pyridine (4R/4S-Pybox) as the chiral inducing ligand, a pair of enantiopure mononuclear Dy(III) complexes, [Dy(Hfac)3(4R/4S-Pybox)] (1R/1S; Hfac– = 1,1,1,5,5,5-hexafluoroacetylacetonate ion) have been synthesized. They are characterized by single-crystal X-ray structure analysis (ССDС nos. 2124459 (1R) and 2124460 (1S)), elemental analysis, IR spectroscopy, thermogravimetric analysis and powder X-ray diffraction. Within their mononuclear molecular structure, the Dy(III) center locates in a coordination environment afforded by a 4R/4S-Pybox ligand and three Hfac− ions, displaying a nine-coordinated capped square antiprism coordination geometry with C4v symmetry. Solid circular dichroism spectrum further confirmed their enantiopure nature. Magnetic measurements indicated that 1R exhibits dual magnetic relaxation behavior, which was rarely observed in chiral SIMs family. The efficient energy barrier and relaxation time for the slow relaxation process are 6.85(4) K and 2.5 × 10−5 s, respectively.