Two mononuclear single molecule magnets derived from dysprosium(iii) and tmphen (tmphen = 3,4,7,8-tetramethyl-1,10-phenanthroline)

Abstract

Two mononuclear Dy(III) complexes, [Dy^III(hfac)₃(tmphen)] (1) and [Dy^III(acac)₃(tmphen)]·2H₂O (2) (tmphen = 3,4,7,8-tetramethyl-1,10-phenanthroline, hfac = hexafluoroacetylacetone, acac = acetylacetone) have been synthesized and structurally characterized by single crystal X-ray diffraction. Magnetic properties indicate that both of the complexes exhibit SMM behavior, and complex 1 is the first typical derivative of phenanthroline containing D_2d-Dy(III) based mononuclear single molecule magnets. The energy barrier (U_eff/k_B) of complex 2 (130.42 K) is much higher than that of complex 1 (35.09 K), indicating that the local symmetry of Dy(III) ions (D_2d for 1, D_4d for 2) plays an important role in magnetic behaviors.