Six-coordinate Ln(III) complexes with various coordination geometries showing distinct magnetic properties

Abstract

The syntheses, structural characterization, and magnetic properties of three lanthanide complexes with formulas [Ln(L1)3] (Ln = Dy (1Dy); Er (1Er)); and [Dy(L2)2] (2Dy) were reported. Complexes 1Dy and 1Er are isostructural with the metal ion in distorted trigonal-prismatic coordination geometry, but exhibit distinct magnetic properties due to the different shapes of electron density for DyIII (oblate) and ErIII (prolate) ions. Complex 1Dy shows obvious SMM behavior under a zero direct current (dc) field with an effective energy barrier of 31.4 K, while complex 1Er only features SMM behavior under a 400 Oe external field with an effective energy barrier of 23.96 K. In stark contrast, complex 2Dy with the octahedral geometry only exhibits the frequency dependence of alternating current (ac) susceptibility signals without Χ" peaks under a zero dc field.