Two Types of {FeDy} Heterometallic Complexes Containing Fe4 Structure: Carboxylate Derivatives Effect on the Structures and Magnetic Properties

Abstract

We successfully obtained two type of heterometallic complexes [Fe4Dy2(L1)2(µ4-O)2(piv)4(H2O)2(NO3)4]·CH3CN·CH3OH (1) and [Fe6Dy2(L1)2(µ4-O)2(CH3COO)6(OH)2(H2O)2(NO3)6]·CH3CN (2) by using 2,2′-((2-((2-hydroxyethyl)amino)cyclohexyl)azanediyl)bis(ethan-1-ol) (H3L1), Dy(NO3)3·6H2O, FeCl3 and pivalic acid (piv) or acetic acid under room temperature in different solvent. Crystal structure showed that the central structure of [ $${{\text{Fe}}}_{4}^{{\text{III}}}$$ (µ4-O)2]8+ arranged in what was often termed an absent cubic shape, although here the Fe centers were strictly coplanar. Each Fe3 triangle was connected to the capping Dy(III) through µ4-O bridges for complex 1, and each Fe3 triangle was connected to the capping Fe(III) through µ4-O bridges for complex 2. It might be due to the steric effect that the coordination atoms of piv ligands chelated and blocked the structure. AC magnetic susceptibilities exhibited that complex 1 and 2 showed out-of-phase (χ″) component of ac-susceptibilities at zero Oe static magnetic field over the frequency range of 9–999 Hz, which energy barriers were 0.44 and 0.13 K. And their energy barriers were 1.2 and 12.2 K at applied 1000 Oe static magnetic field.