Ferromagnetic Oxime-Based Manganese(III) Single-Molecule Magnets with Dimethylformamide and Pyridine as Terminal Ligands

Abstract

Two new members of the [Mn6] family of single-molecule magnets (SMMs) of formulae [Mn6(μ3-O)2(H2N-sao)6(dmf)8](ClO4)2 (1) and [Mn6(μ3-O)2(H2N-sao)6(py)6(EtOH)2][ReO4]2·4EtOH (2), (dmf = N,N′-dimethylformamide, py = pyridine, H2N-saoH2 = salicylamidoxime) have been synthesized and characterized structurally and magnetically. Both compounds were straightforwardly prepared from the deprotonation of the H2N-saoH2 ligand in the presence of the desired manganese salt and solvent (dmf (1) vs. py (2)). Compound 1 crystallizes in the triclinic system with space group Pī and 2 crystallizes in the monoclinic system with space group P21/n. In the crystal packing of 1 and 2, the (ClO4)− (1) and [ReO4]− (2) anions sit between the cationic [Mn6]2+ units, which are H-bonded to –NH2 groups from the salicylamidoxime ligands. The study of the magnetic properties of 1 and 2 revealed ferromagnetic coupling between the MnIII metal ions and the occurrence of slow relaxation of the magnetization, which is a typical feature of single-molecule magnet behavior. The cationic nature of these [Mn6]2+ species suggests that they could be used as suitable building blocks for preparing new magnetic materials exhibiting additional functionalities.

Keywords

• manganese(III)
• salicylamidoxime
• molecular magnetism
• single-molecule magnets