Synthesis, crystal structure and magnetic properties of a pentanuclear Mn(III) cluster with 1,2,4-triazole based Schiff base ligand

Abstract

The reaction of equimolar amounts of 2-hydroxy-5-iodobenzaldehyde and 5-(methylthio)-1H-1,2,4-triazol-3-amine in methanol yielded a new 1,2,4-triazole based Schiff base ligand, H2L, which was characterised by spectroscopic methods. The combination of this Schiff base ligand with Mn(OAc)2·4H2O and KSCN in methanol yielded dark brown crystals of [KMn5(L)4(O)2(OAc)4(CH3OH)2(H2O)]·5.25(CH3OH)·2.33(H2O) (1), which were characterised by elemental analysis, spectroscopic methods and single-crystal X-ray diffraction. The compound contains Mn(III) pentanuclear clusters in which two oxido, four acetate and four dinegative Schiff base ligands link the Mn(III) ions. The structure of the cluster consists of two perpendicular Mn3O units and one Mn(III) ion acting as a bridge between them. The study of the magnetic properties revealed the occurrence of antiferromagnetic intramolecular interactions among the Mn(III) atoms. Since this type of compounds are candidates to exhibit SMM-behavior, the presence of SMM behavior is also investigated.