Magnetic exchange effects in {CrIII2DyIII2} single molecule magnets containing alcoholamine ligands

Abstract

The synthesis and magnetic characterisation of four new heterometallic {CrIII2DyIII2} complexes 2-5 are described. The present work follows on from a recently isolated complex [CrIII2DyIII2(OMe)2(O2CPh)4(mdea)2(NO3)2] (1) (mdeaH2 = N-methyldiethanolamine), which displayed impressive single molecule magnet (SMM) properties, notably highly coercive magnetic hysteresis loops below 3.5 K. Compounds 1-5 all display a planar butterfly type metallic core arrangement, with the DyIII ions occupying the central body positions and the CrIII ion the outer wing positions. The core is stabilized by the amine-diolate, and carboxylate bridging ligands. Variation of the amine-diolate ligand resulted in sever..