Hexacoordinated Co(ii) complex exhibiting strong magnetic anisotropy and field-induced slow magnetization relaxation: synthesis, magnetic characterization, and quantum-chemical modelling

Abstract

A hexacoordinated Co(II) complex of [CoL(NCS)₂]·2DMSO (1) composition, where L is tetradentate bis-quinolyl hydrazone 2,2′-(2,2′-(butane-2,3-diylidene)bis(hydrazin-1-yl-2-ylidene))diquinoline, has been synthesised and characterized by IR, SCXRD, and AC and DC magnetic measurements. Due to helix-like distortion of the complex, the Co(II) coordination polyhedron is distorted towards trigonal prismatic symmetry. Complex 1 demonstrates slow relaxation of magnetization in an applied DC magnetic field of 1000 Oe, which is well described by the Raman mechanism. The performed CASSCF+NEVPT2 calculations provide clear insight into the origin of the magnetic anisotropy in 1.