The Structural and Magnetic Properties of Fe and Co Complexes with 2-(furan-2-yl)-5-pyridin-2-yl-1,3,4-oxadiazole.

Two novel coordination compounds containing heterocyclic bidentate ,-donor ligand 2-(furan-2-yl)-5-(pyridin-2-yl)-1,3,4-oxadiazole (fpo) were synthesized. A general formula for compounds originating from perchlorates of iron, cobalt, and fpo can be written as: M(fpo)(HO) (M = Fe(II) for () Co(II) for ()). The characterization of compounds was performed by general physico-chemical methods-elemental analysis (EA), Fourier transform infrared spectroscopy (FT-IR), nuclear magnetic resonance (NMR) in case of organics, and single crystal X-ray diffraction (sXRD). Moreover, magneto-chemical properties were studied employing measurements in static field (DC) for and X-band EPR (Electron paramagnetic resonance), direct current (DC), and alternating current (AC) magnetic measurements in case of . The analysis of DC magnetic properties revealed a high spin arrangement in , significant rhombicity for both complexes, and large magnetic anisotropy in ( = -21.2 cm). Moreover, showed field-induced slow relaxation of the magnetization ( = 65.3 K). EPR spectroscopy and ab initio calculations (CASSCF/NEVPT2) confirmed the presence of easy axis anisotropy and the importance of the second coordination sphere.