Cobalt(II) coordination complex with 2,5-bis(pyridine-2-yl)-1,3,4-thiadiazole and thiocyanate as co-ligand: Synthesis, crystal structure, Hirshfeld surface analysis, spectroscopic, thermal and magnetic properties

Abstract

The bis(2,5-di(pyridin-2-yl)-1,3,4-thiadiazole-κ2N,N′)-bis(thiocyanato-κ1N)cobalt(II) complex has been synthetized from the reaction of 2,5-bis(pyridin-2-yl)-1,3,4-thiadiazole (L) with metallic salt CoCl2.6H2O and thiocyanate ion (SCN−) as coligand in H2O/CH3CN at room temperature. The synthetized complex (CoL2(SCN)2) has been fully characterized by single crystal X-ray diffraction, Hirshfeld surface analysis, as well as UV–Visible, FTIR, Raman, and NMR spectroscopy. TGA analysis and magnetic measurements were also performed. CoL2(SCN)2 crystallizes in monoclinic symmetry and P 21/c space group with two independent cobalt crystallographic sites, where each cobalt atom is localized in a distorted octahedral environment CoN6, with the thiadiazole molecules (L) as bidentate ligands in equatorial sites and terminal SCN− ions in axial positions. The crystal cohesion is assured by intermolecular hydrogen bonding, C–H⋯π and π–π stacking; in addition to the N–Cu coordination bonds. This has been confirmed by the three dimensional Hirshfeld surface analysis and the two dimensional fingerprint plots that highlight the dominance of intermolecular interactions C⋯H/H⋯C and S⋯H/H⋯S. The thermal analysis of CoL2(SCN)2 reveals that this complex is thermally stable up to 200 °C. Variable-temperature magnetic susceptibility measurements on CoL2(SCN)2 complex indicated an antiferromagnetic exchange between the two non-equivalent cobalt(II) ions with a ferrimagnetic behaviour.