New Cobalt(II) and Copper(II) Thiocyanate Complexes of 2,5‐Bis(pyridin‐2‐yl)‐1,3,4‐oxadiazole Ligand: Synthesis, Crystal Structures, Spectral Properties and Hirshfeld Surface Analysis

Abstract

AbstractThe synthesis and characterization of two new mononuclear coordination complexes based on 2,5‐bis(pyridin‐2‐yl)‐1,3,4‐oxadiazole (bpox) and thiocyanate ion as coligand, [M(bpox)2(SCN)2]nH2O (M=Co, n=1 for complex 1; M=Cu, n=0 for complex 2), are described. The obtained complexes crystallize in the monoclinic crystal system with space group C 2/c for complex 1 and P 21/n for complex 2. UV/Vis, FTIR and Raman data indicated the presence of bpox and thiocyanate groups, in isolated compounds. This finding has been confirmed by crystallographic studies, which shows that the two metals Co(II) and Cu(II), have an octahedral environment in complex 1 and complex 2, respectively, with both bpox ligands in equatorial sites and terminal SCN− in axial positions. The crystal structure cohesion of each compound is ensured by intramolecular metal‐nitrogen M–N (M= Co, Cu) interactions, by π–π stacking interactions and by different intermolecular‐hydrogen bonds, such as C–H⋯π, O–H⋯N, O–H⋯O, C–H⋯N, and/or C–H⋯S. The three‐dimensional Hirshfeld surface analysis and the two‐dimensional fingerprint plots reveal that the structure is dominated by C⋯H/H⋯C contacts.