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The synthesis and characterization of two new mononuclear coordination complexes based on 2,5-bis(pyridin-2-yl)-1,3,4oxadiazole (bpox) and thiocyanate ion as coligand, [M (bpox) 2 (SCN) 2 ]nH 2 O (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 2 1 /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 À 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 intermolecularhydrogen 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.[a] Dr.

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Reaction of 2,4-pentanedione with thiosemicarbazide in 1:2 ratio produces cyclic pyrazoline thiosemicarbazone (H 2 L 2 with L 2 = C 7 H 12 N 6 S 2 ). The obtained ligand has been characterized by elemental analysis, UV-Visible, FTIR, 1 H and 13 C NMR. The results suggest that the ligand is in pyrazolinic form, and finally the structure has been confirmed by single crystal X-ray diffraction.The [(L 2• )Cu(SCN)] copper complex has been prepared by reaction of H 2 L 2 and thiocyanate salt with copper acetates and has been fully characterized by single crystal X-ray diffraction, Hirshfeld surface analysis, as well as UV-Visible, FTIR, and Raman spectroscopies. TGA analysis and magnetic measurements were also performed. Single-crystal X-ray diffraction reveals that the complex is a neutral monomer with copper in distorted tetrahedral environment. The anionic ligand (L 2• )remained in cyclic form and is coordinated as terdentate ligand (SNS). The title complex results from a double deprotonation coupled with a monoelectronic oxidation of H 2 L 2 and it may be seen as a Cu II -ligand radical type complex. The copper ion is tetra coordinated (CuN 2 S 2 ) by two sulfur and one nitrogen of (L 2• )and by thiocyanate nitrogen atoms. The new [(L 2• )Cu(SCN)] complex crystallizes in the monoclinic system and C 2/c space group. Full-Potential Linearized Augmented Planewave Method (FLAPW) calculations based on the Density-Functional Theory (DFT) principle are performed to shed light on both electronic and magnetic structures as well.[(L 2• )Cu(SCN)] showed a greater activity than its parental ligand H 2 L 2 against two strains of the phytopathogenic fungus Verticillium dahliae while a moderate antibacterial activity was recorded with both against Agrobacterium tumefaciens strains and Pseudomonas syringae pv. syringae.

The reaction of 2,5-bis(pyridin-4-yl)-1,3,4-oxadiazole (4-pox) and thiocyanate ions, used as co-ligand with nickel salt NiCl2·6H2O, produced the title complex, [Ni(NCS)2(C12H8N4O)2(H2O)2]. The NiII atom is located on an inversion centre and is octahedrally coordinated by four N atoms from two ligands and two pseudohalide ions, forming the equatorial plane. The axial positions are occupied by two O atoms of coordinated water molecules. In the crystal, the molecules are linked into a three-dimensional network through strong O—H...N hydrogen bonds. Hirshfeld surface analysis was used to investigate the intermolecular interactions in the crystal packing.