A new homobimetallic cobalt(II) complex based on the tetradentate 3,5-bis(2-pyridyl)-1H-1,2,4-triazole ligand: Synthesis, crystal structure, Hirshfeld analysis, spectroscopic characterization, magnetic properties and antimicrobial activities

A novel homobimetallic cobalt(II) complex, [Co-2(bpt)(2)(H2O)(4)](NO3)(2)center dot 2H(2)O (bpt = 3,5-bis(2-pyridyl)-1,2,4-triazolate), has been synthesized and characterized by single crystal X-ray diffraction, Hirshfeld surface analysis, as well as UV-Visible and FTIR techniques. The crystal structure determination shows that the dinuclear complex crystallizes in the triclinic crystal system with the P (1) over bar space group. The (N',N-1, N-2,N '')(2) double bridging coordination mode is realised with a distorted octahedral N4O2-coordinated cobalt centre. The structure cohesion is ensured by different intermolecular hydrogen bonds, pi-pi stacking interactions and intermolecular lone-pair center dot center dot center dot pi interactions. The structure consists of [Co-2(bpt)(2)](2)(+) dimeric units with a cobalt-cobalt distance of 4.170(2) angstrom. Magnetic measurements carried out on the homobimetallic complex indicate a relatively weak antiferromagnetic interaction between the two cobalt centres. This complex exhibited antimicrobial activity against several strains of the fungal phytopathogens Verticillium dahliae and Fusarium oxysporum fsp. melonis, as well as against the phytopathogenic bacteria Agrobacterium tumefaciens, suggesting its use in crop protection. (C) 2020 Elsevier Ltd. All rights reserved.