Experimental and in silico studies of dichloro-tetrakis(1H-pyrazole)-cobalt(II): Structural description, photoluminescent behavior and molecular docking

Abstract

A novel pyrazole-based Co(II) complex, namely dichloro-tetrakis(1H-pyrazole)-cobalt(II), was synthesized and characterized. Its X-ray crystal structure showed that it crystallizes in the monoclinic C2/c space group with discrete [CoPz4Cl2] units held together via intra- and intermolecular hydrogen bonds. The non-covalent interactions were explicitly analyzed by means of the topological and Hirshfeld surface analyses, revealing the presence of 0-periodic binodal 1,6-connected 1,6M7–1 and 14-connected uninodal bcu–x topologies built up through N—H…Cl and C—H…Cl hydrogen-bonding networks in addition to weak non-classical H…H, NH…C, CH…N, N—H…π, π…lp/lp…π and lp…lp interactions. Additionally, interactions energy and energy frameworks analyses were performed in order to compute the total energies of the possible intermolecular interactions. The empty space in the crystal lattice was analyzed using void mapping which lead to the presence of small cavities. The structure was furthermore optimized showing a very good agreement with the experimental results, the molecular electrostatic potential (MEP) maps were obtained with their active regions and the non-linear optical properties estimated. Additionally, the optical properties of the title complex were investigated at room temperature using optical UV-visible absorption and photoluminescence spectroscopy, exhibiting π → π*, n → π*, d → d and ligand-field transitions which result in a large variety of emission bands predominant by a bright red photoluminescence. An in silico study was carried out and the binding ability of the title complex with Staphylococcus aureus tyrosyl-tRNA synthetase and Pyrococcus kodakaraensis aspartyl-tRNA synthetase was evaluated displaying a good inhibition activity towards the last one.