Synthesis, crystal structure, Hirshfeld surface analysis and DFT calculations of the coordination compound tetraaquabis{2-[(5-methyl-1,3,4-thiadiazol-2-yl)sulfanyl]acetato-κO}cobalt(II)

A novel coordination compound, [Co( L ) 2 (H 2 O) 4 ], was synthesized from aqueous solutions of Co(NO 3 ) 2 and the ligand 2-[(5-methyl-1,3,4-thiadiazol-2-yl)sulfanyl]acetic acid (H L , C 5 H 6 N 2 O 2 S 2 ). In the monoclinic crystals (space group P 2 1 / c ), the cobalt(II) ion is located about a centre of symmetry and is octahedrally coordinated by two L − anions in a monodentate fashion through carboxyl O atoms and by four water molecules. A relatively strong hydrogen bond between one of the water molecules and the non-coordinating carboxylate O atom consolidates the conformation. In the crystal, intermolecular hydrogen bonds lead to the formation of a complex tri-periodic structure. Hirshfeld surface analysis revealed that 30.1% of the intermolecular interactions are from H...H contacts and 20.8% are from N...H/H...N contacts. DFT calculations were performed to assess the stability and chemical reactivity of the compound by determining the energy differences between the HOMO and LUMO.