Sonochemical synthesis of a new cobalt(II) complex: Crystal structure, thermal behavior, Hirshfeld surface analysis and its usage as precursor for preparation of CoO/CoO nanoparticles.

A bidentate Schiff base ligand and its nano-structured cobalt(II) complex were synthesized under ultrasound irradiation and then their structures were identified by physical and spectral techniques SEM and XRD techniques were used to confirm the nanostructure character of the complex. Single crystal X-ray diffraction analysis showed that the complex crystallizes in the triclinic system with space group of P1¯ and two crystallographically independent molecules participate in its asymmetric unit. In the structure of complex, cobalt center is four-coordinated by two iminic nitrogens of bidentate Schiff base ligand and two bromide anions in a distorted tetrahedral geometry. Crystal packing analysis well indicates that C-H⋯Br, C-H⋯π and π⋯π are the most intermolecular interactions. Moreover Hirshfeld surface analysis and 2D Fingerprint plots were applied for more investigation of intermolecular interactions. In addition, sonochemically prepared cobalt(II) bromide complex was subjected to calcination process under air atmosphere for preparation of cobalt oxide nanoparticles. The XRD pattern confirmed the simultaneous formation of CoO and CoO nanoparticles.