Studies on Cobalt(II) Complexes with Benzenesulfonate: Synthesis, Crystal Structure, and Spectroscopic and Magnetic Properties

Two novel transition metal benzenesulfonate complexes with a formula [Co(H2O)6][C7H5O3SO3]2⋅2H2O (1) and Na4[Co(H2O)2 Cl4][C7H5O3SO3]2⋅4H2O (2), have been synthesized and characterized by single-crystal X-ray diffraction technique; thermal analysis was done and spectroscopic and magnetic properties were studied. The [Co(H2O)6][C7H5O3SO3]2⋅2H2O (1) complex crystallizes in the triclinic system; however, the (2) complex crystallizes in the monoclinic crystal system with the C2/c space group. Each Co(II) atom in (1) and (2) is octahedrally coordinated. A hydrogen bond links the complex cation and anion, forming one-dimensional hydrogen-bonded supramolecular chains. The complexes exhibit different decomposition characteristics. Magnetic susceptibility measurement shows that complexes have weak anti-ferromagnetic intermolecular interactions between many local spins. The magnitude and nature of these magnetic interactions are discussed in the light of their respective structures, and they are compared with those reported for related systems. Magnetic moments of both compounds at room temperature are characteristic of high-spin complexes Co(II).