Crystal structures and physico-chemical properties of Zn(II) and Co(II) tetraaqua(3-nitro-4-hydroxybenzoato) complexes: Their anticonvulsant activities as well as related (5-nitrosalicylato)–metal complexes

Purposes of these studies were to synthesize Zn(II) and Co(II) complexes of 3-nitro-4-hydroxybenzoic acid, determine their structures through X-ray crystallography, and obtain their anticonvulsant activities. Thermogravimetric, differential scanning calorimetry, impedance of aqueous solutions and magnetic properties analyses were also determined. Anticonvulsant and related activities of these complexes as well as Zn(II), Co(II), Ni(II) and Mg(II) (5-nitrosalicylato) complexes were determined by the National Institutes of Health, Antiepileptic Development Program. Results of these analyses are presented to document unique bonding features and physical properties of these compounds and their anticonvulsant activities. It is concluded that these compounds have chemical and physical properties that can be used to account for their anticonvulsant activities.

Graphical abstractThe individual subunits of the (3-nitro-4-hydroxybenzoato) complexes of Zn(II) and Co(II) self-assemble via extensive hydrogen bonding involving water molecules leading to a 3D supramolecular architecture. The electrochemical impedance measurements show that these complexes are strong electrolytes in dilute aqueous solution. On the other hand, magnetic measurement of Co-complex indicates that the Co ions are ferromagnetically coupled. These complexes also show interesting anticonvulsant activities.Figure optionsDownload full-size imageDownload as PowerPoint slide