The synthesis and characterization of the binary complex of copper(II) with the antiepileptic drug valproic acid sodium salt (Valp) and the related ternary complex with 1,10-phenanthroline (phen) are reported, as well as the anticonvulsant properties of the latter. The characterization was carried out by means of elemental analyses, infrared (IR), UV-visible (UV-vis) spectrophotometry and Electron Paramagnetic Resonance (EPR). The X-ray crystal structure of the mononuclear complex bis(2-propylpentanoate)(1,10-phenanthroline)copper(II) [Cu(Valp)(2)phen] is showed for the first time. It crystallized in C2/c space group with unit cell dimensions of a = 14.939(1) A, b = 19.280(1) A, c = 9.726(1) A, beta = 97.27(2) degrees , V = 2778.8(4) A(3) and Z = 8. The carboxylates bond in an asymmetric chelating mode and the copper atom adopts a highly distorted octahedral coordination, characterized by the sum of the angles of 365.9 degrees around Cu(II) and its nearest atoms in the CuN(2)O(2) + O(2) chromophore instead of the expected 360 degrees for a basal square planar geometry found in most Cu(II) complexes. Molecules assemble three by three through slipped pi-pi stacking of the aromatic phen with respectively 3.519 and 3.527 A distances, in a head-to-tail arrangement. Studies of the anticonvulsant properties of this bioligand chelate evidenced its lack of efficacy in preventing MES-induced seizures. Interestingly, complex 4 protected mice against the Minimal Clonic seizures at doses that do not cause Rotorod toxicity, with an ED(50) documenting very potent anticonvulsant activity in this model of seizure, a particularly useful pharmacological profile of activity for the treatment of Petit Mal seizures.