Synthesis and electrochemical study of 3- and 4-(2-pyridyl)-1,3- benzothiazole complexes with transition metals (Co^II, Ni ^II, and Cu^II). Molecular structure of bis{(4-(2-pyridyl)- 1,3-benzothiazole)copper(ii)} tetraacetate

A series of the M(L)Cl2 · nH2O and {M(L)}2(OAc)4 complexes (M = NiII, CoII, and CuII; L is 3- and 4-(2-pyridyl)-1,3-benzothiazole) were synthesized by the reaction of L with MX2 · nH2O (X = Cl, OAc) in ethanol. The molecular and crystal structures of the CuL2(OAc)4 binuclear complex (L is 4-(2-pyridyl)benzothiazole) were determined by X-ray diffraction analysis. The copper atoms have a distorted tetragonal bipyramidal environment and are coordinated to the nitrogen atom of the pyridine moiety of the ligand and to two oxygen atoms of the bridging acetate ligands. The Cu-Cu distance is 2.6129(9) Å. The electrochemical behavior of the synthesized ligands and complexes was studied using the cyclic voltammetry and rotating disk electrode techniques in DMF solutions (0.1 M Bu4NClO4). The primary reduction of all the complexes under study is directed to the metal.