Complexes of Co(II), Ni(II) and Cu(II) with lapachol

Abstract

Complexes of naturally occurring hydroxynaphtho-quinone, lapachol (2-hydroxy-3(3-methyl-2-buthenyl)-1,4-naphthoquinone = HL) with Co(II), Ni(II) and Cu(II) have been prepared by reaction of the corresponding acetates with the ligand (HL) in ethanol. The molecular and crystal structures were determined for [CoL 2(EtOH) 2] ( 1), [NiL 2(EtOH) 2] ( 2), and [CuL 2(py) 2] ( 3). In all cases the deprotonated lapachol behaves as chelating bidentate ligand. The complexes were also characterized by elemental analyses, cyclic voltammetry, and FAB-MS.