THE DIRECT ELECTROCHEMICAL SYNTHESIS OF SOME METAL DERIVATIVES OF LAPACHOL

The electrochemical oxidation of a sacrificial metal anode (M = Zn, Cd , Cu) in an acetonitrile solution of hydroxy-3-(3-methyl-2-butenyl)-1, 4-naphthoquinone, lapachol, C15H14O3(=HL) gives ML2. The results are i n keeping with earlier work on direct electrochemical synthesis in rel ated systems. Adducts with 2,2'-bipyridine (bpy) and N,N,N',N'-tetrame thylethanediamine (tmen) have also been prepared. The structure of the 2,2'-bipyridine adduct of Cu(lapacholate)(2) has been established by X-ray crystallography. The parameters are triclinic, space group P (1) over bar, a = 12.748(59) Angstrom, b = 13.859(49) Angstrom, c = 11.77 0(59) Angstrom, alpha = 108.30(4)degrees, beta = 108.08(3)degrees, gam ma = 68.94(3)degrees, Z = 2, R = 0.059 for 2256 unique reflections. Th e copper atom is ina distorted CuN2O2O2' environment. The mechanism of the formation of this Cu(lapacholate)(2) is discussed.