Unexpected CuIIZnII amine–imine complex obtained by template reaction under “direct synthesis” conditions

Copper powder reacts with zinc oxide, ammonium chloride, ethylenediamine and methyl ethyl ketone in methanol solution to afford a bimetallic complex with the open chain diaminodiaza ligand – 4,5-dimethyl-1,9-diamino-3,7-di-aza-nona-3-ene (L1) containing the –CH2–CH(CH3)–C(CH3)double bond; length as m-dash bridge linking the amine residues. The origin of the bridge was shown to be a result of template condensation of methyl ethyl ketone and formaldehyde arisen in the process of oxidation of methanol over copper powder acting in the reaction as both a source of metal and a catalyst. The crystal structure of Cu(L1)ZnCl4 was determined by X-ray diffraction and represents the first example of L1 to be crystallographically characterized.