appropriately adjusted depending upon the nature of substrates and types of the apparatuses in the known manner the organometallic copper complex of the invention can be produced by reacting copper oxide i with an olefinic compound having a silylether or silylthioether group and a u03b2 diketone compound the resulting reaction mixture is then subjected to column chromatography according to the known method so that a desired product can be isolated otherwise the ligand exchange method in which a metal complex having a ligand which differs from the ligand of the desired complex is initially produced and subsequently the ligand of the produced metal complex is exchanged with an appropriate ligand to give the desired copper complex can be favorably employed in the latter method copper oxide i is first reacted with an olefinic compound having neither silylether group nor silylthioether group referred to as olefin a and a u03b2 diketone compound to obtain a reaction mixture containing a copper complex having as ligands olefin a and the u03b2 diketone compound the resulting copper complex is isolated by column chromatography in the known manner second the isolated copper complex is dissolved in an appropriate solvent to the resulting solution is added an olefinic.