Five mixed-chelate copper(II) complexes with the general formula [Cu(acac)(diam)]ClO4, where acac is acetylacetonate ion and diam is N,N0-dibenzylic or thiophene derivatives of ethylenediamine were prepared and characterized by elemental analysis, spectroscopic and conductance measurements. The X-ray crystal analysis of these complexes demonstrated that ClOK4 ions are bound weakly above and below of the chelate plane. In solution, the perchlorate ions are driven out by solvent molecules leading to their solvatochromism.
