Synthés et caractérisation d'un sel à Anion complexe Hétéroleptique de cuivrel(II) à base des Lig and Oxalato (C2O4)2 et Tartrato(C4H4O6)2-

Abstract

In this work, the heteroleptic complex of tartrato oxalato copper(II)hexahydrate K6[Cu2(C2O4)4(C4H4O6)]•6H2O coded « Kcuoxtart » was synyhesised at a temperatures of about at 70 °C, by the reaction between hydrated copper(II) dichloride (CuCl2•2H2O), monohydratedipotassiumoxalate (K2C2O4•H2), and tetrahydrate dipotassiumtartrate (K2C4H4O6•4H2O) in the ratio 2 :4 :1. The monocristal with a blue color was obtained with a yield of 67.6 % after slow evaporation of the solvent at room temperature in fumecupboard for a period of 2 weeks. It was then subjected to different technical characteristic. Solubility tests has show that « Kcuoxtart » was not soluble in pure methanol, partially soluble in ethanol, water and in mixture of these solvents. And it was soluble in water. Analytic test proved the presence of K+ and Cu2+ ions in this material. Infrared spectroscopic studies show different signals indicating the presence of an oxalato (C2O42-) and tartrato (C4H4O62-) ligands, with existence of a water of crystallization molecule (H2O) and the presence of the coordination bonds Cu-O and K-O respectively at 538 and 470 cm-1, hence evidence show that a coordination complex was obtain. Meanwhile ultra-violet studies showed a transition in the visible zone around 700 nm which is characteristics of ad-d transition of Cu2+ ion, confirming the colours of the singles crystals of « Kcuoxtart ». Molar conductance studies indicated an ionic character of « Kcuoxtart » and showed that contained more than 5 ions in solution equivalent to a total of seven (07) ions 6 K+ and 1 [Cu2(C2O4)4(C4H4O6)]6-. Evaluation of the number of molecules of water of cristallization in this material « Kcuoxtart » proved that this compound contains six (06) molecules of water of cristallization. Hence the formular K6[Cu2(C2O4)4(C4H4O6)]•6H2O, and the crystal structure should be determined by X-ray diffraction on singles crystals for a clear confirmation .