Mixed-ligand complexes of copper (II) with ditiolfenols and heterocyclic diamines

By the methods spectrophotometric methods was investigated complex formation of copper with 2,6-ditiolphenol and its derivatives (2,6-ditiol-4-methylphenol, 2,6-ditiol-4-ethylphenol and 2,6-ditiol-4-tert-buthylphenol) in the presence of heterocyclic diamines. As heterocyclic diamines phenantroline (Fen), batophenantroline and dipyridile were used. It was established, that mixedligand complex were formed in weak acidic medium (pHop=6,0-8,5). Maximum of light absorption observed at (=522-550 nm. Molar coefficient of light absorption was ( = (3.08-4.92)?104. The stoichiometry of complexes had been discovered using shift the equilibrium and relative yield methods. During the extraction of copper(II) complexes with ditiol-phenols with the presence of heterocyclic diamines there was discovered that there is no chlorophorm molecules in the composition of the extracted complexes. IR spectra shows that hydroxyl group is involved to the formation of a bond with the metal and that phenantroline is included in the composition of the copper complex. In the organic phase mixed-ligand complexes have the monomeric form and can't polymerize; that fact can be proved by calculations. By dint of spectrophotometric, IR-spectroscopic, thermogravimetric experiments and some published data we were able to determine the structural formula of complexes. Also had been determined main spectrophotometric characteristics of copper(II) mixed-ligand complexes: pH of the beginning of the deposition, optimal pH, detection limit and sensivity. For separation and finding copper, we studied the effect of interfering foreign ions: alkali, alkaline earth and rare earth elements, as well as acid anions selected masking reagents. On the base of the results was offered photometric method for determination of copper in steel different trade-marks and in food. This method characterized by good reproduction (relatively standard deviation no more 0.05) and low limit of discovery.