A SPECTROPHOTOMETRIC STUDY OF THE FORMATION OF NICKEL(II) ION COMPLEXES WITH CEFACLOR

The formation of Ni(II) ion complexes with cefaclor has been investiga ted by ultraviolet spectroscopy. This study has shown that cefaclor an d Ni2+ interact in weak acidic medium to give a Ni(CEF)(+) complex whi ch easily hydrolyzes giving a hydroxo complex Ni(OH)(CEF). This comple x species at pH = 8.70 shows absorption bands in the range from 400 to 294 nm, with a maximum at 316 nm. Using the Job method, the molar rat ios method and the method of relative recovery of complex species the stoichiometric ratio cefaclor : Ni(II) = 1:1 was found. The molar abso rptivity value, epsilon = 1.12 +/-0.02 x 10(3) l mol(-1) cm(-1) at 316 nn and the concentration constant of the hydroxo complex log K-2 = 8. 3 +/- 0.1 l/mol, were determined at pH = 8.70 and at an ionic strength of mu = 0.01.