Investigation of cobalt(Ⅱ) complexes with 4-(2-pyridyl)-amino-2,3- dimethylene-1-phenyl-5-pyrazlone using UV/VIS spectrophotometry

摘要

Investigation of Co(Ⅱ) complexes with 4-(2-pyridyl)-amino-2,3-dimethylene-1 -phenyl-5 -pyrazolone have been performed in solutions containing 10% methanol, at Constant temperature (25 ± 1)℃ and ionic strength of 0.5 mol dm~(-3) (NaNO_3) at pH = 6.34 (without buffer) and pH = 6.87 (with buffer), using the modified spectrophotometric methods of continuous variations and mole ratio. The composition and stability of the complexes have been obtained applying computerized iterations of succesive approximation to the theoretical equations. The complex has the stoichiometry Co(Ⅱ) : L = 1:2 and a relative stability constant of 7.05 ± 0.04. lieer's law was obeyed over the concentration range of 2.36-14.14μg cm~(-3) of cobalt(Ⅱ).