Determination of Characteristic Constants of Nickel and Manganese Complexes with p-Nitro-o-carboxylazo-chromotropic Acid

Abstract

The synthesis of the novel ligand, p-nitro-o-carboxylazo-chromotropic
acid (NCBAC) was carried out and it can react with nickel and manganese
at pH 9.6. The updated determination of the properties of the complexes
was carried out by the spectral correction method instead of ordinary
spectrophotometry. The stepwise real absorptivity (ε) and the cumulative
stability constant (K) of Ni-NCBAC and Mn-NCBAC complexes was
obtained easily. Results showed that the composition ratios of the complexes
were Ni : NCBAC = 1 : 1 and Mn : NCBAC = 4 : 1, their cumula-
live K 3.57 x 10⁵ and 1.2 x 10⁵ and their  ε  1.76 x 10⁴ and 4.49 x 10³ L
mol^-1 cm^-1 respectively at 580 nm.