Spectrophotometric Investigation of the Reaction of Cu(II) Ions with N-Benzoyl-N'-(phenylsulphonyl)hydrazine in Ammonia Media

Abstract

We investigated the complexation reaction of N-benzoyl-N'-(phenylsulfonyl)hydrazine with Cu(II) ions in an ammonia medium. The absorption spectra of the reagent and its complex compound with Cu(II) ions were recorded and analyzed. Optimal conditions for complex formation were determined, including the pH range for complexation, the optimal time for color development, and the amount of photometric reagent. Under optimal conditions, a calibration curve for the complexation of BFSH with Cu(II) ions was plotted. The Beer–Lambert–Bouguer law is valid in the range from 0.5 to 1.75 mg of Cu(II) in 25 mL of the solution. The true (19 389 cm²/mol) and apparent (4708 cm²/mol) molar absorption coefficients were calculated. Using the methods of saturation, equilibrium shift, curve intersection, isomolar series, and conductometric titration, the molar ratios in the solution of the complex compound were determined as [Cu(II)] : [BFSH] = 1 : 1 and 1 : 2. The conditional stability constant of the complex, calculated using the Babko method, is 2.45 × 10¹³. The convergence and accuracy of the spectrophotometric method were determined statistically.