Investigation of the reaction of complex formation of Co(II) ions with N-(2-hydroxybenzoyl)-N'-(p-tosyl)hydrazine in ammonia medium

Abstract

A technique has been developed for the spectrophotometric determination of Co(II) ions with N-(2-hydroxybenzoyl)-N'-(p-tosyl)hydrazine (GBSH) in an ammonia medium. The absorption spectra of the reagent and its complex with Co(II) ions have been recorded and analyzed. The optimal conditions for the formation of the complex compound were found: the pH range of complex formation; optimal time for color development; amount of photometric reagent. Under optimal conditions for the complexation of GBSG with Co(Ⅱ) ions, a calibration graph was constructed. The Bouguer-Lambert-Beer law is fulfilled in the range from 0.3 to 2.4 mg Co(II) in 25 ml of solution. The true and apparent molar light absorption coefficients were calculated. The true molar coefficient of light absorption of the complex compound GBSG with Co(Ⅱ) ions in an ammonia medium is 750. The molar ratios in the solution of the complex compound [Co(Ⅱ)]:[GBSG] = 1:1 and 1:2. The conditional stability constant of the GBSG complex with Co(Ⅱ) ions was calculated using the Babko method and it is 3.24∙1012. The convergence and correctness of the spectrophotometric technique were determined by the method of mathematical statistics.