Coordination compounds of chromium(III) with different complexones and citric acid in aqueous solutions

A spectrophotometric study of heteroligand chromium(III) complexes with iminodiacetic (H₂Ida), N-methyliminodiacetic (H₂Mida), N-(-hydroxyethyl)iminodiacetic (H₂Heida), nitrilotriacetic (H₃Nta), ethylenediaminetetraacetic (H₄Edta), and citric acids (H₄Cit) showed that complexation in ternary systems depends on the concentrations of the reagents and the pH of the medium. The resulting complexes were Cr(HIda)(H₂Cit)], Cr(HMida)(H₂Cit)], Cr(HHeida)(H₂Cit)], Cr(HHeida)(HCit)]^–, Cr(HNta)(H₂Cit)]^–, Cr(HNta)(HCit)]^2–, Cr(Nta)(HCit)]^3–, Cr(HEdta)(HCit)]^3–, and Cr(Edta)(HCit)]^4–. The logarithms of their stability constants are 41.97 ± 0.47, 43.54 ± 0.62, 42.32 ± 0.62, 36.34 ± 0.26, 43.70 ± 0.25, 39.75 ± 0.45, 32.93 ± 1.56, 46.46 ± 0.80, and 41.71 ± 0.81 , respectively (I = 0.1 (NaClO ₄)).Translated from Koordinatsionnaya Khimiya, Vol. 30, No. 12, 2004, pp. 946–950.Original Russian Text Copyright © 2004 by Kornev, Mikryukova.