1. Cobalt(II) and Nickel(II) Compounds with 2-Thiobarbituric Acid
- Author
-
N. M. Korotchenko and A. P. Lakeev
- Subjects
Aqueous solution ,medicine.diagnostic_test ,Chemistry ,Materials Science (miscellaneous) ,chemistry.chemical_element ,Protonation ,010402 general chemistry ,010403 inorganic & nuclear chemistry ,01 natural sciences ,0104 chemical sciences ,Ion ,Inorganic Chemistry ,Absorbance ,Nickel ,Spectrophotometry ,medicine ,Physical and Theoretical Chemistry ,Solubility ,Cobalt ,Nuclear chemistry - Abstract
Interaction between the systems containing cobalt(II) or nickel(II) chlorides and 2-thiobarbituric acid (C4H4N2O2S, H2L) was examined by spectrophotometry and pH-metry at pH < 4, I = 0.1 (NaCl) and T = 20°C. The compositions and the overall stability constants (log β11) of protonated complex species were determined: [CoHL]+ (3.69 ± 0.04), [NiHL]+ (3.68 ± 0.08), and [M(HL)2]. The compositions of the Co(C4H3N2O2S)2 · 4H2O and Ni(C4H3N2O2S)2 · 5H2O salts isolated from the studied systems were confirmed by different physicochemical methods; their solubility constants (log KS) were calculated to be –12.82 ± 0.22 and –12.30 ± 0.10, respectively. A spectrophotometric technique was developed for determining thiobarbiturate ion in aqueous solutions. This technique is based on the absorbance of iron(III) thiobarbiturate complex [FeL]+ and can be recommended for analytical chemists and pharmacists.
- Published
- 2020