Portal de Periódicos da CAPES

Determination of tetrahydroxycuprate and copper(II)-NTA complex stability constants by polarographic and spectrophotometric methods

1994; Elsevier BV; Volume: 13; Issue: 22 Linguagem: Inglês

10.1016/s0277-5387(00)83668-2

1873-3719

Eugenijus Norkus, A. Vaškelis,

Inorganic and Organometallic Chemistry

It was shown by the d.c. polarographic method that CuII ions form a tetrahydroxycuprate(II) complex Cu(OH)2−4 in alkaline solutions (1 mol dm−3 NaOH), and log βCu(OH)2−4 is 15.5±0.1, 14.1±0.3 and 13.7±0.07 (I = 3) at 20, 50 and 70°C, respectively. These data were confirmed by the spectrophotometric method. The complex CuX− (X3− = nitrilotriacetate anion, log β = 13.4±0.1) transforms to CuX(OH)2− (log β = 16.3±0.2) at pH > 10. It prevails at pH 10.6–12.7 and transforms to Cu(OH)2−4 at a higher alkalinity of the solution.