Zusammensetzung und Stabilität von Komplexen des Kupfer(II)-Ions mit DL-Threonin in Lösung

The equilibria in Cu(II) ion and DL-threonine (ThrH₂) solutions have been studied. It was found that in the pH interval from 2 to 13.5 the following compounds can exist: CuThrH⁺, Cu(ThrH), Cu(Thr)(ThrH)^? and Cu(Thr). The stoichiometric instability constants of the first two compounds were determined by the spectrophotometric method and by a combination of spectrophotometric and potentiometric methods. In addition, it was established in the same way that the Cu(ThrH) complex behaves like a weak dibasic acid, whose ionisation constants were determined too. Finally, the absorptionspectra of the above complex compounds are given.