The Determination of The Stability Constants of Mixed Ligand Complexes of Creatinine L Cysteine and Creatinine L Cysteine Hydrocloride With Co II Cd II Zn II Mn II Using Potentiometric Method

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Karaderi S. , Bilğiç Alkaya D. , Cücü A.

Turkish Journal Pharm. Sci, vol.11, pp.33-44, 2014 (Refereed Journals of Other Institutions)

  • Publication Type: Article / Article
  • Volume: 11
  • Publication Date: 2014
  • Title of Journal : Turkish Journal Pharm. Sci
  • Page Numbers: pp.33-44


In this study, a potentiometric titration technique has been used to determine stability constants for

the various complexes of Zn(II), Co(II), Cd(II) and Mn(II) with creatinine and two amino acids. Stability

constants of ternary systems have been evaluated by the method suggested by Irving-Rossotti at 25°C and

0.11M ionic strength (kept constant with NaC104) in aqueous solution. In addition, the conditional constants

were calculated as a function of pH. The maximum values of the conditional formation constants

were found to be in accordance with the mixed-ligand complex formation constants in a given pH region.

In addition, the mole fractions of different species from mixed complexes were calculated by means of

formation constants. The values of stability constants of mixed-ligand complexes at 25°C were calculated

as follows: logK=3.20 for Zn(II)-L-cysteine-creatinine,logK1=4.24 and logK2=3.58 for Co(II)-L-cysteinecreatinine2,

logK=3.22 for Cd(II) - L-cysteine - creatinine, logK=3.65 for Mn(II) - L-cysteine - creatinine

and logK=5.34 for Co(II)-BDHL-cysteine-creatinine, logK=5.30 for Cd(II)-BDHL-cysteine-creatinine,

logK,=5.35 and logK =3.93 for Zn(II) - BDHL-cysteine - creatinine^, logK,=5.40 and logK =3.49 for

Mn(II) - BDHL-cysteine - creatinine,,