Stability Constants of Dioxy Vanadium(V)-Glycylglycine System and a Related Calculating Model

Document Type : Research Paper




In this research some mathematical calculations has been explained on the “ +
VO2 +
glycylglycine” system and some equations has been deduced to determine the stability constants of
the equilibrium models including MLH+, ML and ML2H species (while M+ ≡ +
2 VO , H2L+ ≡
protonated glycylglycine and MLH+, ML and ML2H represent the considered complexes). The
calculations are based on some relations between variation of absorbance (in the UV-vis region)
and hydrogen ion concentration. The absorptivities and stability constants of complexes could be
obtained from the intercept and slope of resulting linear equations. According to this approach the
complexes refer to “ +
VO2 + glycylglycine” system has been investigated in aqueous solutions at
ionic strength 0.5mol dm-3 sodium perchlorate at 250C ( ± 0.1); and a combination of
potentiometric and spectrophotometric (UV-vis) method was used.