Complexation of Dioxovanadium(V) with D-(-)-Quinic Acid at Different Ionic Strengths Using Different Models Based on the Debye-Hückel Theory

Abstract

The complex formation reaction between the dioxovanadium(V) cation VO + 2 and D-(-)-quinic acid {(1R,3R,4S,5R)-(-)-1,3,4,5-tetrahydroxycyclohexane-1-carboxylic acid} has been studied in aqueous solutions. The UV data and the values of the derived conditional stability constants are presented and discussed in the light of one stoichiometric model for the reaction at T = 298 K and different ionic strengths (0.10 to 1.00) mol·dm −3 of sodium chloride. Speciation diagrams and dissociation constants were obtained on the basis of UV spectroscopic measurements and potentiometric titrations, respectively. Our results show that one complex species, VO 2 L, exists in solution in the pH range of about 1.00 to 3.00. The parabolic, Specific Ion Interaction Theory (SIT), and extended Debye-Hückel type (EDH) models successfully describe the ionic strength dependence of the stability constants. A comparison with literature data is also reported.

Calculation of the stability constants for the complex formation of dioxovanadium (V) with methyliminodiacetic acid in various H2O + CH3OH solutions using kamlet-abboud-taft equation

“…3 Vanadium plays a catalytic role in metalloenzyme systems, such as nitrogenase and haloperoxi-dases. 9 Isopolyvanadates should not be present, therefore the solution was left overnight before use in order to obtain only the VO 2 + . 5 In the present study, the aim was to clarify the role of various specific and nonspecific interactions in solution by application of the KAT equation, similarly to previous reports concerning the complexation of dioxovanadium(V) and molybdenum(VI) with ethylene glycol bis(2-aminoethyl ether)--N,N,N΄,N´-tetraacetic acid (EGTA) and ethylenediamine-N,N΄-diacetic acid (EDDA).…”