Solvent Effects on Complexation of Molybdenum(VI) with Nitrilotriacetic Acid in Different Aqueous Solutions of Propanol

Abstract

By using spectrophotometric and potentiometric techniques the formation constants of the species formed in the systems H ＋ ＋Mo(VI)＋nitrilotriacetic acid and H ＋ ＋nitrilotriacetic acid have been determined in aqueous solutions of propanol at 25 ℃ and constant ionic strength 0.1 mol•dm -3 sodium perchlorate. The composition of the complex was determined by the continuous variation method. It was shown that molybdenum(VI) forms a mononuclear 1∶1 complex with nitrilotriacetic acid of the type MoO 3 L -3 at -lg[H ＋ ]＝5.8. The formation constants in various media were analyzed in terms of Kamlet and Taft's parameters. Linear relationships were observed when lg K S was plotted versus p*. Finally, the results were discussed in terms of the effect of solvent on complexation.

Complexation of Molybdenum(VI) with Ethylenediaminediacetic Acid in Different Water + Methanol Solutions

“…Our results are similar to the literature. 6 In contrast, complexation of molybdenum(VI) with NTA has also been studied in aqueous solutions of propanol, 16 but the parameter patterns 41,42 are different from the Gharib paper. 6 Another report in the literature 25 is about the solvent effects on the complexation of tungsten(VI) with EDDA in different aqueous solutions of propanol in which stability constants increase with increasing mole fractions of propanol.…”

“…Therefore, it is stated that the polarity of a solvent is determined by its solvation capability or (solvation power) for reactants and activated complexes as well as for molecules in their ground and excited states. , Thus, solvation power depends on all specific and nonspecific intermolecular forces between solvent and solute molecules which include Coulomb interactions between ions, directional interactions between dipoles, inductive, dispersion, hydrogen bonding, and charge-transfer forces, as well as solvophobic interactions. A literature survey reveals that in spite of several papers about thermodynamics and kinetics of solutions with different protic and aprotic solvents − there are no reports on the complexation of Mo(VI) with EDDA in different aqueous solutions of methanol. The present study deals with the aforementioned system, and the results have also been compared with similar complexes reported in the literature.…”

Complexation of molybdenum(VI) with methyliminodiacetic acid in different water + methanol solutions

“…[18][19][20][21] A literature survey showed that although there are only a few reports about the complexation of molybdenum(VI) with ethylenediamine-N,N′--diacetic acid (EDDA) in methanol-water 22,23 and complexation of tungsten(VI) 24 and molybdenum(VI) 25 with EDDA in propanol-water mixtures, no paper was found on stability constants data in different water + methanol solutions for the interaction of molybdenum(VI) with MIDA. It was seen from literature data [22][23][24][25] that the stability constants increased with decreasing polarity of alcohol-water mixtures, which confirms the pattern that was obtained in the current research. The concentration of Mo(VI) and MIDA and the kind of background electrolyte (c L = c M = 0.007 mol dm -3 , NaCl) in this research were different from that used in a previous work (c L = c M = 0.01 mol dm -3 , NaClO 4 ), 6 therefore the values of stability constants at 0 % methanol (I = 0.1 mol dm -3 ) in the two works were not the same (Table II).…”

Determination of Solvatochromic Regression Coefficients for the Molybdenum(VI) Complex with Ethylenediamine‐N,N′‐diacetic Acid by Using Kamlet‐Abboud‐Taft Equation

“…The other paper in the literature reports the order π*＞α＞β for the complexation of molybdenum(VI) with NTA in different aqueous solutions of propanol. 30 Complexation of tungsten(VI) with EDDA was studied in different aqueous solutions of propanol and the solvatochromic parameters are in the order of π*＞α＞β. 31 In our research KAT parameters are in the order of β＞π*＞α, which is similar to the literature.…”