Thermodynamic Complexation of Dopamine with Molybdenum(VI) in Media with Different Dielectric Constants

Bagheri, A.

doi:10.1021/je9001619

Cited by 5 publications

(5 citation statements)

References 25 publications

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“…In this light, we selected the systems listed in Table 16, which reports the stability of the complexes determined at similar experimental conditions. By using the protonation constants proposed in those literature papers [44,45,[48][49][50][51][52][53] and adding to the speciation models, the hydrolytic constants of the metals, taken from Brown and Edberg [54], the pL 0.5 values were calculated at T = 298.15K, I = 0.2 mol dm −3 and pH = 7.4. The obtained values reported in Figure 15, can be compared with the values here presented for our systems.…”

Section: Literature Datamentioning

confidence: 99%

The Solution Behavior of Dopamine in the Presence of Mono and Divalent Cations: A Thermodynamic Investigation in Different Experimental Conditions

et al. 2021

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The interactions of dopamine [2-(3,4-Dihydroxyphenyl)ethylamine, (Dop-)] with methylmercury(II) (CH3Hg+), magnesium(II), calcium(II), and tin(II) were studied in NaCl(aq) at different ionic strengths and temperatures. Different speciation models were obtained, mainly characterized by mononuclear species. Only for Sn2+ we observed the formation of binuclear complexes (M2L2 and M2LOH (charge omitted for simplicity); M = Sn2+, L = Dop−). For CH3Hg+, the speciation model reported the ternary MLCl (M = CH3Hg+) complex. The dependence on the ionic strength of complex formation constants was modeled by using both an extended Debye–Hückel equation that included the Van’t Hoff term for the calculation of enthalpy change values of the formation and the Specific Ion Interaction Theory (SIT). The results highlighted that, in general, the entropy is the driving force of the process. The sequestering ability of dopamine towards the investigated cations was evaluated using the calculation of pL0.5 parameter. The sequestering ability trend resulted to be: Sn2+ > CH3Hg+ > Ca2+ > Mg2+. For example, at I = 0.15 mol dm−3, T = 298.15 K and pH = 7.4, pL0.5 = 3.46, 2.63, 1.15, and 2.27 for Sn2+, CH3Hg+, Ca2+ and Mg2+ (pH = 9.5 for Mg2+), respectively. For the Ca2+/Dop- system, the precipitates collected at the end of the potentiometric titrations were analyzed by thermogravimetry (TGA). The thermogravimetric calculations highlighted the formation of solid with stoichiometry dependent on the different metal:ligand ratios and concentrations of the starting solutions.

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Section: Literature Datamentioning

confidence: 99%

The Solution Behavior of Dopamine in the Presence of Mono and Divalent Cations: A Thermodynamic Investigation in Different Experimental Conditions

et al. 2021

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“…Furthermore, the difficulties in comparing the results reported in the different papers are also related to some other factors, such as the neglecting of the effect of metal hydrolysis on the speciation of the metal-dopamine system, or the consideration dopamine as diprotic rather than a triprotic ligand [31][32][33][34]46,[52][53][54][55][56][57][58][59].…”

Section: Literature Datamentioning

confidence: 99%

The Effect of Metal Cations on the Aqueous Behavior of Dopamine. Thermodynamic Investigation of the Binary and Ternary Interactions with Cd2+, Cu2+ and UO22+ in NaCl at Different Ionic Strengths and Temperatures

et al. 2021

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The interactions of dopamine [2-(3,4-Dihydroxyphenyl)ethylamine, (Dop−)] with cadmium(II), copper(II) and uranyl(VI) were studied in NaCl(aq) at different ionic strengths (0 ≤ I/mol dm−3 ≤ 1.0) and temperatures (288.15 ≤ T/K ≤ 318.15). From the elaboration of the experimental data, it was found that the speciation models are featured by species of different stoichiometry and stability. In particular for cadmium, the formation of only MLH, ML and ML2 (M = Cd2+; L = dopamine) species was obtained. For uranyl(VI) (UO22+), the speciation scheme is influenced by the use of UO2(acetate)2 salt as a chemical; in this case, the formation of ML2, MLOH and the ternary MLAc (Ac = acetate) species in a wide pH range was observed. The most complex speciation model was obtained for the interaction of Cu2+ with dopamine; in this case we observed the formation of the following species: ML2, M2L, M2L2, M2L2(OH)2, M2LOH and ML2OH. These speciation models were determined at each ionic strength and temperature investigated. As a further contribution to this kind of investigation, the ternary interactions of dopamine with UO22+/Cd2+ and UO22+/Cu2+ were investigated at I = 0.15 mol dm−3 and T = 298.15K. These systems have different speciation models, with the MM’L and M2M’L2OH [M = UO22+; M’ = Cd2+ or Cu2+, L = dopamine] common species; the species of the mixed Cd2+ containing system have a higher stability with respect the Cu2+ containing one. The dependence on the ionic strength of complex formation constants was modelled by using both an extended Debye–Hückel equation that included the Van’t Hoff term for the calculation of the formation enthalpy change values and the Specific Ion Interaction Theory (SIT). The results highlighted that, in general, the entropy is the driving force of the process. The quantification of the effective sequestering ability of dopamine towards the studied cations was evaluated by using a Boltzmann-type equation and the calculation of pL0.5 parameter. The sequestering ability was quantified at different ionic strengths, temperatures and pHs, and this resulted, in general, that the pL0.5 trend was always: UO22+ > Cu2+ > Cd2+.

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“…In the literature there are several papers containing information on the acid–base properties of dopamine and its ability to form complexes with metal ions. ,,,,− ,,,− , However, until now this information appeared quite confusing, probably because of the difficulty in determining the protonation constants of all the equilibrium steps. Another important problem is bound to the uncertainty of the association of the log K i H values to the correct functional groups.…”

Section: Literature Comparisonmentioning

confidence: 99%

“…Dopamine [2-(3,4-dihydroxyphenyl)ethylamine] (see Scheme ) is an important neurotransmitter that plays a fundamental role in the regulation of hormonal secretions in the central nervous system and in the peripheral organs implicated in the control of motor\cognitive and neuroendocrine functions. Its improper regulation is associated with neurological diseases such as parkinsonism, where dopamine levels are reduced, and schizophrenia, which can be related to excess dopamine activity. − …”

Section: Introductionmentioning

confidence: 99%

“…It is a precursor of adrenaline and forms in adrenergic nerve endings [tyrosine →3,4-dihydroxy-phenylalanine → dopamine → noradrenaline → adrenaline]. Owing to the presence in the molecule of three donor centers (two phenolic and one amino groups), it can form chelate complexes with metals of biological interest. − Many biochemical processes that occur in living organisms involve the stages related to a change in the hydration (solvation) state of biomolecules participating in the chemical interaction. The solvation environment plays a considerable role in the complex multistage process of molecular recognition and fixation of physiologically active substances on receptor targets.…”

Section: Introductionmentioning

confidence: 99%

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Thermodynamic Properties of Dopamine in Aqueous Solution. Acid–Base Properties, Distribution, and Activity Coefficients in NaCl Aqueous Solutions at Different Ionic Strengths and Temperatures

et al. 2013

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The acid–base properties of dopamine were studied in different experimental conditions by potentiometry, UV-spectrophotometry, and spectrofluorimetry. The distribution measurements between 2-methyl-1-propanol/pure water (or NaCl aqueous solutions up to I = 1.02 mol kg–1) were carried out at T = 298.15 K and 310.15 K. The potentiometric measurements were used to calculate the total concentration of the ligand in each phase, and from simple mass balance equations, using the free hydrogen concentration and the protonation constants, it was possible to calculate the ligand neutral species concentration and the distribution coefficient. The salting parameter and the activity coefficient of the neutral species were calculated by means of the Setschenow equation. Independently of the experimental conditions, a good agreement between the protonation constants obtained from the different techniques was obtained. The dependence of the protonation constants on ionic strength was modeled by means of the Debye–Hückel type and Specific ion Interaction Theory (SIT) approaches, and the specific interaction parameters of the ionic species were determined. For the protonation constants, the following thermodynamic values were obtained at T = 298.15 K, log K 1 H0 =10.886 ± 0.042; log K 2 H0 = 9.107 ± 0.032; at T = 310.15 K, log K 1 H0 =10.260 ± 0.024; log K 2 H0 = 8.418 ± 0.018. From the distribution measurements the following distribution coefficients at infinite dilution were obtained at T = 298.15 K, log K D 0 0 = 0.705 ± 0.013; at T = 310.15 K, log K D 0 0 = 0.983 ± 0.014.

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Thermodynamic Complexation of Dopamine with Molybdenum(VI) in Media with Different Dielectric Constants

Cited by 5 publications

References 25 publications

The Solution Behavior of Dopamine in the Presence of Mono and Divalent Cations: A Thermodynamic Investigation in Different Experimental Conditions

The Solution Behavior of Dopamine in the Presence of Mono and Divalent Cations: A Thermodynamic Investigation in Different Experimental Conditions

The Effect of Metal Cations on the Aqueous Behavior of Dopamine. Thermodynamic Investigation of the Binary and Ternary Interactions with Cd2+, Cu2+ and UO22+ in NaCl at Different Ionic Strengths and Temperatures

Thermodynamic Properties of Dopamine in Aqueous Solution. Acid–Base Properties, Distribution, and Activity Coefficients in NaCl Aqueous Solutions at Different Ionic Strengths and Temperatures

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