Abstract
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+.
Highlights
Dopamine (Scheme 1) is a therapeutic form of a substance that naturally occurs in the body
The difficulties in comparing the results reported in the different papers are 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]
The speciation studies carried out on dopamine interactions towards binary e ternary UO22+, Cu2+ and Cd2+/dopamine systems lead to the following conclusions: 1. quite different speciation models were obtained for the three different binary systems
Summary
Dopamine (Scheme 1) is a therapeutic form of a substance that naturally occurs in the body. It works by improving the pump force of the heart and improves blood flow to the kidneys. Dopamine is used to treat certain conditions that occur when there is a shock, which can be caused by heart attack, trauma, surgery, heart failure, kidney failure, and other serious medical conditions [1,2,3,4]. Molecules 2021, 26, 7679 Molecules 2021, 26, 7679 which can be caused by heart attack, trauma, surgery, heart failure, kidney failure, and other serious medical conditions [1,2,3,4]. Dopamine is an important neurotransmitter of the ccaatteecchhoollaammiinnee ffaammiilyly, ,wwithitha caonctoronltfruonl cftuionnctoionnmoovnemmeonvte, mtheensto, -cthaleledsow-coarlkleidngwmoermkionrgy, mtheemsoenrysa, ttihoensoefnpsaletaiosnuroef, tphleeapsruordeu, cthtieonproofdpurcotliaocntino,f splereoplarcetignu,lsalteioepn mreegcuhlaatniiosnmms,escohma-e nciosgmnsi,tisvoemfeuncoctginointisv, eanfudntchtieonasb,ilaintydothf eatatbeinlittiyono.f aItttaelnstoioanll.oIwt aslstohealcloewllss othf ethceelnlseorvf othues nseyrsvteomustsoycsotemmmtuonciocmatemwunitihcaetaecwh iotthheear.ch other.
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
