A study of the aerobic reaction between dopamine and Fe(III) in the presence of S2O3 2−

Abstract

The reaction between Fe(III) and dopamine in aqueous solution in the presence of Na 2 S 2 O 3 was followed through UV-Vis spectroscopy, pH and oxyreduction potential (Eh) measurements. The formation and quick disappearing of the complex [Fe(III)HL 1-] 2? , HL 1-= monoprotonated dopamine was observed with or without S 2 O 3 2-at pH 3. An unexpected reaction occurs in presence of thiosulfate forming the stable anion complex [Fe(III)(L 2-) 2 ] 1-, L 2-= dopacatecholate (k = 580 nm) and the auto-increasing of the pH, from 3 to 7. It was proposed that H ? and molecular oxygen are consumed by free radical thiosulfate formed during the reaction.

Bright light exposure reduces TH-positive dopamine neurons: implications of light pollution in Parkinson's disease epidemiology

“…It is interesting to note that dopamine in complex with Fe 3+ shows two bands of absorbance7, with maxima at 437 and 740 nm. Zecca20 and coworkers have shown that conversion of dopamine to neuromelanin is prompted by iron because the chelator desferrioxamine is able to block neuromelanin synthesis.…”

“…The rationale to investigate the effect of light on neuromelanin formation in the substantia nigra arises from evidence that dopamine in complex with iron can absorb in the visible light spectrum. Barreto et al 7. have shown that in the presence of Fe(NO 3 ) 3 two broad bands of dopamine absorbance appear, with maxima at 437 and 740 nm.…”

The interplay of catechol ligands with nanoparticulate iron oxides

“…The interaction between Fe(II) and Fe(III) with catechols, especially dopamine derivatives, is of particular interest in a biological setting as ironpromoted oxidative polymerisation of dopamine gives rise to the melanin pigments and the intermediate iron-semiquinone radical species are implicated in the pathology of Parkinson's disease. 34,35 This perspective discusses certain aspects of the interaction between iron oxide nanoparticles and catechol derivatives, with the focus being on dopamine-like ligands. It begins with a brief overview of the nature of the iron-catecholate bond, followed by the effect catecholates can have on the desirable magnetic properties of SPIONs as a result of the strong metal-ligand interactions.…”

An Unprecedented FeMo6@Ce‐Uio‐66 Nanocomposite with Cascade Enzyme‐Mimic Activity as Colorimetric Sensing Platform

“…[38] At the same time, DA also continuously reduces Fe 3 + into Fe 2 + through electron transfer, which in turn produces •OH through the Fenton-like reaction of activated H 2 O 2 . [39] Thus, the successive generation of •OH dramatically improves the conversion efficiency of non-fluorescent OPD to fluorescent DAP, leading to a remarkable fluorescence enhancement phenomenon.…”

“…Thus the cerium cycle, the slightly distorted [Ce 6 O 4 (OH) 4 ] 12+ cluster containing Ce(IV) reconstitutes Ce(III) with the help of O 2 ⋅− , was completed; [36,37] (2) the H 2 O 2 species produced in step 1 with localized high concentrations around the [Ce 6 O 4 (OH) 4 ] 12+ cluster are immediately catalyzed by FeMo 6 to decompose into hydroxyl radicals(⋅OH) and further oxidizing OPD; [29] (3) when DA is introduced, the auto‐oxidation of DA in the presence of O 2 leads to the continuous production of ⋅OH, which is further facilitated by the Fe 3+ on Fe‐ μ ‐oxo in FC‐66 [38] . At the same time, DA also continuously reduces Fe 3+ into Fe 2+ through electron transfer, which in turn produces ⋅OH through the Fenton‐like reaction of activated H 2 O 2 [39] . Thus, the successive generation of ⋅OH dramatically improves the conversion efficiency of non‐fluorescent OPD to fluorescent DAP, leading to a remarkable fluorescence enhancement phenomenon.…”