An Asymmetric Iron‐Based Redox‐Active System for Electrochemical Separation of Ions in Aqueous Media

Iron-based magnetic molecular imprinted polymers (Fe@SiO 2 @MIP) were synthesized for highly selective removal and recognition of di- n -pentyl phthalate (DnPP) from water. Well-defined core-shell Fe@SiO 2 nanoparticles (less than 70 nm) were decorated on MIPs reticular layers to endow DnPP-MIPs with magnetic property for the first time. Five other phthalic acid esters including dimethyl phthalate, diethyl phthalate, dipropyl phthalate, di- n -butyl phthalate and di-iso-octyl phthalate were used to investigate the adsorptive selectivity to DnPP. The designed experiments were carried out to explore the adsorption kinetics, isotherms and thermodynamics and the results demonstrated that the adsorption was a spontaneous, exothermal and physical adsorption process. The materials were proved to be excellent adsorbents in removal of DnPP with an adsorption capacity as high as 194.15 mg g −1 in optimal condition. Furthermore, a magnetic solid phase extraction with Fe@SiO 2 @MIP coupled to high-performance liquid chromatography method was successfully developed for the determination of DnPP, and the proposed method achieved a good linear range of 0.5–250 µg l −1 with a correlation coefficient ( R 2 ) of 0.999 and low limit of detection (LOD) of 0.31 µg l −1 . These materials exhibited excellent capacity in removal and highly sensitive identification of DnPP from aqueous environment samples, and opened a valuable direction for developing new adsorbents for the removal and enrichment of important pollutants.

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Water Soluble Iron-Based Coordination Trimers as Synergistic Adjuvants for Pancreatic Cancer

Antioxidants ◽

10.3390/antiox10010066 ◽

2021 ◽

Vol 10 (1) ◽

pp. 66

Author(s):

Marco Cordani ◽

Esther Resines-Urien ◽

Arturo Gamonal ◽

Paula Milán-Rois ◽

Lionel Salmon ◽

...

Keyword(s):

Pancreatic Cancer ◽

Cell Lines ◽

Pancreatic Cancer Cell ◽

Aqueous Media ◽

Coordination Complexes ◽

Water Soluble ◽

Therapeutic Approaches ◽

Iron Based ◽

High Concentrations ◽

First Time

Pancreatic cancer is a usually fatal disease that needs innovative therapeutic approaches since the current treatments are poorly effective. In this study, based on cell lines, triazole-based coordination trimers made with soluble Fe(II) in an aqueous media were explored for the first time as adjuvant agents for the treatment of this condition. These coordination complexes were effective at relatively high concentrations and led to an increase in reactive oxygen species (ROS) in two pancreatic cancer cell lines, PANC-1 and BXPC-3, and this effect was accompanied by a significant reduction in cell viability in the presence of gemcitabine (GEM). Importantly, the tested compounds enhanced the effect of GEM, an approved drug for pancreatic cancer, through apoptosis induction and downregulation of the mTOR pathway. Although further evaluation in animal-based models of pancreatic cancer is needed, these results open novel avenues for exploring these iron-based materials in biomedicine in general and in pancreatic cancer treatment.

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An iron-iron hydrogenase mimic with appended electron reservoir for efficient proton reduction in aqueous media

Science Advances ◽

10.1126/sciadv.1501014 ◽

2016 ◽

Vol 2 (1) ◽

pp. e1501014 ◽

Cited By ~ 35

Author(s):

René Becker ◽

Saeed Amirjalayer ◽

Ping Li ◽

Sander Woutersen ◽

Joost N. H. Reek

Keyword(s):

Aqueous Media ◽

Proton Reduction ◽

Time Resolved ◽

Redox Active ◽

Iron Hydrogenase ◽

Natural Enzyme ◽

Improved Stability ◽

Iron Iron ◽

Low Efficiency ◽

Time Resolved Infrared Spectroscopy

The transition from a fossil-based economy to a hydrogen-based economy requires cheap and abundant, yet stable and efficient, hydrogen production catalysts. Nature shows the potential of iron-based catalysts such as the iron-iron hydrogenase (H2ase) enzyme, which catalyzes hydrogen evolution at rates similar to platinum with low overpotential. However, existing synthetic H2ase mimics generally suffer from low efficiency and oxygen sensitivity and generally operate in organic solvents. We report on a synthetic H2ase mimic that contains a redox-active phosphole ligand as an electron reservoir, a feature that is also crucial for the working of the natural enzyme. Using a combination of (spectro)electrochemistry and time-resolved infrared spectroscopy, we elucidate the unique redox behavior of the catalyst. We find that the electron reservoir actively partakes in the reduction of protons and that its electron-rich redox states are stabilized through ligand protonation. In dilute sulfuric acid, the catalyst has a turnover frequency of 7.0 × 104s−1at an overpotential of 0.66 V. This catalyst is tolerant to the presence of oxygen, thereby paving the way for a new generation of synthetic H2ase mimics that combine the benefits of the enzyme with synthetic versatility and improved stability.

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A Redox Conjugated Polymer-Based All-Solid-State Reference Electrode

Polymers ◽

10.3390/polym10111191 ◽

2018 ◽

Vol 10 (11) ◽

pp. 1191 ◽

Cited By ~ 7

Author(s):

Ke Qu ◽

Mingxi Fang ◽

Shuwei Zhang ◽

Haiying Liu ◽

Xiangqun Zeng

Keyword(s):

Solid State ◽

Aqueous Media ◽

Reference Electrode ◽

Design Synthesis ◽

Zero Current ◽

Redox Active ◽

Reversible Redox ◽

Strong Lewis Acid ◽

State Reference ◽

Poly Aniline

This work reports the design, synthesis, and characterization of a novel redox-active conjugated polyaniline containing quinone moiety as a solid state reference electrode. The union of electro-active quinone with π-conjugated polyaniline was created by the first chemical synthesis of para-dimethoxybenzene-functionalized aniline as a monomer using a palladium-mediated coupling. The successful polymerization of the as-prepared monomer was accomplished without acid additives. Its post-polymerization modification with strong Lewis acid boron tribromide furnished unique poly (aniline quinone/hydroquinone) with desired properties for all-solid-state reference electrode (RE) applications. The electrochemical responses from the conjugated polyaniline backbone in this unique polymer have been “suppressed” by the quinone pendant. The resulting poly (aniline quinone) showed a quasi-reversible redox process from the redox behavior of the pendant quinone. The stable electrode potential of this poly (aniline quinone/hydroquinone) suggested that it was a single phase in which the amounts of totally reduced and totally oxidized species could be maintained at a constant in various solvents and electrolytes. Its electrochemical stability was excellent with 95% peak current retention after continuous cyclic voltammetric testing. The aniline and quinone moieties in poly (aniline quinone/hydroquinone) render it to have both hydrophilic and hydrophobic compatibility. It showed excellent behavior as a reference electrode in aqueous and non-aqueous media and can be used in both non-zero current and zero-current conditions, providing a stable potential with a maximum potential drift of ~4.7 mV over ten consecutive days.

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Self-Assembled Monolayer of a Redox-Active Calix[4]arene: Voltammetric Recognition of the Ba2+Ion in Aqueous Media

Analytical Chemistry ◽

10.1021/ac001050p ◽

2001 ◽

Vol 73 (16) ◽

pp. 3975-3980 ◽

Cited By ~ 34

Author(s):

Taek Dong Chung ◽

Jongseo Park ◽

Jandee Kim ◽

Hyunchang Lim ◽

Mi-Jung Choi ◽

...

Keyword(s):

Aqueous Media ◽

Self Assembled Monolayer ◽

Redox Active ◽

Self Assembled

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Modeling the OEC with Two New Biomimetic Models: Preparations, Structural Characterization, and Water Photolysis Studies of a Ba–Mn Box Type Complex and a Mn4N6 Planar-Diamond Cluster

Catalysts ◽

10.3390/catal8090382 ◽

2018 ◽

Vol 8 (9) ◽

pp. 382 ◽

Cited By ~ 1

Author(s):

Lara Rouco ◽

M. Fernández-García ◽

Rosa Pedrido ◽

Luis Botana ◽

David Esteban-Gómez ◽

...

Keyword(s):

Uv Spectroscopy ◽

Aqueous Media ◽

Oxygen Evolving Complex ◽

X Ray Diffraction ◽

Water Photolysis ◽

Biomimetic Models ◽

Redox Active ◽

Oxygen Evolving ◽

Natural Photosynthesis ◽

Diamond Cluster

The oxygen-evolving complex (OEC) is the native enzyme that catalyzes the oxidation of water in natural photosynthesis. Two new classes of manganese cluster complexes of formula Ba2Mn2L12(H3L1)2(CH3OH)4 1 and Mn4L26Cl2 2 were prepared (H4L1 = N,N′-(ethane-1,2-diyl)bis(2-hydroxybenzamide); L2 = methyl picolinimidate) and characterized by standard techniques including microanalysis, IR spectroscopy, ESI spectrometry, and magnetic susceptibility measurements. X-ray diffraction studies of these complexes revealed (i) a box-type structure for 1 formed by two redox-active manganese(III) ions and two barium(II) ions connected by two bridging bisamido-bisphenoxy ligand molecules; and (ii) a planar-diamond array for Mn4N6 cluster 2 where the picolinimidates act as chelating ligands through the two nitrogen atoms. The ability of 1 and 2 to split water has been studied by means of water photolysis experiments. In these experiments, the oxygen evolution was measured in aqueous media in the presence of p-benzoquinone (acting as the hydrogen acceptor), the reduction of which was followed by UV-spectroscopy. The relevant photolytic activity found for 1 is in contrast to the inactivity of 2 in the photolytic experiments. This different behavior is discussed on the basis of the structure of the biomimetic models and the proposed reaction mechanism for this process supported by DFT calculations.

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