Oxygen evolution reaction (OER) is the key step involved both in water splitting devices and rechargeable metal-air batteries, and hence, there is an urgent need for a stable and low-cost material ...for efficient OER. In the present investigation, Co−Fe−Ga−Ni−Zn (CFGNZ) high entropy alloy (HEA) has been utilized as a low-cost electrocatalyst for OER. Herein, after cyclic voltammetry activation, CFGNZ-nanoparticles (NPs) are covered with oxidized surface and form high entropy (oxy) hydroxides (HEOs), exhibiting a low overpotential of 370 mV to achieve a current density of 10 mA/cm
2
with a small Tafel slope of 71 mV/dec. CFGNZ alloy has higher electrochemical stability in comparison to state-of-the art RuO
2
electrocatalyst as no degradation has been observed up to 10 h of chronoamperometry. Transmission electron microscopy (TEM) studies after 10 h of long-term chronoamperometry test showed no change in the crystal structure, which confirmed the high stability of CFGNZ. The density functional theory (DFT) based calculations show that the closeness of d(p)-band centers to the Fermi level (
E
F
) plays a major role in determining active sites. This work highlights the tremendous potential of CFGNZ HEA for OER, which is the primary reaction involved in water splitting.
•Synthesis of five diorganotin(IV) complexes.•Structural characterization by FT-IR, 1H, 13C NMR spectroscopy and mass spectrometery.•Single crystal X-ray analysis confirms the solid state molecular ...structure of complexes with seven coordinated tin center and pentagonal bipyramidal geometry.•DNA interaction study through UV-Vis spectroscopy, viscometery and cyclic voltametery•Antioxidant activity and cytotoxicity against human breast cancer cell line MDA-MB-231
Five new organotin(IV) complexes, Me2SnL (1), n-Bu2SnL (2), tert-Bu2SnL (3), Ph2SnL (4) and n-Oct2SnL (5), have been synthesized from the reaction of R2SnCl2 (R= Me, Bu, tert-Bu, Ph, Oct) with N'-(3-ethoxy-2-hydroxybenzylidene)formohydrazide (H2L). The structural elucidation of synthesized compounds was done by FT-IR, 1H-NMR, 13C-NMR spectroscopy and single-crystal X-ray analysis. Crystallographic data of complex (1) showed seven coordinated central tin atom with distorted pentagonal bipyramidal geometry. Where in solution the Sn atom of synthesized complexes exhibit five coordination, confirmed from 1H-NMR. The results from DNA interaction studies via UV-visible spectroscopy, viscosity, cyclic voltammetry, and differential pulse voltammetry (DPV) suggested an intercalative mode of interaction between the synthesized compounds and SS-DNA. Furthermore, the complexes interact more significantly than ligand. Electrochemical and thermodynamic parameters, including diffusion coefficient, ∆H, ∆G, and ∆S, were calculated using cyclic voltammetry data. The linear plot of peak current (I) vs. square root of the scan rate (υ1/2) indicated the electrochemical processes to be diffusion controlled. The DPPH free radical scavenging assay results showed that complex (4) is an active antioxidant. In-vitro cytotoxicity of the synthesized compounds was determined on human breast cancer cell line MDA-MB-231 using tetrazolium-based MTT assay, and complexes (2), (3) and (4) showed significant cytotoxic activity. The structure-activity relationships may be utilised to direct the optimization of the activity of agents from this class of compounds by comparing the specifics of the compound structures, their DNA binding, and toxicity.
DNA binding interaction of the new diorganotin(IV) complexes was studied by UV-Visible spectrophotometry, viscometry and electrochemical techniques. The antioxidant activity and cytotoxicity against human breast cancer cell line MDA-MB-231 was also determined. Display omitted
Nickel (Ni) current collectors having a three-dimensional and porous structure are considered attractive contestants for high-efficiency supercapacitors. Therefore, Ni current collectors have a ...unique architecture and outstanding electrochemical properties. This study reports the effect of electrochemical characterizations on the electrochemical behavior and physical properties of Ni mesh and Ni foam. Cyclic voltammetry (CV) and galvanostatic charge discharge (GCD) are used to examine the electrochemical properties and life span of the Ni mesh and Ni foam as a current collector in a supercapacitor application. Structural and microstructural characterizations are performed to verify the formation of an oxide layer after 1000 cycles of CV analysis. Results show that Ni foam can increase the yield electrochemical performance of the supercapacitor. Ni foam present better efficiency (35 F g−1) compared to the Ni mesh (12 F g−1) at 10 mV s−1 scan rate by using 2 mg imaginary mass of active material. This result shows that Ni foam has good electrochemical performance and reversibility, higher pseudocapacitance, weaker polarization, and enhance rotating performance as to Ni mesh. The porous structure of Ni foam is in control for improving of the electrochemical properties, therefore, the electrochemical region was increased and shortened ion diffusion. Structural analysis shows that Ni mesh and Ni foam are oxidized after the electrochemical analysis and transformed to nickel oxide hydroxide (NiOOH). Higher specific surface area between the electrode and electrolyte leads to excellent electrochemical and pseudocapacitive performance of the Ni foam compared to the Ni mesh, even if the materials of current collectors are the same. Hence, the physical structure of the current collectors have a critical part in improving the energy density of the supercapacitor.
Abstract Poly (Tin-doped copper oxide nanocomposites modified glassy carbon electrode) (Poly (Sn-doped CuO nanocomposite)-MGCE) made sensors were confirmed by electrochemical finding of ...norepinephrine (NE). The Sn-doped CuO nanocomposites were made by precipitation technique. This nanocomposite was described through scanning electron microscope and X-ray diffraction methods. To find the doped properties of the Poly (Sn-doped CuO nanocomposite)-MGCE were studied by cyclic voltammetry studies. The above studies prove that the altered electrodes have wide electroactive external area, and the reduction and oxidation peak appeared at pH 7.4 supportive electrolyte concentration 0.2 M phosphate buffer solution. Poly(Sn-doped CuO nanocomposite)-MGCE as limit of detection was low value for NE was found to be 2.22 µM and the limit of quantification values for NE was appeared as 7.41 µM, wide linear range, high sensitivity (20 to 350 µM), functional to the injection mockup analysis and the attained outcomes are acceptable, excellent reproducibility displays excessive potential in practical applications.
•In the current manuscript, we have reported mononuclear nickel and dinuclear palladium complexes of composition Ni(L) (1) and Pd2(L)Cl2.CH2Cl2 (2), respectively supported by hexadentate ...ligand.•Density functional theory (DFT) calculation at the B3LYP level of theory has been utilized to assign not only the correct oxidation state of the metal ion but also the oxidation level of the coordinated ligands in each complex.•In current manuscript, we have attempted to highlights the importance of ligand design with varied denticity, donor atom type, rigidity/flexibility, bridging capability, and successful use of such ligands to synthesize several noteworthy transition metal complexes.
“A new potentially hexadentate redox-active schiff base ligand, H2L = 2-((Z)-(2-(2-(2-((Z)-3,5-di‑tert‑butyl‑2-hydroxybenzylideneamino)phenylthio)ethylthio)phenylimino)methyl)-4,6-di‑tert-butylphenol, reacts with NiII(O2CCH3)2·4H2O and PdCl2 in CH3OH in the presence of air and Et3N affording isolation of yellow and red crystalline solids of composition Ni(L) (1) and Pd2(L)Cl2.2CH2Cl2 (2), respectively. When examined by cyclic voltammetry (CV), 1 exhibits three quasireversible responses at E1/2 = 0.60 V (peak-to peak separation, ΔEp = 80 mV), 0.96 V (ΔEp = 80 mV) and 1.16 V (ΔEp = 160 mV) vs SCE (saturated calomel electrode); while 2 exhibits one quasireversible response at E1/2 = 1.185 V (peak-to peak separation, ΔEp = 130 mV). One electron oxidized species showed EPR spectrum correspond to ferromagnetically coupled system, S = 3/2 (S = 1 for NiII and S = ½ for phenoxyl radical). Structural analysis revealed that 1 is discrete mononuclear and 2 is discrete dinuclear coordination complex. In complex 1, each NiII is in distorted octahedral NiN2O2S2 environment where coordination is satisfied by two nitrogen atoms, two oxygen atoms and two sulfur atoms of the ligand. In complex 2, each Pd is in distorted square planner PdNOSCl environment where coordination is satisfied by one each nitrogen, oxygen and sulfur atoms of the ligand, and a chloride ion. DFT calculations at B3LYP-level of theory adequately describe the electronic structures of 1 and 2, containing a spin-unpaired d8 NiII ion and spin-paired d8 PdII ion. Time-dependent-DFT calculations on 1 and 2 shed light on the origin of UV−vis−NIR spectral absorptions.
We report computational and experimental correlation in mononuclear Nickel(II) and Dinuclear Palladium(II) Complexes of a Redox-Active Iminophenolate-Based Ligand
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Lipophilicity of the compounds is useful to (i) explain their distribution in biological systems, which is different in plant and in animal organisms, (ii) predict the possible pathways of pollutant ...transport in the environment, and (iii) support drug discovery process and select optimal composition in terms of bioactivity and bioavailability. The lipophilic properties can be determined by two main approaches, experimental, which apply instrumental techniques or computational, which is based on the complex algorithms. This review focuses primarily on various analytical methods that are used in the lipophilicity measurements. The classical methods and others based on chromatographic, electroanalytical and electroseparation approaches are compared and described in details. Modern solutions with chromatographic systems and their practical applications in the measurements of lipophilic and biomimetic properties of compounds have been included. However, there is an urgent need to standardize the high-throughput and reliable analytical procedure of the evaluation of lipophilic properties.
•The role of lipophilicity in biological, environmental and technical science.•Lipophilicity assessment using classical and modern approaches.•Advantages and limitations of methods of lipophilicity determination.•Novel solutions in chromatographic methods used for lipophilicity determination.
We report the synthesis of alloyed quaternary and quinary nanocrystals based on copper chalcogenides, namely, copper zinc selenide–sulfide (CZSeS), copper tin selenide–sulfide (CTSeS), and copper ...zinc tin selenide–sulfide (CZTSeS) nanoplatelets (NPLs) (∼20 nm wide) with tunable chemical composition. Our synthesis scheme consisted of two facile steps: i.e., the preparation of copper selenide–sulfide (Cu2–x Se y S1–y ) platelet shaped nanocrystals via the colloidal route, followed by an in situ cation exchange reaction. During the latter step, the cation exchange proceeded through a partial replacement of copper ions by zinc or/and tin cations, yielding homogeneously alloyed nanocrystals with platelet shape. Overall, the chemical composition of the alloyed nanocrystals can easily be controlled by the amount of precursors that contain cations of interest (e.g., Zn, Sn) to be incorporated/alloyed. We have also optimized the reaction conditions that allow a complete preservation of the size, morphology, and crystal structure as that of the starting Cu2–x Se y S1–y NPLs. The alloyed NPLs were characterized by optical spectroscopy (UV–vis–NIR) and cyclic voltammetry (CV), which demonstrated tunability of their light absorption characteristics as well as their electrochemical band gaps.
Numerous neurochemicals have been implicated in the modulation of brain function, making them appealing analytes for sensors and diagnostics. However, it is a grand challenge to selectively measure ...multiple neurochemicals simultaneously in vivo because of their great variations in concentrations, dynamic nature, and composition. Herein, we present a deep learning‐based voltammetric sensing platform for the highly selective and simultaneous analysis of three neurochemicals in a living animal brain. The system features a carbon fiber electrode capable of capturing the mixed dynamics of a neurotransmitter, neuromodulator, and ions. Then a powerful deep neural network is employed to resolve individual chemical and spatial‐temporal information. With this, a single electrochemical measurement reveals an interplaying concentration changes of dopamine, ascorbate, and ions in living rat brain, which is unobtainable with existing analytical methodologies. Our strategy provides a powerful means to expedite research in neuroscience and empower sensing‐aided diagnostic applications.
A deep learning‐based voltammetric (DLV) sensing platform is developed for highly selective and multiplexed analysis of neurochemicals in vivo. With the DLV sensor, we reveal the interplay between the concentrations of dopamine, ascorbate, and ions in the living rat brain, which is unobtainable with existing methods. Our strategy provides a powerful means to expedite basic research in neuroscience and empower sensing‐aided diagnostic applications.
•New bisphosphonate acid was synthesized and identified.•Antioxidant activities as DPPH scavenging and ferric reducing power is performed to elucidate the inhibitory capacity of the investigated ...compound.•Scavenging superoxide activity via cyclic voltammetry: assessment of IC50 and thermodynamic factors (Gibbs free energy, stability constant Kb).•Molecular docking of the ligand with SARS-CoV-2 main protease, determination of the binding energy attributed to the best conformation ΔG° and of interactions of hydrogen and Hydrophobicbonds, while comparing to chloroquine drug.
In this study, we have synthesized a new molecule labeled HBPA. Its molecular structure was determined by spectroscopic methods such as: FT-IR, NMR (1H, 13C and 31P); our compound is subjected to two antioxidant activities assays: DPPH scavenging and ferric reducing antioxidant power (FRAP); in the results, HBPA was expanded remarkable inhibition when compared especially to standard BHT with values of 14.936±0.808 and 7.1486±0.0645 μg/ml, respectively; in addition to the scavenging test of superoxide anion integrated in electrochemical process, it elucidated a strongly stable interaction towards the radical by evaluating the thermodynamic descriptors (Gibbs free energy ΔG° and the binding constant Kb). Besides, the electrochemical behavior of HBPA was distinguished by an irreversible system and for the electrochemical regime adopted at the surface of the electrode; a diffusion governed by a slow charge transfer was deduced. The molecular docking of HBPA was conducted beside Chloroquine and the obtained results were indicated a significant binding with active sites of the SARS-CoV-2 main protease (Mpro).
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