Interfacing Formate Dehydrogenase with Metal Oxides for the Reversible Electrocatalysis and Solar‐Driven Reduction of Carbon Dioxide

The integration of enzymes with synthetic materials allows efficient electrocatalysis and production of solar fuels. Here, we couple formate dehydrogenase ( FDH ) from Desulfovibrio vulgaris Hildenborough (DvH) to metal oxides for catalytic CO₂ reduction and report an in‐depth study of the resulting enzyme–material interface. Protein film voltammetry (PFV) demonstrates the stable binding of FDH on metal‐oxide electrodes and reveals the reversible and selective reduction of CO₂ to formate. Quartz crystal microbalance (QCM) and attenuated total reflection infrared (ATR‐IR) spectroscopy confirm a high binding affinity for FDH to the TiO₂ surface. Adsorption of FDH on dye‐sensitized TiO₂ allows for visible‐light‐driven CO₂ reduction to formate in the absence of a soluble redox mediator with a turnover frequency (TOF) of 11±1 s^?1. The strong coupling of the enzyme to the semiconductor gives rise to a new benchmark in the selective photoreduction of aqueous CO₂ to formate.     

Obtaining and characterizing modified tannins by physical-chemical methods

After oxidation of tannins (Tannins 1–3) extracted from grape seeds, Tanoxil compounds with increased solubility and enhanced antioxidant activities were synthesized. In this research, ABTS^+· assay and a chemiluminescence method were used for antioxidant measurement of hydrophilic compounds (Tanoxils 1–3).

It was observed that the antioxidant activity (AA, %) is very similar for the three samples, while at the same time AA is quite high (93.16%–96.48%). The percentage of inhibition by ABTS^+· is higher for Tanoxil 2 (96.4%) as compared to Tannin 2 compound (14.34%). Moreover, the total content (T_CF) of carboxyl and phenolic groups was investigated. T_CF values, determined for Tanoxil products, revealed a double (Tanoxil 1) or triple (Tanoxil 2) increase as compared to the value of the T_CF of Tannin 1. Tanoxil products represent an interest for future research as they have a high AA (96.4%) and the content of acidic groups is significant (T_CF, 0.191 meq g^?1).

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2-Halopyridines in the triple reaction in the Pn/KOH/DMSO system to form tri(2-pyridyl)phosphine: Experimental and quantum-chemical dissimilarities

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The conformation of epinephrine in polar solvents: an NMR study

Structural Chemistry - Epinephrine (Epi) is a physiologically important catecholamine. Molecular conformation of Epi controls the interactions with other molecules and its biological effects. There...     

This electrode is best served cold—a reversible electrochemical lithiation of a gray cubic tin

Journal of Solid State Electrochemistry - The behavior of a cubic allotropic modification of tin (α-Sn) towards lithium electrochemical alloying/de-alloying is reported for the first time. The...     

Anodic corrosion of gold in solutions of diaminoalkanes

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Synthesis of hybrid structures comprising diaziridine and cyclopropane rings in one molecule

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Study of electrooxidation of binary electrolytic deposit palladium–bismuth deposited on graphite electrode surface

The phase structure of palladium–bismuth binary electrolytic deposit was studied. The electrodeposition of deposit components on the surface of a graphite electrode (GE) was carried out in situ. On current–voltage curves, the peak of bismuth electrooxidation, the peak of palladium electrooxidation and an additional peak at 0.15 V vs. Ag/AgCl are observed. The peak current at 0.15 V depends both on the concentration of palladium(II) ions and on that of bismuth(III) ions. The thermodynamic theory of alloys in the approximation of the theory of regular solutions was used for calculations. The mixing heat of the binary alloy components and the equilibrium potential of bismuth in the bismuth–palladium alloy are calculated. The calculated equilibrium potential of bismuth in an alloy with palladium is 0.12 V vs. Ag/AgCl which corresponds to the Bi₂Pd intermetallic compound (IMC). Investigation of the surface of a GE with a palladium–bismuth deposit with use of scanning electron microscope showed that the electrolytic deposit contains bismuth, palladium and the Bi₂Pd IMC. Peak at the potential of plus 0.15 V vs. Ag/AgCl is due to selective bismuth electrooxidation from the Bi₂Pd IMC.     

Catalyzed Asymmetric Arylation Reactions

Addition and substitution reactions with carbon nucleophiles are fundamental processes in organic synthesis, and the development of general catalytic asymmetric variants thereof is still a major challenge today. In contrast to enantioselective alkyl transfer reactions, the corresponding arylations have not yet reached a high level of maturity. The existing protocols are either of no general applicability or are limited in terms of selectivity. This article summarizes established routes for catalytic asymmetric aryl transfer together with the latest developments in this area. The scope and limitations of this reaction are discussed.     

Spectroscopic study and antioxidant activity of the inclusion complexes of cyclodextrins and amlodipine besylate drug

The aim of the study was to synthesize and characterization the inclusion complexes of amlodipine besylate (AML) drug with β-cyclodextrin (β-CD) and γ-cyclodextrin (γ-CD) which has antioxidating activity property. The guest/host interaction of AML with β-CD and γ-CD in order to complexation drug in β-CD and γ-CD were investigated. The interaction inclusion complexes was characterized by fourier transform infrared and ultraviolet–visible spectroscopies. The formation constant was calculated by using a modified Benesi–Hildebrand equation at 25 °C. The stoichiometry of inclusion complexes was found to be 1:1 for β-CD and γ-CD with AML drug. The antioxidant activity of AML drug and its inclusion complexes were determined by the scavenging of stable radical 2,2′-diphenyl-1-picrylhydrazyl (DPPH^·). Kinetic studies of DPPH^· with AML and CDs complexes were done. The experimental results confirmed the forming of AML complexes with CDs also these indicated that the AML/β-CD and AML/γ-CD inclusion complexes was the most reactive than its free form into antioxidant activity.