Diaqua-β-octaferrocenyltetraphenylporphyrin: a multiredox-active and air-stable 16π non-aromatic species

2019 ◽  
Vol 48 (5) ◽  
pp. 1578-1585 ◽  
Author(s):  
Rasha K. Al-Shewiki ◽  
Marcus Korb ◽  
Alexander Hildebrandt ◽  
Stefan Zahn ◽  
Sergej Naumov ◽  
...  
Keyword(s):  
Reversible Redox ◽  
Aromatic Species

Herein the synthesis and properties of the first β-octaferrocenyltetraphenylporphyrin, {TPPFc8(H2O)2}, in its extraordinary stable and non-aromatic 16π form are reported, showing seven separate reversible redox events.

Strongly Coupled Redox-Linked Conformational Switching at the Active Site of the Non-Heme Iron-Dependent Dioxygenase, TauD

2019 ◽  
Author(s):  
Christopher John ◽  
Greg M. Swain ◽  
Robert P. Hausinger ◽  
Denis A. Proshlyakov
Keyword(s):  
Active Site ◽  
Structural Model ◽  
Heme Iron ◽  
Chemical Transformations ◽  
Experimental Conditions ◽  
Strongly Coupled ◽  
Non Heme Iron ◽  
Reversible Redox ◽  
Wide Range ◽  
Complex Structural

2-Oxoglutarate (2OG)-dependent dioxygenases catalyze C-H activation while performing a wide range of chemical transformations. In contrast to their heme analogues, non-heme iron centers afford greater structural flexibility with important implications for their diverse catalytic mechanisms. We characterize an <i>in situ</i> structural model of the putative transient ferric intermediate of 2OG:taurine dioxygenase (TauD) by using a combination of spectroelectrochemical and semi-empirical computational methods, demonstrating that the Fe (III/II) transition involves a substantial, fully reversible, redox-linked conformational change at the active site. This rearrangement alters the apparent redox potential of the active site between -127 mV for reduction of the ferric state and 171 mV for oxidation of the ferrous state of the 2OG-Fe-TauD complex. Structural perturbations exhibit limited sensitivity to mediator concentrations and potential pulse duration. Similar changes were observed in the Fe-TauD and taurine-2OG-Fe-TauD complexes, thus attributing the reorganization to the protein moiety rather than the cosubstrates. Redox difference infrared spectra indicate a reorganization of the protein backbone in addition to the involvement of carboxylate and histidine ligands. Quantitative modeling of the transient redox response using two alternative reaction schemes across a variety of experimental conditions strongly supports the proposal for intrinsic protein reorganization as the origin of the experimental observations.

Discovery of THICZs as Chemical Sensors: Synthesis, Spectrophotometric,Voltammetric and DFT Studies

2019 ◽  
Vol 09 ◽  
Author(s):  
Mardia T. El Sayed ◽  
Ibrahim H.I. Habib ◽  
Nermien M. Sabry ◽  
Sergey A. Pisarev ◽  
Mohamed El-Naggar ◽  
...  
Keyword(s):  
Electrochemical Behaviour ◽  
Molecular Size ◽  
Active Species ◽  
Carbon Paste ◽  
Reversible Redox ◽  
Energy Relationships ◽  
Linear Solvation Energy ◽  
Solute Interactions ◽  
Homo Lumo ◽  
Paste Electrode

Absorption spectra of tetrahydro[3,2-b]indolo-carbazoles (THICZs) with various molecular size and alkyl tails have been recorded in various solvents in the range between 200 to 600 nm. The photo physical behaviour of dissolved THICZs depends on the nature of its environment. The solvatochromic behaviours of THICZs and solvent solute interactions can be analysed by means of linear solvation energy relationships concept proposed by Kamlet and Taft. Compound 4 show excellent properties for sensing small molecules. The electrochemical behaviour of some THICZs was investigated at carbon paste electrode where two electrode reactions were involved, irreversible oxidation-one electron transfer and quasi-reversible redox reactions forming phenolic followed by quinolone moiety electro active species. The DFT-calculated molecular orbital energies (B3LYP/6-31G) and HOMO-LUMO gaps for some presented indolocarbazoles have been performed.

scholarly journals Enhanced Production of the Mical Redox Domain for Enzymology and F-actin Disassembly Assays

2021 ◽  
Vol 22 (4) ◽  
pp. 1991
Author(s):  
Jimok Yoon ◽  
Heng Wu ◽  
Ruei-Jiun Hung ◽  
Jonathan R. Terman
Keyword(s):  
Nicotinamide Adenine Dinucleotide Phosphate ◽  
Actin Dynamics ◽  
Specific Substrate ◽  
Actin Assembly ◽  
Redox Enzymes ◽  
Enhanced Production ◽  
Reversible Redox ◽  
Future Work ◽  
Signaling Process

To change their behaviors, cells require actin proteins to assemble together into long polymers/filaments—and so a critical goal is to understand the factors that control this actin filament (F-actin) assembly and stability. We have identified a family of unusual actin regulators, the MICALs, which are flavoprotein monooxygenase/hydroxylase enzymes that associate with flavin adenine dinucleotide (FAD) and use the co-enzyme nicotinamide adenine dinucleotide phosphate (NADPH) in Redox reactions. F-actin is a specific substrate for these MICAL Redox enzymes, which oxidize specific amino acids within actin to destabilize actin filaments. Furthermore, this MICAL-catalyzed reaction is reversed by another family of Redox enzymes (SelR/MsrB enzymes)—thereby revealing a reversible Redox signaling process and biochemical mechanism regulating actin dynamics. Interestingly, in addition to the MICALs’ Redox enzymatic portion through which MICALs covalently modify and affect actin, MICALs have multiple other domains. Less is known about the roles of these other MICAL domains. Here we provide approaches for obtaining high levels of recombinant protein for the Redox only portion of Mical and demonstrate its catalytic and F-actin disassembly activity. These results provide a ground state for future work aimed at defining the role of the other domains of Mical — including characterizing their effects on Mical’s Redox enzymatic and F-actin disassembly activity.

A copper-impregnated BEA zeolite for adsorption and oxidation of aromatic species during vehicle cold starts

2021 ◽  
Vol 287 ◽  
pp. 119951
Author(s):  
Eunhee Jang ◽  
Layoung Choi ◽  
Jinseong Kim ◽  
Yanghwan Jeong ◽  
Hionsuck Baik ◽  
...  
Keyword(s):  
Bea Zeolite ◽  
Aromatic Species ◽  
Cold Starts

scholarly journals Metabolomics and DNA-Based Authentication of Two Traditional Asian Medicinal and Aromatic Species of Salvia subg. Perovskia

Cells ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 112
Author(s):  
Monika Bielecka ◽  
Bartosz Pencakowski ◽  
Marta Stafiniak ◽  
Klemens Jakubowski ◽  
Mehdi Rahimmalek ◽  
...  
Keyword(s):  
Dna Barcoding ◽  
High Performance ◽  
Carnosic Acid ◽  
Limited Information ◽  
Metabolomic Analysis ◽  
Separate Species ◽  
Flight Mass Spectrometry ◽  
Aerial Parts ◽  
Central Asian ◽  
Aromatic Species

Subgenus Perovskia of the extended genus of Salvia comprises several Central Asian medicinal and aromatic species, of which S. yangii and S. abrotanoides are the most widespread. These plants are cultivated in Europe as robust ornamentals, and several cultivars are available. However, their medicinal potential remains underutilized because of limited information about their phytochemical and genetic diversity. Thus, we combined an ultra-high performance liquid chromatography quadrupole time of flight mass spectrometry (UHPLC-QTOF-MS) based metabolomics with DNA barcoding approach based on trnH-psbA and ITS2 barcodes to clarify the relationships between these two taxa. Metabolomic analysis demonstrated that aerial parts are more similar than roots and none of the major compounds stand out as distinct. Sugiol in S. yangii leaves and carnosic acid quinone in S. abrotanoides were mostly responsible for their chemical differentiation, whereas in roots the distinction was supported by the presence of five norditerpenoids in S. yangii and two flavonoids and one norditerpenoid in S. abrotanoides. To verify the metabolomics-based differentiation, we performed DNA authentication that revealed S. yangii and S. abrotanoides to be very closely related but separate species. We demonstrated that DNA barcoding coupled with parallel LC-MS profiling constitutes a powerful tool in identification of taxonomically close Salvia species.

scholarly journals A four-electron Zn-I2 aqueous battery enabled by reversible I−/I2/I+ conversion

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Yiping Zou ◽  
Tingting Liu ◽  
Qijun Du ◽  
Yingying Li ◽  
Haibo Yi ◽  
...  
Keyword(s):  
Aqueous Electrolyte ◽  
Chloride Ions ◽  
Experimental Characterization ◽  
Redox Couples ◽  
Free Chloride ◽  
Reversible Redox ◽  
Aqueous Battery ◽  
Storage Batteries ◽  
Aqueous Batteries ◽  
Superior Level

AbstractElectrochemically reversible redox couples that embrace more electron transfer at a higher potential are the eternal target for energy storage batteries. Here, we report a four-electron aqueous zinc-iodine battery by activating the highly reversible I2/I+ couple (1.83 V vs. Zn/Zn2+) in addition to the typical I−/I2 couple (1.29 V). This is achieved by intensive solvation of the aqueous electrolyte to yield ICl inter-halogens and to suspend its hydrolysis. Experimental characterization and modelling reveal that limited water activity and sufficient free chloride ions in the electrolyte are crucial for the four-electron process. The merits of the electrolyte also afford to stabilize Zn anode, leading to a reliable Zn-I2 aqueous battery of 6000 cycles. Owing to high operational voltage and capacity, energy density up to 750 Wh kg−1 based on iodine mass was achieved (15–20 wt% iodine in electrode). It pushes the Zn-I2 battery to a superior level among these available aqueous batteries.

scholarly journals Ultralong π-Conjugated Bis(terpyridine)metal Polymer Wires Covalently Bound to a Carbon Electrode: Fast Redox Conduction and Redox Diode Characteristics

Molecules ◽  
2021 ◽  
Vol 26 (14) ◽  
pp. 4267
Author(s):  
Kuo-Hui Wu ◽  
Ryota Sakamoto ◽  
Hiroaki Maeda ◽  
Eunice Jia Han Phua ◽  
Hiroshi Nishihara
Keyword(s):  
Metal Complex ◽  
Electrochemical Method ◽  
Redox Reactions ◽  
Cyclic Voltammograms ◽  
Wire Arrays ◽  
Reversible Redox ◽  
Complex Linear ◽  
Complex Polymer ◽  
Metal Polymer ◽  
Hclo4 Solution

We developed an efficient and convenient electrochemical method to synthesize π-conjugated redox metal-complex linear polymer wires composed of azobenzene-bridged bis(terpyridine)metal (2-M, M = Fe, Ru) units covalently immobilized on glassy carbon (GC). Polymerization proceeds by electrochemical oxidation of bis(4′-(4-anilino)-2,2′:6′,2″-terpyridine)metal (1-M) in a water–acetonitrile–HClO4 solution, affording ultralong wires up to 7400 mers (corresponding to ca. 15 μm). Both 2-Fe and 2-Ru undergo reversible redox reactions, and their redox behaviors indicate remarkably fast redox conduction. Anisotropic hetero-metal-complex polymer wires with Fe and Ru centers are constructed via stepwise electropolymerization. The cyclic voltammograms of two hetero-metal-complex polymer wires, GC/[2-Fe]–[2-Ru] (3) and GC/[2-Ru]–[2-Fe] (4), show irreversible redox reactions with opposite electron transfer characteristics, indicating redox diodelike behavior. In short, the present electrochemical method is useful to synthesize polymer wire arrays and to integrate functional molecules on carbon.

Thermo-chemical water splitting: Selection of priority reversible redox reactions by multi-attribute decision making

2021 ◽  
Vol 170 ◽  
pp. 800-810
Author(s):  
Yimin Deng ◽  
Raf Dewil ◽  
Lise Appels ◽  
Shuo Li ◽  
Jan Baeyens ◽  
...  
Keyword(s):  
Decision Making ◽  
Water Splitting ◽  
Redox Reactions ◽  
Reversible Redox ◽  
Multi Attribute Decision Making ◽  
Chemical Water ◽  
Selection Of

The effect of pyrolysis on the chemical, thermal and rheological properties of pitch

Soft Matter ◽  
2021 ◽  
Vol 17 (39) ◽  
pp. 8925-8936
Author(s):  
Heedong Yoon ◽  
Zachary R. Hinton ◽  
James Heinzman ◽  
Clarence E. Chase ◽  
Manesh Gopinadhan ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Chemical Analysis ◽  
Rheological Properties ◽  
Clear Correlation ◽  
Aromatic Species

There is a clear correlation between pyrolysis time and the extensional properties of pitch. Chemical analysis shows an increase in aromatic species and a shift to higher molecular weight. We hypothesize that these results are important in understanding pitch spinnability.

Rational Design of Reversible Redox Shuttle for Highly Efficient Light-Driven Microswimmer

ACS Nano ◽  
2020 ◽  
Vol 14 (3) ◽  
pp. 3272-3280 ◽  
Author(s):  
Jizhuang Wang ◽  
Ze Xiong ◽  
Ming Liu ◽  
Xiao-meng Li ◽  
Jing Zheng ◽  
...  
Keyword(s):  
Rational Design ◽  
Highly Efficient ◽  
Reversible Redox ◽  
Redox Shuttle
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