scholarly journals Bis(vinylenedithio)tetrathiafulvalene analogues of BEDT-TTF

2015 ◽  
Vol 11 ◽  
pp. 403-415 ◽  
Author(s):  
Erdal Ertas ◽  
İlknur Demirtas ◽  
Turan Ozturk
Keyword(s):  
Electron Donor ◽  
Electron Donors ◽  
Electron Delocalization ◽  
Current Status ◽  
Phenyl Rings

This review aims to give an overview of the current status of our research on the synthesis of π-electron donor bis(ethylenedithio)tetrathiafulvalene (BEDT-TTF, ET) analogues prepared from 1,8-diketones via a ring forming reaction. The new synthesized π-electron donors have vinyl moieties producing extended π-electron delocalization over the substituent phenyl rings at the peripheries.

Acyclic versus cyclic π-electron delocalization. How is the substituent effect related to π-electron delocalization?

2009 ◽  
Vol 74 (1) ◽  
pp. 115-129 ◽  
Author(s):  
Michał A. Dobrowolski ◽  
Jędrzej Kaniewski ◽  
Tadeusz M. Krygowski ◽  
Michał K. Cyrański
Keyword(s):  
Electron Donor ◽  
Electron Acceptor ◽  
Substituent Effect ◽  
Electron Donors ◽  
Electron Delocalization ◽  
Benzene Derivatives ◽  
Phenol Derivatives ◽  
Stabilization Energies ◽  
Derivatives Of ◽  
Substituted 1

Substituent effect stabilization energies were estimated for sets of 27 para-substituted phenol derivatives, meta- and para-homodisubstituted benzene derivatives, trans-substituted ethenes, 4-substituted 1-hydroxy-1,3-cyclohexadienes and 1,4-homodisubstituted 1,3-cyclohexadienes based on the optimizations at the B3LYP/6-311+G** DFT level of theory. The following substituents were taken into account: C≡CH, C(CN)3, CF3, CH2NH2, CH3, CH=CH2, CHO, Cl, CN, COCH3, COCl, CONH2, COOCH3, COOH, F, NH2, NHCH3, N(CH3)2, NHOH, NO, NO2, OCH3, OH, Ph, H, SH, SO2CN. For hydroxyethenes and phenol derivatives the electron-acceptor substituents stabilize the systems, whereas the electron-donors lead to their destabilization. Both electron-acceptor and electron-donor substituents destabilize homodisubstituted ethene and meta- and para-homodisubstituted benzene species. The strongest destabilization is observed for derivatives of ethene, a weaker one for derivatives of cyclohexadiene and the weakest for benzene derivatives.

scholarly journals A Microcosm Treatability Study for Evaluating Wood Mulch-Based Amendments as Electron Donors for Trichloroethene (TCE) Reductive Dechlorination

Water ◽  
2021 ◽  
Vol 13 (14) ◽  
pp. 1949
Author(s):  
Edoardo Masut ◽  
Alessandro Battaglia ◽  
Luca Ferioli ◽  
Anna Legnani ◽  
Carolina Cruz Viggi ◽  
...  
Keyword(s):  
Electron Donor ◽  
Environmental Sustainability ◽  
Reductive Dechlorination ◽  
Environmental Remediation ◽  
Low Cost ◽  
Chlorinated Solvents ◽  
Electron Donors ◽  
Chlorinated Ethenes ◽  
Dehalococcoides Mccartyi ◽  
Wood Mulch

In this study, wood mulch-based amendments were tested in a bench-scale microcosm experiment in order to assess the treatability of saturated soils and groundwater from an industrial site contaminated by chlorinated ethenes. Wood mulch was tested alone as the only electron donor in order to assess its potential for stimulating the biological reductive dechlorination. It was also tested in combination with millimetric iron filings in order to assess the ability of the additive to accelerate/improve the bioremediation process. The efficacy of the selected amendments was compared with that of unamended control microcosms. The results demonstrated that wood mulch is an effective natural and low-cost electron donor to stimulate the complete reductive dechlorination of chlorinated solvents to ethene. Being a side-product of the wood industry, mulch can be used in environmental remediation, an approach which perfectly fits the principles of circular economy and addresses the compelling needs of a sustainable and low environmental impact remediation. The efficacy of mulch was further improved by the co-presence of iron filings, which accelerated the conversion of vinyl chloride into the ethene by increasing the H2 availability rather than by catalyzing the direct abiotic dechlorination of contaminants. Chemical analyses were corroborated by biomolecular assays, which confirmed the stimulatory effect of the selected amendments on the abundance of Dehalococcoides mccartyi and related reductive dehalogenase genes. Overall, this paper further highlights the application potential and environmental sustainability of wood mulch-based amendments as low-cost electron donors for the biological treatment of chlorinated ethenes.

Microbial Perchlorate Reduction in Groundwater with Different Electron Donors

2013 ◽  
Vol 295-298 ◽  
pp. 1402-1407
Author(s):  
Rui Wang ◽  
Ming Chen ◽  
Jia Wen Zhang ◽  
Fei Liu ◽  
Hong Han Chen
Keyword(s):  
Removal Efficiency ◽  
Electron Donor ◽  
Electron Acceptor ◽  
Reduction Rate ◽  
Electron Donors ◽  
Monod Equation ◽  
Hydrogen Addition ◽  
Perchlorate Reduction ◽  
Perchlorate Removal

Effects of different electron donors (acetate and hydrogen), acetate and perchlorate concentrations on microbial perchlorate reduction in groundwater were studied. The results showed that acetate and hydrogen addition as an electron donor can significantly improve perchlorate removal efficiency while a longer period was observed for hydrogen (15 d) than for acetate (8 d). The optical ratio of electron donor (acetate)-to-electron acceptor (perchlorate) was approximately 1.65 mg COD mg perchlorate-1. The highest specific reduction rate of perchlorate was achieved at the acetate-to-perchlorate ratio of 3.80 mg COD mg perchlorate-1. The perchlorate reduction rates corresponded well to the theoretical values calculated by the Monod equation and the parameters of Ks and Vm were determined to be 15.6 mg L-1 and 0.26 d-1, respectively.

Photocatalytic CO2 reduction using water as an electron donor by a powdered Z-scheme system consisting of metal sulfide and an RGO–TiO2 composite

2017 ◽  
Vol 198 ◽  
pp. 397-407 ◽  
Author(s):  
Tomoaki Takayama ◽  
Ko Sato ◽  
Takehiro Fujimura ◽  
Yuki Kojima ◽  
Akihide Iwase ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Graphene Oxide ◽  
Visible Light ◽  
Water Splitting ◽  
Electron Donor ◽  
Visible Light Irradiation ◽  
Co2 Reduction ◽  
Metal Sulfide ◽  
Electron Donors ◽  
Reduced Graphene

CuGaS2, (AgInS2)x–(ZnS)2−2x, Ag2ZnGeS4, Ni- or Pb-doped ZnS, (ZnS)0.9–(CuCl)0.1, and ZnGa0.5In1.5S4 showed activities for CO2 reduction to form CO and/or HCOOH in an aqueous solution containing K2SO3 and Na2S as electron donors under visible light irradiation. Among them, CuGaS2 and Ni-doped ZnS photocatalysts showed relatively high activities for CO and HCOOH formation, respectively. CuGaS2 was applied in a powdered Z-scheme system combining with reduced graphene oxide (RGO)-incorporated TiO2 as an O2-evolving photocatalyst. The powdered Z-scheme system produced CO from CO2 in addition to H2 and O2 due to water splitting. Oxygen evolution with an almost stoichiometric amount indicates that water was consumed as an electron donor in the Z-schematic CO2 reduction. Thus, we successfully demonstrated CO2 reduction of artificial photosynthesis using a simple Z-scheme system in which two kinds of photocatalyst powders (CuGaS2 and an RGO–TiO2 composite) were only dispersed in water under 1 atm of CO2.

ELECTRON DONORS AND COFAGTORS FOR DENITRIFIGATION BY PSEUDOMONAS PERFECTOMARINUS

1963 ◽  
Vol 9 (6) ◽  
pp. 799-807 ◽  
Author(s):  
Martha Rhodes ◽  
Audrey Best ◽  
W. J. Payne
Keyword(s):  
Amino Acids ◽  
Electron Donor ◽  
Electron Donors ◽  
Resting Cells ◽  
Test Compound ◽  
Whole Cell ◽  
Minimal Media

Pseudomonas perfectomarinus released nitrogen fiom nitrate in media containing a variety of amino acids, pyruvate, or urea, but only if these minimal media were supplemented with glucose or, preferably, citrate. L-Arabinose (and to a lesser degree, D-arabinose) served as electron donor in combination with glucose or citrate, whereas other sugars did not. Asparagine, however, was the most effective oxidizable substrate tested and was the only test compound supporting denitrification without supplementary glucose or citrate. Mano-metric experiments revealed that adapted resting cells liberated nitrogen very rapidly with asparagine but less rapidly with citrate. Furthermore, cell-free extracts of adapted bacteria denitrified nitrate when provided with these substrates. Flavine mononucleotide was more effective as a stimulatory cofactor for denitrification than flavine adenine dinucleotide in whole-cell experiments, but not with cell-free extracts. Experiments with dialyzed cell-free extracts revealed that the enzymes which oxidized asparagine and citrate (or actually isocitrate) were linked with triphosphopyridine nucleotide. Additional experiments with cell-free extracts revealed that oxidation of reduced triphosphopyridine nucleotide was enzymatically linked with flavine mononucleotide.

scholarly journals Diversity and Ubiquity of Bacteria Capable of Utilizing Humic Substances as Electron Donors for Anaerobic Respiration

2002 ◽  
Vol 68 (5) ◽  
pp. 2445-2452 ◽  
Author(s):  
John D. Coates ◽  
Kimberly A. Cole ◽  
Romy Chakraborty ◽  
Susan M. O'Connor ◽  
Laurie A. Achenbach
Keyword(s):  
Energy Source ◽  
Carbon Source ◽  
Humic Substances ◽  
Electron Donor ◽  
Electron Acceptor ◽  
Electron Donors ◽  
16S Rrna Genes ◽  
Rrna Genes ◽  
Couple Growth ◽  
Probable Number

ABSTRACT Previous studies have demonstrated that reduced humic substances (HS) can be reoxidized by anaerobic bacteria such as Geobacter, Geothrix, and Wolinella species with a suitable electron acceptor; however, little is known of the importance of this metabolism in the environment. Recently we investigated this metabolism in a diversity of environments including marine and aquatic sediments, forest soils, and drainage ditch soils. Most-probable-number enumeration studies were performed using 2,6-anthrahydroquinone disulfonate (AHDS), an analog for reduced HS, as the electron donor with nitrate as the electron acceptor. Anaerobic organisms capable of utilizing reduced HS as an electron donor were found in all environments tested and ranged from a low of 2.31 × 101 in aquifer sediments to a high of 9.33 × 106 in lake sediments. As part of this study we isolated six novel organisms capable of anaerobic AHDS oxidation. All of the isolates coupled the oxidation of AHDS to the reduction of nitrate with acetate (0.1 mM) as the carbon source. In the absence of cells, no AHDS oxidation was apparent, and in the absence of AHDS, no cell density increase was observed. Generally, nitrate was reduced to N2. Analysis of the AHDS and its oxidized form, 2,6-anthraquinone disulfonate (AQDS), in the medium during growth revealed that the anthraquinone was not being biodegraded as a carbon source and was simply being oxidized as an energy source. Determination of the AHDS oxidized and nitrate reduced accounted for 109% of the theoretical electron transfer. In addition to AHDS, all of these isolates could also couple the oxidation of reduced humic substances to the reduction of nitrate. No HS oxidation occurred in the absence of cells and in the absence of a suitable electron acceptor, demonstrating that these organisms were capable of utilizing natural HS as an energy source and that AHDS serves as a suitable analog for studying this metabolism. Alternative electron donors included simple volatile fatty acids such as propionate, butyrate, and valerate as well as simple organic acids such as lactate and pyruvate. Analysis of the complete sequences of the 16S rRNA genes revealed that the isolates were not closely related to each other and were phylogenetically diverse, with members in the alpha, beta, gamma, and delta subdivisions of the Proteobacteria. Most of the isolates were closely related to known genera not previously recognized for their ability to couple growth to HS oxidation, while one of the isolates represented a new genus in the delta subclass of the Proteobacteria. The results presented here demonstrate that microbial oxidation of HS is a ubiquitous metabolism in the environment. This study represents the first description of HS-oxidizing isolates and demonstrates that microorganisms capable of HS oxidation are phylogenetically diverse.

scholarly journals Dissimilatory Arsenate Reduction with Sulfide as Electron Donor: Experiments with Mono Lake Water and Isolation of Strain MLMS-1, a Chemoautotrophic Arsenate Respirer

2004 ◽  
Vol 70 (5) ◽  
pp. 2741-2747 ◽  
Author(s):  
Shelley E. Hoeft ◽  
Thomas R. Kulp ◽  
John F. Stolz ◽  
James T. Hollibaugh ◽  
Ronald S. Oremland
Keyword(s):  
Electron Donor ◽  
Lake Water ◽  
Electron Donors ◽  
Mono Lake ◽  
Arsenate Reduction ◽  
Curved Rod ◽  
Gene Probing ◽  
Rrna Sequences ◽  
16S Rrna Sequences

ABSTRACT Anoxic bottom water from Mono Lake, California, can biologically reduce added arsenate without any addition of electron donors. Of the possible in situ inorganic electron donors present, only sulfide was sufficiently abundant to drive this reaction. We tested the ability of sulfide to serve as an electron donor for arsenate reduction in experiments with lake water. Reduction of arsenate to arsenite occurred simultaneously with the removal of sulfide. No loss of sulfide occurred in controls without arsenate or in sterilized samples containing both arsenate and sulfide. The rate of arsenate reduction in lake water was dependent on the amount of available arsenate. We enriched for a bacterium that could achieve growth with sulfide and arsenate in a defined, mineral medium and purified it by serial dilution. The isolate, strain MLMS-1, is a gram-negative, motile curved rod that grows by oxidizing sulfide to sulfate while reducing arsenate to arsenite. Chemoautotrophy was confirmed by the incorporation of H14CO3 − into dark-incubated cells, but preliminary gene probing tests with primers for ribulose-1,5-biphosphate carboxylase/oxygenase did not yield PCR-amplified products. Alignment of 16S rRNA sequences indicated that strain MLMS-1 was in the δ-Proteobacteria, located near sulfate reducers like Desulfobulbus sp. (88 to 90% similarity) but more closely related (97%) to unidentified sequences amplified previously from Mono Lake. However, strain MLMS-1 does not grow with sulfate as its electron acceptor.

Electrical properties of crystal compounds of graphite - III. The role of electron donors

1960 ◽  
Vol 258 (1294) ◽  
pp. 339-349 ◽  
Keyword(s):  
Alkali Metal ◽  
Thermoelectric Power ◽  
Electron Donor ◽  
Electron Acceptor ◽  
Electrical Resistance ◽  
Pyrolytic Graphite ◽  
Electron Donors ◽  
Aluminium Chloride ◽  
Metal Atoms ◽  
Donor And Acceptor

Crystal compounds between potassium and well-oriented pyrolytic graphite have been prepared with a range of compositions up to saturation. Measurements have been made of changes of electrical resistance and of thermoelectric power as a function of composition in both a - and c -axis directions. Anisotropy of electrical resistance becomes smaller, and of thermoelectric power sinks to practically zero, on compound formation. Compounds between graphite and rubidium or caesium have been studied more briefly under conditions approximating to saturation. In the direction of the a -axis, the large decreases of electrical resistance observed can be interpreted on the basis that the alkali metal atoms inject electrons into the upper π -band of graphite. This is confirmed by the observed changes of thermoelectric power. Changes resemble but do not completely mirror those observed with electron acceptor compounds; the fractional transfer of electrons appears to be less complete with the electron donors. In the direction of the c -axis, intercalation of the electron donor alkali metal atoms leads to a much more striking decrease of electrical resistance than is observed with various electron acceptor groups. To supplement results previously published, brief studies are reported on crystal compounds between graphite and aluminium chloride, and graphite and iodine monochloride. Possible band models for graphite compounds with both electron donor and acceptor atoms are discussed in the light of the experimental findings.

scholarly journals Hexavalent Chromate Reductase Activity in Cell Free Extracts ofPenicilliumsp.

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Damaris L. Arévalo-Rangel ◽  
Juan F. Cárdenas-González ◽  
Víctor M. Martínez-Juárez ◽  
Ismael Acosta-Rodríguez
Keyword(s):  
Metal Ions ◽  
Hexavalent Chromium ◽  
Electron Donor ◽  
Reductase Activity ◽  
Electron Donors ◽  
Cell Free Extract ◽  
Optimal Temperature ◽  
Chromate Reductase

A chromium-resistant fungus isolated from contaminated air with industrial vapors can be used for reducing toxic Cr(VI) to Cr(III). This study analyzes in vitro reduction of hexavalent chromium using cell free extract(s) of the fungus that was characterized based on optimal temperature, pH, use of electron donors, metal ions and initial Cr(VI) concentration in the reaction mixture. This showed the highest activity at 37°C and pH 7.0; there is an increase in Cr(VI) reductase activity with addition of NADH as an electron donor, and it was highly inhibited by Hg2+, Ca2+and Mg2+, and azide, EDTA, and KCN.

scholarly journals Kinetic studies on the hydroxylation of p-coumaric acid to caffeic acid by spinach-beet phenolase

1975 ◽  
Vol 149 (2) ◽  
pp. 447-461 ◽  
Author(s):  
R J McIntyre ◽  
P F T. Vaughan
Keyword(s):  
Caffeic Acid ◽  
Electron Donor ◽  
Active Site ◽  
Initial Velocity ◽  
Kinetic Studies ◽  
Reaction Scheme ◽  
Spectrophotometric Assay ◽  
Electron Donors ◽  
Coumaric Acid ◽  
Substrate Addition

1. A spectrophotometric assay is described that enables the hydroxylation of p-coumaric acid to caffeic acid, catalysed by spinach-beet phenolase, to be followed continuously. 2. Initial-velocity and inhibitor studies indicate that the order of substrate addition is oxygen, p-coumaric acid and electron donor, with an irreversible step separating the binding of each substrate. 3. Caffeic acid is most likely to act as electron donor at the active site; other electron donors, such as ascorbic acid, NADH and dimethyltetrahydropteridine, function mainly to recycle cofactor amounts of caffeic acid. 4. A reaction scheme, consistent with these data, is proposed.

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