scholarly journals Facile preparation and isolation of neutral organic electron donors based on 4-dimethylaminopyridine

2018 ◽  
Vol 96 (6) ◽  
pp. 522-525 ◽  
Author(s):  
Julien D. Martin ◽  
C. Adam Dyker
Keyword(s):  
Electron Transfer ◽  
Cyclic Voltammetry ◽  
Inert Atmosphere ◽  
Electron Donors ◽  
High Yield ◽  
Step Procedure ◽  
Organic Electron ◽  
Facile Preparation ◽  
Isolated Neutral

A number of new neutral bis-2-(4-dimethylamino)pyridinylidene electron donors featuring N-akyl groups of varying lengths (propyl, butyl, hexyl, dodecyl) have been prepared from 4-dimethylaminopyridine by means of a simple two-step procedure. Each derivative could be isolated in high yield and could be stored indefinitely under inert atmosphere. The electron donors were chemically oxidized to the corresponding bipyridinium ions, and all compounds were characterized by NMR spectroscopy and cyclic voltammetry. As an emerging class of electron transfer agents, the availability of the isolated neutral bispyridinylidenes should be beneficial for cases that are incompatible with generating the electron donor in situ.

scholarly journals Dual Roles for Potassium Hydride in Haloarene Reduction: CSNAr and Single Electron Transfer Reduction via Organic Electron Donors Formed in Benzene

2018 ◽  
Vol 140 (36) ◽  
pp. 11510-11518 ◽  
Author(s):  
Joshua P. Barham ◽  
Samuel E. Dalton ◽  
Mark Allison ◽  
Giuseppe Nocera ◽  
Allan Young ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Electron Donors ◽  
Single Electron ◽  
Single Electron Transfer ◽  
Dual Roles ◽  
Organic Electron ◽  
Potassium Hydride

Photolysis of water for H 2 production with the use of biological and artificial catalysts

1980 ◽  
Vol 295 (1414) ◽  
pp. 473-476 ◽  
Keyword(s):  
Aqueous Solution ◽  
Electron Transfer ◽  
Bovine Serum Albumin ◽  
Bovine Serum ◽  
Methyl Viologen ◽  
Electron Donors ◽  
Organic Electron ◽  
Aqueous Mixture ◽  
The Stability ◽  
Electron Carriers

An aqueous mixture of chloroplasts, hydrogenase and an electron transfer catalyst on illumination liberates H 2 , the source of the H atoms being water. The rate and duration of H 2 production from such a system depends on the stability of chloroplast and hydrogenase activities in light and oxygen. Both chloroplasts and hydrogenases can be stabilized to a certain degree by immobilization in gels or by incubation in bovine serum albumin. Natural electron carriers of hydrogenases are ferredoxin, cytochrome c 3 and NAD. Viologen dyes and synthetic iron-sulphur particles (Jeevanu) can substitute for the biological carriers. Methyl viologen, photoreduced in the presence of chloroplasts, can liberate H 2 in combination with Pt (Adam’s catalyst). An aqueous solution of proflavine can be photoreduced in the presence of organic electron donors such as EDTA, cysteine, dithiothreitol, etc.; the reduced proflavine can subsequently liberate H 2 with MV-Pt, MV-hydrogenase, ferredoxin-hydrogenase or cytochrome-hydrogenase systems.

scholarly journals Generation of powerful organic electron donors by water-assisted decarboxylation of benzimidazolium carboxylates

2021 ◽  
Author(s):  
Guillaume Tintori ◽  
Arona Fall ◽  
Nadhrata Assani ◽  
Yuxi Zhao ◽  
David Bergé-Lefranc ◽  
...  
Keyword(s):  
Radical Addition ◽  
Electron Donors ◽  
Addition Reactions ◽  
Organic Electron ◽  
Water Activation

In situ and easy generation of organic electron donors from water-activation of carboxylate precursors allows OED-promoted intermolecular radical addition reactions.

Iodosulfonation of alkenes with benzenesulfinic acid – N-iodosuccinimide — Facile preparation of α,β-unsaturated sulfones

2006 ◽  
Vol 84 (4) ◽  
pp. 667-675 ◽  
Author(s):  
Russell R Wolff ◽  
Vikram Basava ◽  
Robert M Giuliano ◽  
Walter J Boyko ◽  
J Herman Schauble
Keyword(s):  
Room Temperature ◽  
High Yield ◽  
Allylic Alcohols ◽  
Neutral Alumina ◽  
Silyl Ethers ◽  
Step Procedure ◽  
Ferrier Rearrangement ◽  
Facile Preparation ◽  
High Yields ◽  
Yield And Purity

Reaction of alkenes and alkenols with N-iodosuccinimide (NIS) and benzenesulfinic acid in dichloromethane at room temperature affords vic-iodophenylsulfonyl adducts in good to high yields. Treatment of the iodosulfones with neutral alumina in dichloromethane at room temperature results in dehydroiodination to give the corresponding vinyl sulfones in high yield and purity by this convenient two-step procedure. Application of the iodosulfonation–dehydroiodination sequence to allylic alcohols and silyl ethers gave γ-oxygenated, α,β-unsaturated phenylsulfones, while the attempted iodosulfonation of glycals, as intermediates to vinyl sulfones, resulted in addition of benzenesulfinic acid with double bond shift (Ferrier rearrangement). Key words: iodosulfonation, vinyl sulfones, benzenesulfinic acid, N-iodosuccinimide, dehydroiodination.

The Improved Synthesis of Boc-Abu(PO3Me2)-OH and Its Use for the Facile Synthesis of Glu-Abu(P)-Leu

1992 ◽  
Vol 45 (8) ◽  
pp. 1225 ◽  
Author(s):  
G Tong ◽  
JW Perich ◽  
RB Johns
Keyword(s):  
Trifluoroacetic Acid ◽  
Optical Purity ◽  
High Yield ◽  
Facile Synthesis ◽  
Tributyltin Hydride ◽  
Step Procedure ◽  
Sodium Borohydride Reduction ◽  
Methyl Phosphate ◽  
Phosphate Groups

The improved synthesis of Boc -L-Abu(PO3Me2)-OH from Boc-Asp-Obut in 42% overall yield is described. This derivative was prepared in seven steps and involved initial sodium borohydride reduction of the isobutoxycarbonyl mixed anhydride of BOC-Asp-OBut and subsequent 2,2,6,6- tetramethylpiperidine-1-oxyl-catalysed sodium hypochlorite oxidation of the alcohol. The resultant aldehyde was phosphonylated by reflux with dimethyl trimethylsilyl phosphite and the trimethylsilyl group was then cleaved in situ by aqueous hydrolysis. The 4-hydroxy 4-dimethylphosphono derivative was converted into the Abu(PO3Me2) residue by reaction with thiocarbonyldiimidazole followed by radical deoxygenation of the thiocarbonylimidazolide with tributyltin hydride. The Boc and t-butyl groups were cleaved from BOC-Abu(PO3Me2)-OBut with trifluoroacetic acid and the Boc group was reintroduced to CF3CO2H.H-Abu(PO2Me2)-OH by using di-t-butyl dicarbonate to give Boc -Abu(PO3Me2)-OH as a clear oil. The optical purity of the Abu(PO3Me2) residue was established to be greater than 99.5% of the L-isomer by h.p.1.c. analysis of its L- Leu dipeptide. The protected derivative Boc-Abu(PO3Me2)-OH was used in the Boc mode of peptide synthesis for the preparation of Boc-Glu (OBz1)-Abu(PO3Me2)-Leu-OBzl in high yield, 40% CF3CO2H/CH2Cl2 being used for cleavage of the Boc group from intermediate peptides. The tripeptide was deprotected to CF3CO2H.H-Glu-Abu(P)- Leu -OH by a two-step procedure which involved initial hydrogenolytic cleavage of the benzyl groups in 50% CF3CO2H/CH3CO2H followed by cleavage of the methyl phosphate groups with either (A) 30% bromotrimethylsilane in acetonitrile, or (B) 1 M bromotrimethylsilane /l M thioanisole in trifluoroacetic acid; complete cleavage of the methyl groups was effected after 40 min and 12 h, respectively. In addition, the dipeptide Boc-Leu-Abu (P03Me2)- OBut was prepared from Boc-Abu(PO3Me2)-OBut in high yield and was readily deprotected by acidolytic cleavage of the t-butyl groups with trifluoroacetic acid followed by silylitic cleavage of the methyl phosphonate groups with 30% bromotrimethylsilane in acetonitrile, CF3CO2H.H-Leu-Abu(P)-OH being obtained in high yield.

Ground State Cross-Coupling of Haloarenes with Arenes Initiated by Organic Electron Donors, Formed in situ: An Overview

Synthesis ◽  
2019 ◽  
Vol 52 (03) ◽  
pp. 327-336 ◽  
Author(s):  
Giuseppe Nocera ◽  
John A. Murphy
Keyword(s):  
Coupling Reaction ◽  
Organic Additive ◽  
Electron Donors ◽  
Aromatic Substitution ◽  
Organic Additives ◽  
Aryl Radical ◽  
Wide Range ◽  
Homolytic Aromatic Substitution ◽  
Organic Electron

Many reactions have been discovered that lead to coupling of haloarenes to arenes using potassium tert-butoxide as the base, and one of a variety of organic compounds as an additive. The organic additive reacts with the base to form a strong organic electron donor in situ that initiates a base-induced homolytic aromatic substitution (BHAS) coupling reaction, by converting the haloarene into an aryl radical. This brief report presents an overview of the wide range of organic additives that can be used, and the organic electron donors that they form.

Synthesis, spectroscopy and electrochemistry of octaphenoxyphthalocyaninato silicon complexes

2001 ◽  
Vol 05 (07) ◽  
pp. 555-563 ◽  
Author(s):  
M. DAVID MAREE ◽  
TEBELLO NYOKONG
Keyword(s):  
Electron Transfer ◽  
Cyclic Voltammetry ◽  
Organic Solvents ◽  
High Yield ◽  
Cyclic Voltammograms ◽  
H Nmr ◽  
Axial Ligands ◽  
Convenient Route ◽  
Cyclic Voltammetry Data

A number of octaphenoxyphthalocyaninato silicon complexes containing a variety of axial ligands, represented by ( OPh )8 PcSi ( X )2 (where X = chloro 3, hydroxy 4, (4-carboxybenzene) acetato 5, isonicatinato 6, propionato 7, nitrophenoxy 8 and dimethylaminoxy 9) have been synthesized using a convenient route starting with the 4,5-diphenoxy-1,2-dicyanobenzene. 1 H NMR and UV/vis spectra, and the cyclic voltammetry of the complexes are reported. The complexes are obtained in high yield and are soluble in many organic solvents. Cyclic voltammetry revealed two reduction couples and one oxidation couple for these complexes. Analysis of the cyclic voltammograms showed that compounds 6 and 8 were easier to oxidize and more difficult to reduce than the rest. Also cyclic voltammetry data suggested that electron transfer was not governed only by diffusion.

scholarly journals Semiquantitative Detection of Hydrogen-Associated or Hydrogen-Free Electron Transfer within Methanogenic Biofilm of Microbial Electrosynthesis

2020 ◽  
Vol 86 (17) ◽  
Author(s):  
Weiwei Cai ◽  
Wenzong Liu ◽  
Bo Wang ◽  
Hong Yao ◽  
Awoke Guadie ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Cyclic Voltammetry ◽  
Value Added ◽  
Combination Method ◽  
Methane Generation ◽  
Microbial Electrosynthesis ◽  
Electrochemical Technology ◽  
Insight Into

ABSTRACT Hydrogen-entangled electron transfer has been verified as an important extracellular pathway of sharing reducing equivalents to regulate biofilm activities within a diversely anaerobic environment, especially in microbial electrosynthesis systems. However, with a lack of useful methods for in situ hydrogen detection in cathodic biofilms, the role of hydrogen involvement in electron transfer is still debatable. Here, a cathodic biofilm was constructed in CH4-produced microbial electrosynthesis reactors, in which the hydrogen evolution dynamic was analyzed to confirm the presence of hydrogen-associated electron transfer near the cathode within a micrometer scale. Fluorescent in situ hybridization images indicated that a colocalized community of archaea and bacteria developed within a 58.10-μm-thick biofilm at the cathode, suggesting that the hydrogen gradient detected by the microsensor was consumed by the collaboration of bacteria and archaea. Coupling of a microsensor and cyclic voltammetry test further provided semiquantitative results of the hydrogen-associated contribution to methane generation (around 21.20% ± 1.57% at a potential of −0.5 V to −0.69 V). This finding provides deep insight into the mechanism of electron transfer in biofilm on conductive materials. IMPORTANCE Electron transfer from an electrode to biofilm is of great interest to the fields of microbial electrochemical technology, bioremediation, and methanogenesis. It has a promising potential application to boost more value-added products or pollutant degradation. Importantly, the ability of microbes to obtain electrons from electrodes and utilize them brings new insight into direct interspecies electron transfer during methanogenesis. Previous studies verified the direct pathway of electron transfer from the electrode to a pure-culture bacterium, but it was rarely reported how the methanogenic biofilm of mixed cultures shares electrons by a hydrogen-associated or hydrogen-free pathway. In the current study, a combination method of microsensor and cyclic voltammetry successfully semiquantified the role of hydrogen in electron transfer from an electrode to methanogenic biofilm.

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