Reference electrode for anhydrous dimethylformamide

Marple, L. W.

doi:10.1021/ac60251a014

Cited by 178 publications

(81 citation statements)

References 8 publications

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“…[32,33] All poten-tials are quoted with respect to a reference electrode consisting of a cadmium-saturated mercury amalgam in contact with DMF saturated with both cadmium chloride and sodium chloride; this electrode has a potential of -0.76 V vs. the aqueous saturated calomel electrode (SCE) at 25°C. [34,35] Separation, Identification, and Quantitation of Electrolysis Products: At the end of each controlled-potential electrolysis, the catholyte containing the products was partitioned between diethyl ether and water, and then the ether phase was dried with anhydrous magnesium sulfate, concentrated by means of rotary evaporation, and analyzed with the aid of either GC-MS or GC. First, we used GC-MS to identify all of the electrolysis products through a comparison of their gas chromatographic retention times and mass spectra with those of authentic reference compounds; a Hewlett-Packard 6890N gas chromatograph coupled with a Hewlett-Packard 5973 inert mass-selective detector was employed.…”

Section: Mechanistic Aspects Of the Nickel(i) Salen Catalyzed Reductimentioning

confidence: 99%

Catalytic Reduction of Phenyl‐Conjugated Acetylenic Halides by Nickel(I) Salen: Cyclization versus Coupling

et al. 2007

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Cyclic voltammetry and controlled-potential electrolysis were employed to study the catalytic reduction of five phenyl-conjugated haloalkynes by nickel(I) salen electrogenerated at carbon cathodes in dimethylformamide containing tetramethylammonium tetrafluoroborate. Electrocatalytic reduction of 7-bromo-and 7-iodo-1-phenyl-1-heptyne affords the carbocyclic product, benzylidenecyclohexane, in up to 41 % yield, whereas under similar conditions reduction of 5-halo-1-phenyl-1-pentyne and 8-bromo-1-phenyl-1-octyne gives benzylidenecyclobutane and benzylidenecycloheptane, respectively, in very low yield (Յ1 %). Dimers, alkynes, and alkenynes are other products formed from the phenyl-

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Section: Mechanistic Aspects Of the Nickel(i) Salen Catalyzed Reductimentioning

confidence: 99%

Catalytic Reduction of Phenyl‐Conjugated Acetylenic Halides by Nickel(I) Salen: Cyclization versus Coupling

et al. 2007

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“…• C. [26][27][28] Cells, instrumentation, and procedural details for cyclic voltammetry are described in previous publications. 6,29,30 For controlled-potential (bulk) electrolyses, working cathodes (with geometric areas of approximately 20 cm 2 ) were constructed from silver gauze (Alfa Aesar, 99.9%, 20-mesh, woven from 0.356-mm-diameter wire).…”

Section: Methodsmentioning

confidence: 99%

“…Finally, a very brief cathodic polarization of the electrode, after being inserted into the electrolysis cell, serves to activate the cathode completely. As indicated in the preceding paragraph, the reference electrode was a saturated cadmium amalgam in DMF; [26][27][28] the auxiliary anode was a graphite rod separated from the cathode compartment by a medium-porosity sintered-glass disk backed by a methyl cellulose-DMF-0.10 M TEABF 4 plug. Information about the two-compartment (divided) electrolysis cell, as well as details about instrumentation and procedures for bulk electrolyses, can be found in earlier papers.…”

Section: Methodsmentioning

confidence: 99%

Electrochemical Reduction of a Bromo Propargyloxy Ester at Silver Cathodes in Dimethylformamide

Henderson

Buehler

Pasciak

et al. 2014

J. Electrochem. Soc.

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Cyclic voltammograms for the reduction of ethyl 2-bromo-3-(3 ,4 -dimethoxyphenyl)-3-(propargyloxy)propanoate (1) at a silver cathode in dimethylformamide (DMF) containing 0.10 M tetraethylammonium tetrafluoroborate (TEABF 4 ) exhibit several cathodic peaks, the first of which is attributed to reductive cleavage of the carbon-bromine bond. Controlled-potential (bulk) electrolyses of 1 at silver gauze electrodes in DMF-0.10 M TEABF 4 give rise to four products: cis-and trans-isomers of ethyl 3-(3 ,4 -dimethoxyphenyl)-prop-2-enoate (4), ethyl 3-(3 ,4 -dimethoxyphenyl)propiolate (7), and ethyl 3-(3 ,4 -dimethoxyphenyl)-3-(prop-2-yn-1-yloxy)propanoate (8). These products have been identified with the aid of mass spectrometry and nuclear magnetic resonance spectroscopy. We propose that reduction of 1 involves two-electron cleavage of the carbon-bromine bond to form a carbanion. Then the latter species eliminates − OCH 2 C≡CH to afford 4. In addition, − OCH 2 C≡CH can deprotonate 1 to yield (Z)-ethyl 2-bromo-3-(3 ,4 -dimethoxyphenyl)acrylate (5), which is further deprotonated by − OCH 2 C≡CH to give 7. Alternatively, the carbanion resulting from the original two-electron reduction of 1 can gain a proton from the medium to form 8. In two previous projects 1,2 involving collaboration with our laboratory, electrochemical methods were probed as an avenue to the synthesis of building blocks for lignans, which comprise a class of phenylalanine-derived compounds that have attracted considerable attention due to their pharmacological activity and abundance in nature. In the first of those investigations, 1 we examined the reductive intramolecular cyclization of ethyl 2-bromo-3-(3 ,4 -dimethoxyphenyl)-3-(propargyloxy)propanoate (1), catalyzed by electrogenerated nickel(I) tetramethylcyclam, to afford 2-(3 ,4 -dimethoxyphenyl)-3-(ethoxycarbonyl)-4-methylenetetrahydrofuran (2) in good yield (72-85%); the latter species is a desired precursor for the formation of isogmelinol (a furofuran lignan). In addition, a second product, 2-(3 ,4 -dimethoxyphenyl)-3-ethoxycarbonyl-4-methyl-2,5-dihydrofuran (3), was obtained in significant yield (22-30%).A second paper 2 was concerned with the direct reduction of 1 at both glassy carbon and reticulated vitreous carbon cathodes in dimethylformamide (DMF) containing various tetraalkylammonium salts. Interestingly, although 2 was not obtained, 3 (which * Electrochemical Society Student Member.* * Electrochemical Society Fellow. z E-mail: peters@indiana.edu arises via base-promoted rearrangement of 2) was found in modest yield (18-26%). More importantly, the principal product was ethyl trans-3-(3 ,4 -dimethoxyphenyl)acrylate (4), although small amounts of (Z)-ethyl 2-bromo-3-(3 ,4 -dimethoxyphenyl)acrylate (5) and ethyl 3-(3 ,4 -dimethoxyphenyl)-2,3-bis(prop-2-yn-1-yloxy)propanoate (6) were detected.Recent publications from our laboratory 3-8 and by other research groups 9-24 have dealt with the electrochemistry of halogenated organic compounds at silver cathodes and have revealed the catalytic ef...

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“…Customized 2.4 cm diameter × 0.4 cm thick reticulated vitreous carbon disks (Duocel RVC 100 PPI, Energy Research and Generation) were used as working cathodes for CPE; these disks were cleaned and handled according to established procedures. 16 The reference electrode consists of a cadmium-saturated mercury amalgam in contact with DMF saturated with both cadmium chloride and sodium chloride 17,18 Ni II + e _ e . ultraviolet-visible detector (set at 254 nm), and a SUPELCOSIL LC-18 analytical HPLC column (15 cm × 4.6 mm, 3 μm particle size) was used to detect the nickel(II) salens in electrolyzed solutions.…”

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confidence: 99%

Reaction Mechanism for the Formation of Dialkylated Nickel(II) Salen Involved in the Catalytic Reduction of (Bromomethyl)cyclopropane

Lambert

Enters

Rastogi

et al. 2016

J. Electrochem. Soc.

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Cyclic voltammetry (CV) and controlled-potential electrolysis (CPE) were employed to examine the reaction between electrogenerated ligand-reduced nickel(II) salen and (bromomethyl)cyclopropane. Cyclic voltammograms for nickel(II) salen in the presence of (bromomethyl)cyclopropane exhibit characteristic features for the catalytic reduction of the substrate. Bulk electrolyses of (bromomethyl)cyclopropane at carbon cathodes in dimethylformamide catalyzed by nickel(II) salen were carried out to investigate the mechanism for the formation of dialkylated nickel(II) salen, which was analyzed and identified by high-performance liquid chromatography (HPLC). The corresponding dialkylated nickel(II) salen was further purified and collected by preparative-scale HPLC. Its complete structure was revealed by electrospray-ionization mass spectrometry (ESI-MS), 1 H NMR, COSY, and HECTOR NMR spectrometry. The clear-cut reaction mechanism for its formation was proposed on the basis of current and previous studies.

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Reference electrode for anhydrous dimethylformamide

Cited by 178 publications

References 8 publications

Catalytic Reduction of Phenyl‐Conjugated Acetylenic Halides by Nickel(I) Salen: Cyclization versus Coupling

Catalytic Reduction of Phenyl‐Conjugated Acetylenic Halides by Nickel(I) Salen: Cyclization versus Coupling

Electrochemical Reduction of a Bromo Propargyloxy Ester at Silver Cathodes in Dimethylformamide

Reaction Mechanism for the Formation of Dialkylated Nickel(II) Salen Involved in the Catalytic Reduction of (Bromomethyl)cyclopropane

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