Oxidation by Cupric Ion

Nigh, W. G.

doi:10.1016/b978-0-12-697250-4.50006-x

Cited by 17 publications

(6 citation statements)

References 350 publications

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“…Recently we found a copper-mediated cyclization of ortho -phenylazo aniline where the adjacent azo-aniline moiety undergoes oxidative cyclization by net removal of 2H + /2e – , which is in good agreement with previous reports that describe mechanistic aspect of the reaction. , The typical reaction conditions, however, require high temperature and elongated time to complete the chemical transformation . On the basis of the mechanistic understanding, we envisioned that implementation of more electron-donating groups (EDG) on the probe would accelerate the reaction, and one N,N -diethylamino group indeed renders the reaction to occur at room temperature.…”

Section: Background: Design Considerationssupporting

confidence: 87%

“…36,37 The typical reaction conditions, however, require high temperature and elongated time to complete the chemical transformation. 38 On the basis of the mechanistic understanding, we envisioned that implementation of more electron-donating groups (EDG) on the probe would accelerate the reaction, 39 and one N,Ndiethylamino group indeed renders the reaction to occur at room temperature. Although the reaction rate was also remarkably shortened to approximately 5−10 min, such a slow reaction limits the capability of high-throughput analysis such as flow injection mode which is normally completed in less than 1 min.…”

Section: ■ Background: Design Considerationsmentioning

confidence: 99%

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Rapid Turn-On Fluorescence Detection of Copper(II): Aromatic Substituent Effects on the Response Rate

Jung

Dinescu

2017

Org. Process Res. Dev.

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Oxidative cyclization of o-phenylazo aniline was utilized as a turn-on fluorescent probe of the copper(II) ion. The number and the position of electron donating groups on the probes were systematically varied to investigate the effect of aryl substituent on reactivity toward copper ion. Among the series of analogous probes, the 2,4,6-trimethoxy substituted probe exhibits not only a faster (40-times faster) reaction but also a lower detection limit (20 times lower) than previously reported probes under identical conditions. The comparative kinetic studies reveal that both the number and the position of substitution have a significant impact on the reactivity toward copper, which will be discussed in the manuscript.

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Section: Background: Design Considerationssupporting

confidence: 87%

Section: ■ Background: Design Considerationsmentioning

confidence: 99%

Rapid Turn-On Fluorescence Detection of Copper(II): Aromatic Substituent Effects on the Response Rate

Jung

Dinescu

2017

Org. Process Res. Dev.

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“…As part of our investigations of mineral effects on hydrothermal organic reactivity, we have discovered some simple organic oxidation reactions that use copper in oxidation state (II). In the context of classical organic chemistry, oxidations generally use heavy, often toxic, or expensive metals, − whereas enzymatic and also geologic redox reactions use more Earth-abundant metals such as iron, nickel, zinc, and copper. − Copper(I) and copper(II) are mild oxidizing agents for organic chemistry; nevertheless, copper salts have previously found use in several organic oxidations . In particular, copper salts are useful catalysts for organic oxidations where oxygen (O 2 ) is the oxidant, ,− including some hydrothermal reactions .…”

Section: Introductionmentioning

confidence: 99%

Organic Oxidations Using Geomimicry

et al. 2015

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Oxidations of phenylacetic acid to benzaldehyde, benzyl alcohol to benzaldehyde, and benzaldehyde to benzoic acid have been observed, in water as the solvent and using only copper(II) chloride as the oxidant. The reactions are performed at 250 °C and 40 bar, conditions that mimic hydrothermal reactions that are geochemically relevant. Speciation calculations show that the oxidizing agent is not freely solvated copper(II) ions, but complexes of copper(II) with chloride and carboxylate anions. Measurements of the reaction stoichiometries and also of substituent effects on reactivity allow plausible mechanisms to be proposed. These oxidation reactions are relevant to green chemistry in that they proceed in high chemical yield in water as the solvent and avoid the use of toxic heavy metal oxidizing reagents.

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“…During our search for a promising model system in which copper(II) functions as an oxidant to convert nonemissive reactant to emissive product, we came across the oxidative cyclization of o -(phenylazo)aniline ( 1 ) to benzotriazole ( 2 ) shown in Scheme . Despite its conceptual appeal of converting a nonemissive azo dye 1 to a highly fluorescent product 2 , this chemistry typically requires an extended reaction time in basic organic solvents at elevated temperatures, − which significantly diminishes its practical utility as a detection method for copper(II) ion under ambient and biologically relevant conditions.…”

Section: Introductionmentioning

confidence: 99%

Reactivity-Based Detection of Copper(II) Ion in Water: Oxidative Cyclization of Azoaromatics as Fluorescence Turn-On Signaling Mechanism

et al. 2012

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An oxidative cyclization reaction transforms nonemissive azoanilines into highly fluorescent benzotriazoles. We have found that introduction of multiple electron-donating amino groups onto a simple o-(phenylazo)aniline platform dramatically accelerates its conversion to the emissive polycyclic product. Notably, this chemistry can be effected by μM-level concentrations of copper(II) ion in water (pH = 6-8) at room temperature to elicit >80-fold enhancement in the green emission at λ(em) = 530 nm. Comparative kinetic and electrochemical studies on a series of structural analogues have established that the accelerated reaction rates correlate directly with a systematic cathodic shift in the oxidation onset potential of the azo precursors. In addition, single-crystal X-ray crystallographic analysis on the most reactive derivative revealed the presence of a five-membered ring intramolecular hydrogen-bonding network. An enhanced contribution of the quinoid-type resonance in such conformation apparently facilitates the mechanistically required proton transfer step, which, in conjunction with electron transfer at lower oxidation potential, contributes to a rapid cyclization reaction triggered by copper(II) ion in water.

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Oxidation by Cupric Ion

Cited by 17 publications

References 350 publications

Rapid Turn-On Fluorescence Detection of Copper(II): Aromatic Substituent Effects on the Response Rate

Rapid Turn-On Fluorescence Detection of Copper(II): Aromatic Substituent Effects on the Response Rate

Organic Oxidations Using Geomimicry

Reactivity-Based Detection of Copper(II) Ion in Water: Oxidative Cyclization of Azoaromatics as Fluorescence Turn-On Signaling Mechanism

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