Reactions of the OH adducts of cytosine and its derivatives with TEMPO and TEMPOL: A steady state γ-radiolysis and pulse radiolysis study

Chabita, K.; Mandal, P. C.; Mahal, H. S.; Mukherjee, Tulsi

doi:10.1163/156856701317051680

Cited by 4 publications

(2 citation statements)

References 23 publications

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“…Chabita and Mandal investigated a variety of TEMPO-like molecules and found the redox potential for these molecules to be between 0.85 and 1.0 V vs NHE ͑3.85 to 4.0 V vs Li/Li + ͒. 26 The diffusion coefficients were of the order 10 −5 cm 2 s −1 in aqueous solution. Both of these values are near those of the molecule 2,5-di-tert-butyl-1,4-dimethoxybenzene.…”

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confidence: 99%

The Use of 2,2,6,6-Tetramethylpiperinyl-Oxides and Derivatives for Redox Shuttle Additives in Li-Ion Cells

Buhrmester¹,

Moshurchak

Wang³

et al. 2006

J. Electrochem. Soc.

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The stable radical, 2,2,6,6-tetramethylpiperinyl-oxide ͑TEMPO͒, is shown to be a stable redox shuttle in Li 4/3 Ti 5/3 O 4 /LiFePO 4 Li-ion coin cells providing over 120 cycles of shuttle-protected overcharge. Derivatives of TEMPO, such as 4-methoxy-TEMPO and 4-cyano-TEMPO are also stable. Relatives of TEMPO, having a five-membered ring, such as 3-cyano-2,2,5,5-tetramethyl-1-pyrrolidinyloxy ͑3-cyano-PROXYL͒ show similar stability. One disadvantage of these molecules is their relatively low oxidation potentials, which are too close to that of LiFePO 4 for commercial applications. Ab initio calculations show that the redox potential of these molecules can be tailored by substitutions of fluorine for the hydrogen atoms in the methyl groups.A stable radical molecule is 2,2,6,6-tetramethylpiperidinyl-oxide, which is widely known as TEMPO. The unusual feature of this molecule is its stability as a neutral radical. Figure 1 shows that the nitroxide, which carries the radical, is sterically protected. The dimerization factor of TEMPO, which is the fraction of molecules that exist as dimers, is thus very low and was measured by Grampp et al. in 2001 to be 2.5 ϫ 10 −4 at 298 K in solution. 1 Evidence for the usefulness of TEMPO in a variety of applications comes from over 3100 publications since 1961, of which around 600 are patents. The first major article about TEMPO might be that by Weil et al. in 1968. 2 Their article in Nature shows TEMPO to be a stable nitroxide as a lipid antioxidant. From then on the investigation of TEMPO increased significantly. More than 200 publications can be found using TEMPO as an antioxidant and especially in the last 10 years as protection against oxidative cellular damage. Another, larger field is the use of TEMPO for organic catalytic reactions and in the application of polymer synthesis. 3-6 Only five references from over 600 articles on the topic are given. Studies of TEMPO can be found in journals spanning different scientific fields, including those focusing on medicinal and biological research.Since the year 2000, TEMPO and its derivatives have also been used in secondary batteries, mainly to enhance cycling performance, as a fire retardant, or as an additive in lithium-sulfur batteries. 7-12 In the past years, functional groups found in TEMPO have been incorporated into a polymer that was then successfully used as the positive electrode in an organic radical battery. [13][14][15][16][17][18][19][20] In another investigation, molecules with a TEMPO "core" were used as a liquid electrode. 21 Our work has shown that TEMPO and some close derivatives of TEMPO can potentially be used as redox shuttles in lithium-ion batteries. These TEMPO molecules are among the best shuttle molecules known to us, in terms of length of overcharge protection offered.The search for stable shuttle molecules with appropriate oxidation potential has been very difficult. Out of a search of more than 60 aromatic molecules, only one molecule, namely 2,5-di-tert-butyl-1,4-dimethoxybenzene, proved to be successfu...

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The Use of 2,2,6,6-Tetramethylpiperinyl-Oxides and Derivatives for Redox Shuttle Additives in Li-Ion Cells

Buhrmester¹,

Moshurchak

Wang³

et al. 2006

J. Electrochem. Soc.

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“…Of particular synthetic interest is the oxidation of alcohols to carbonyl compounds [21,22]. Industry generally employs nitroxyl derivatives functionalized in the 4 position, such as 4-hydroxy-TEMPO obtained from the cheap precursor triacetoneamine, a readily available chemical manufactured in large amounts as a light stabilizer for plastics.…”

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confidence: 99%

Improved synthesis of 2-norbornanone

Zhang

Tao

et al. 2015

Res Chem Intermed

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Herein a two-step process for the synthesis of 2-norbornanone with 91 % overall yield has been developed. The addition of sublimation inhibitors suppressed the sublimation of norbornene in the process of sulfuric acid-promoted hydration and increased the yield of 2-norbornanol significantly under mild conditions. Additionally, reuse of sulfuric acid has been achieved. A 4-hydroxy-TEMPO/CuCl/TBN triplecomponent catalyst system for the highly selective aerobic oxidation of 2-norbornanol was developed and displayed high atom efficiency and yield.

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Poly(alizarin red)/Graphene modified glassy carbon electrode for simultaneous determination of purine and pyrimidine

Luo

Ding

et al. 2012

Analytica Chimica Acta

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Reactions of the OH adducts of cytosine and its derivatives with TEMPO and TEMPOL: A steady state γ-radiolysis and pulse radiolysis study

Cited by 4 publications

References 23 publications

The Use of 2,2,6,6-Tetramethylpiperinyl-Oxides and Derivatives for Redox Shuttle Additives in Li-Ion Cells

The Use of 2,2,6,6-Tetramethylpiperinyl-Oxides and Derivatives for Redox Shuttle Additives in Li-Ion Cells

Improved synthesis of 2-norbornanone

Poly(alizarin red)/Graphene modified glassy carbon electrode for simultaneous determination of purine and pyrimidine

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