Nitric Oxide Catalysis of Diazene <i>E</i>/<i>Z</i> Isomerization

Bohle, D. Scott; Rosadiuk, Kristopher A.

doi:10.1021/acs.inorgchem.5b00476

Cited by 7 publications

(6 citation statements)

References 51 publications

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“…Surprisingly, enhancements can be detected for all nitrogen positions including the amino group, presumably due to the existence of the enamine–imine tautomer, which is structurally similar to Schiff bases (or indirect polarization transfer). Diphenyldiazene (entry 11) exhibits E / Z isomerism induced optically, , or chemically . Interestingly the Z form is hyperpolarized exclusively despite the fact that the E form is thermodynamically stable.…”

Section: Results and Discussionmentioning

confidence: 99%

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Generalizing, Extending, and Maximizing Nitrogen-15 Hyperpolarization Induced by Parahydrogen in Reversible Exchange

et al. 2017

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Signal Amplification by Reversible Exchange (SABRE) is a fast and convenient NMR hyperpolarization method that uses cheap and readily available para-hydrogen as a hyperpolarization source. SABRE can hyperpolarize protons and heteronuclei. Here we focus on the heteronuclear variant introduced as SABRE-SHEATH (SABRE in SHield Enables Alignment Transfer to Heteronuclei) and nitrogen-15 targets in particular. We show that 15N-SABRE works more efficiently and on a wider range of substrates than 1H-SABRE, greatly generalizing the SABRE approach. In addition, we show that nitrogen-15 offers significantly extended T1 times of up to 12 minutes. Long T1 times enable higher hyperpolarization levels but also hold the promise of hyperpolarized molecular imaging for several tens of minutes. Detailed characterization and optimization are presented, leading to nitrogen-15 polarization levels in excess of 10% on several compounds.

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Section: Results and Discussionmentioning

confidence: 99%

“…Diphenyldiazene (entry 11) exhibits E/Z isomerism induced optically, 49,50 or chemically. 51 Interestingly the Z form is hyperpolarized exclusively despite the fact that the E form is thermodynamically stable. Enhancements of the Z-form, in presently unknown low concentration, significantly exceed 40fold (see SI).…”

Section: ■ Methodsmentioning

confidence: 99%

Generalizing, Extending, and Maximizing Nitrogen-15 Hyperpolarization Induced by Parahydrogen in Reversible Exchange

et al. 2017

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“…Azo compounds are usually synthesized through a diazotization coupling reaction, with asymmetric structures − (as shown in Scheme a). However, the novel colorants developed in this study are biscatecholic azobenzene compounds with a symmetric structure, and their precursors, the azo chromophores, are suitable to be synthesized via an oxidization–coupling reaction, − where aromatic amines can self-couple to form azo bonds (as shown in Scheme b). Based on the symmetric structure, two dopamine molecules could be simply incorporated into the azo chromophore through a one-step reaction.…”

Section: Results and Discussionmentioning

confidence: 99%

Novel and Sustainable Colorants Developed via Incorporating Azo Chromophores into Dopamine Molecules

Fan

Lam

et al. 2022

ACS Omega

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Inspired by the application of dopamine as an “anchor” and UV absorber, novel sustainable colorants with biscatecholic structure were synthesized through a simple incorporation of simple azo chromophores with dopamine. Their structures were confirmed using MS and NMR analyses, and their application on textile materials was investigated. Compared to the simple azo chromophores with almost no coloring ability on fabrics, the biscatecholic colorants could color different fabrics effectively, mainly through self-polymerization only in the presence of a trace amount of organic base at room temperature, which is environmentally friendly in terms of saving resources and alleviating chemical pollution. Meanwhile, the UV resistance of colored fabrics was enhanced significantly, showing the advantage of protecting wearers from UV damage.

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“…47 In prior publications, we have found that B3LYP/6-311++G** is an excellent combination of method and model for the ground-state geometries and vibrational modes or electronrich nitrogen species with multiple lone pairs such as these. 48,49 Here, the inclusion of diffuse functions is an important factor. 50,51 This is the case for these urea starting materials and hydrazine products, which have theoretically calculated ground-state structures and vibrational modes (supplementary information S28-S31) that match well the expected intensities and positions of the experimental data.…”

Section: Resultsmentioning

confidence: 99%

Synthesis of reduction-sensitive 1,1-diarylhydrazines from 1,1-diarylamines

et al. 2014

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1-(2-Nitrophenyl)-1-phenylamine and methyl 4-((2-nitrophenyl)amino)benzoate have been transformed into their corresponding urea derivatives through the action of chlorosulfonyl isocyanate. The initial sulfimidate product from the former reaction has sufficient stability so that it can be isolated and characterized as its disodium salt, and this, as well as three other subsequent products, have been characterized by X-ray diffraction. The corresponding intermediary urea was converted into its hydrazine derivative via a Hofmann rearrangement under oxidative conditions. Density functional theory has been used to examine the nature of the intermediates and transition states for the Hofmann rearrangement. There is little theoretical indication for a cyclic aziridinonium intermediate and the transition state between the urea and the isocyanate corresponds to a reactant-like rotation of the planar singlet nitrene before migration and formation of the new N−N bond.Résumé : La 1-(2-nitrophényle)-1-phénylamine et la 4-((2-nitrophényle)amino)benzoate de méthyle ont été transformé par leur réaction avec l'isocyanate de chlorosulfonyle en leurs urées correspondantes. Dans le premier cas, le produit initial de cette réaction, un sulfimidé, démontre une stabilité qui permet son isolement comme sel de sodium. Celui-ci ainsi que trois produits ultérieurs ont été caractérisés par diffraction de rayons X. L'urée de 1-(2-nitrophényle)-1-phénylamine a été transformé en hydrazine par réarrangement de Hofmann sous conditions oxydatives. La théorie de la fonctionnelle de la densité a été utilisé afin d'examiner les intermédiaires et les états de transition de ce réarrangement. Les calculs indiquent qu'un intermédiaire aziridononium cyclique est peu probable et que l'état de transition qui mène de l'urée à l'isocyanate et finalement à l'hydrazine correspond à une rotation de la nitrène planaire de forme singulet avant sa migration et la formation d'une nouvelle liaison entre les deux atomes d'azote.

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Nitric Oxide Catalysis of Diazene E/Z Isomerization

Cited by 7 publications

References 51 publications

Generalizing, Extending, and Maximizing Nitrogen-15 Hyperpolarization Induced by Parahydrogen in Reversible Exchange

Generalizing, Extending, and Maximizing Nitrogen-15 Hyperpolarization Induced by Parahydrogen in Reversible Exchange

Novel and Sustainable Colorants Developed via Incorporating Azo Chromophores into Dopamine Molecules

Synthesis of reduction-sensitive 1,1-diarylhydrazines from 1,1-diarylamines

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