- Blue-light-induced processes in a series of azobenzene poly(ester imide)s
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We report on a series of photoresponsive azobenzene poly(ester imide)s thermally converted from their precursor poly(ester amic acid)s. Thermal properties as well as ability for efficient photoinduced chromophore orientation and polymer mass transport under linearly polarized blue irradiation were investigated, focusing on the effect of azo chromophore location within polymer chain. The amount of chromophore alignment studied in the experiment on photoinduced birefringence differed by a factor of l.5 between the materials. Despite the fact that the generated birefringence was of the same order of magnitude, very large differences in efficiency of surface relief grating formation were seen. Specific features of photoresponsive behaviour of the polymers were shown to correlate with the presence or the absence of intrachain C[sbnd]H?π interaction between azobenzene hydrogen and aromatic imide structure, which was revealed by density functional theory (DFT) calculations. Advantageous chromophore location next to the imide groups for effective light-driven processes was shown.
- Kozanecka-Szmigiel, Anna,Konieczkowska, Jolanta,Szmigiel, Dariusz,Antonowicz, Jerzy,Ma?ecki, Jan,Schab-Balcerzak, Ewa
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- Protein Modification via Mild Photochemical Isomerization of Triazenes to Release Aryl Diazonium Ions
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This work describes the development of phenyl diazenyl piperidine triazene derivatives that can be activated to release aryl diazonium ions for labeling of proteins using light. These probes show marked bench stability at room temperature and can be photoisomerized via low-intensity UVA irradiation at physiological pH. Upon isomerization, the triazenes are rendered more basic and readily protonate to release reactive aryl diazonium ions. It was discovered that the intensity and duration of the UV light was essential to the observed diazonium ion reactivity in competition with the traditionally observed photolytic radical pathways. The combination of their synthetic efficiency coupled with their overall stability makes triazenes an attractive candidate for use in bioconjugation applications. Bioorthogonal handles on the triazenes are used to demonstrate the ease by which proteins can be modified.
- Davis, Garrett J.,Townsend, Julia A.,Morrow, Madeline G.,Hamie, Mohamed,Shepard, Abigail J.,Hsieh, Chih-Chieh,Marty, Michael T.,Jewett, John C.
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p. 2432 - 2438
(2021/11/18)
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- Azo Derivatives of Pyrocatechol, Resorcinol, and Salicylic Acid as Collectors for Sulfide Ore Flotation
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Heterocyclic and aromatic azo derivatives of pyrocatechol, resorcinol, and salicylic acid have been investigated as collectors for the flotation of sulfide ores. The acid-base properties of the compounds were studied, their solubility in an alkaline solution was determined. It was established that the fixing of reagents on the surface of the ore occurs mainly by the chemical mechanism. Adsorption constants were calculated. It was found that most of the studied reagents exhibit collective properties with respect to sulfide copper—nickel ore. The use of mixtures of azo compounds with potassium butyl xanthogenate leads to an increase in the degree of extraction of nickel and copper, as well as the quality of the concentrates, in comparison with one butyl xanthogenate.
- Baigacheva, E. V.,Gogolishvili, V. O.,Gusev, V. Yu.
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p. 1734 - 1744
(2020/02/25)
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- ENZYMATICALLY-RELEASABLE ARYL DIAZONIUM SPECIES
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Triazabutadiene molecules and methods of use of triazabutadiene molecules, for example methods and compositions for yielding an aryl diazonium species from a triazabutadiene molecule, e.g., a protected aryl diazonium species in the form of a triazabutadiene. In some embodiments, an enzyme catalyzes the reaction yielding the aryl diazonium species from the triazabutadiene molecule. As an example, the methods and compositions herein may be used for delivery of drugs.
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- A Photobasic Functional Group
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Controlling chemical reactivity using light is a longstanding practice within organic chemistry, yet little has been done to modulate the basicity of compounds. Reported herein is a triazabutadiene that is rendered basic upon photoisomerization. The pH of an aqueous solution containing the water-soluble triazabutadiene can be adjusted with 350 nm light. Upon synthesizing a triazabutadiene that is soluble in aprotic organic solvents, we noted a similar light-induced change in basicity. As a proof of concept we took this photobase and used it to catalyze a condensation reaction.
- He, Jie,Kimani, Flora W.,Jewett, John C.
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supporting information
p. 9764 - 9767
(2015/08/24)
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- Optimization of the azobenzene scaffold for reductive cleavage by dithionite; development of an azobenzene cleavable linker for proteomic applications
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In this paper we conducted an extensive reactivity study to determine the key structural features that favour the dithionite-triggered reductive cleavage of the azo-arene group. Our stepwise investigation allowed identification of a highly reactive azo-arene structure 25 bearing a carboxylic acid, at the ortho position of the electron-poor arene and an ortho-Oalkyl-resorcinol as the electron-rich arene. Based on this 2(2′-alkoxy-4′-hydroxyphenylazo) benzoic acid (HAZA) scaffold, the orthogonally protected difunctional azo-arene cleavable linker 26 was designed and synthesized. Selective linker deprotection and derivatization was performed by introducing an alkyne reactive group and a biotin affinity tag. This optimized azo-arene cleavable linker led to a total cleavage in less than 10 s with only 1 mM dithionite. Similar results were obtained in biological media.
- Leriche, Geoffray,Budin, Ghyslain,Brino, Laurent,Wagner, Alain
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supporting information; experimental part
p. 4360 - 4364
(2010/09/20)
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- A Simple Route for the Synthesis of Chlorosubstituted Arylazobenzenes, Arylazonaphtalenes, and Arylazopyrazoles
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The reaction of arylazophenoles and arylazohydroxypyrazoles (or their tautomer hydrazones) 10, 11, and 15 with POCl3 in dimethylformamide yields chlorosubstituted arylazobenzenes or arylazopyrazoles 12, 13 and 16, resp., in moderate to high yields.The substitution of the OH-group by the Cl-moiety is favoured by acceptor substituents in the aryl fragments ortho- and/or para-linked to the azo group.In case that arylazocompounds derived from resorcinol are used the substitution reaction runs in a stepwise manner giving raise to the formation of o-hydroxy-p-chlorosubstit uted azo compounds 18 primarily and then of dichlorosubstituted azo compounds 19.
- Guenther, R.,Jaehne, E.,Hartmann, H.,Schulze, M.
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p. 945 - 954
(2007/10/02)
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