Azobenzene-sulfonate

Tropeolin OO, orange IV, sodium p-diphenylamino-azobenzene sulfonate, sodium 4 -anilino-azobenzene-4-sulfonate (indicator) dissolve 0.1 g in 100 mL water pH range red 1.3-3.2 yellow. 

Di azobenzene Sulfonic Acid. See Benzenediazonium Sulfonic Acid in Vol 2 , p B57-L... 

Analogous membranes have been prepared from poly(L-glutamic acid) containing about 14 mol % azobenzene-sulfonate groups in the side chains (Scheme 3, Structure IV). 25 109 The polypeptide was adsorbed onto a porous support and the hydro-... 

A satisfactory isolation procedure has been described recently by Stdn et al. (755). After refiuxing silk fibroin for 8 hours with concentrated hydrochloric acid, the bulk of the acid is removed by vacuum distillation and treatment with lead acetate. Tyrosine is removed, the concentrated filtrate is treated with a solution of 5-nitronaphthalene-l-sulfonic acid dihydrate and the slightly soluble glycine naphthalene sulfonate is removed. Methyl cellosolve and a solution of azobenzene-p-sulfonic acid trihydrate are added, the suspension is filtered and the precipitate of L-alanine azobenzene sulfonate is treated with barium acetate. The suspension of barium azobenzene sulfonate is filtered and the L-alanine obtained from the filtrate is recrystallized from aqueous ethanol see p. 359. 

No reaction occurs under these conditions with esters, acid chlorides, acid anhydrides, azobenzene, sulfones, and sulfonyl chlorides. The following groups evolve hydrogen but do not undergo reduction alcohols, phenols, carboxylic acids, amides, and sulfonic acids. Aldehydes and ketones are reduced to alcohols, and N,N-dimethylamides to aldehydes. F. e. s. H. C. Brown and D. B. Big-ley, Am. Soc. 83, 486 (1961). 

Once substituents are introduced on even one aromatic ring, these two systems deviate. Thus structure (III) becomes azobenzene-4-sulfonic acid in... 

The most important feature of the spectra is the large blue shift of the sulfones vs the nitro derivatives, i.e., 53 nm (3098 cm 1) for the stilbene, and 30 nm (1400 cm 1) for the azobenzene derivatives, in toluene). These large blue shifts suggest that sulfonyl compounds are more transparent in the visible region than their nitro... 

Poly(L-lysine) containing azobenzene units linked to the side chains by means of a sulfonamide function (Scheme 4, Structure VI), was obtained by treating poly(L-lysine) with p-phenylazobenzenesulfonyl chloride. The poly(a-amino acid) was modified quantitatively conversion to the azo-lysine units of VI was effectively 100%. The azo-modified polypeptide was soluble in HFP, in which it exhibited an intense photochromism attributed to the trans-cis photoisomerization of the azobenzene units. Like other sulfonated azobenzene compounds, 33 azosulfonyl-modified polymers of L-lysine were found to be very stable in their tis form, and no thermal decay was observed at room temperature over periods of times as long as several weeks. Interconversion between the two forms at room temperature could only be effected by irradiation at appropriate wavelengths. This behavior allowed the authors to purify the trans and cis forms of the model compound NE-azobenzenesulfonyl-L-lysine (VII) by chromatography, and to measure the absorption spectra of the two pure photoisomers. 

Chippendale et al.m studied 13C and 15N CP/MAS NMR of free acids and sodium salts of a series of sulfonated azobenzene dyestuffs (39). In solution the spectra of both free acid and salts are characteristic of /rani-azobenzene structures, as are the spectra of the solid samples of the salts. The spectra of the solid free acids are markedly different from those of the corresponding solid sodium salts (Tables 17 and 18) and exist as azonium tautomers (three resonance structures are shown for 39f). Solid-state structures of this type are probably stabilized by the formation of intermolecular bonds. 

The peak shift due to aggregation is observed not only in LBK films containing azobenzene chromophores, but also for other chromophores with extended Ji-systems, such as viologen polymers. For monolayers of the poly(p-phenylene sulfonate) 9/ dioctadecyldimethylammonium bromide (DODA) complex, the peak shift due to aggregation results in a piezo-chromic effect—that is, upon compression of the monolayer, a significant shift of the poly(p-phenylene sulfate) A band is observed (see Figure 6.9). This photochromic effect has been shown to be based on the improved 7t-Jt interaction upon compression of the monolayer. ... 

Xu, Z. S., Drnoyan, V., and Natansohn, A., and Rochon, P. Novel polyesters with amtno-sulfone azobenzene chromophores in the main chain. J Polym Sci Pol Ghent, 2000, 38, pp. 2245-2253. 

Photocontrol of the transport property was also studied for poly(L-glutamic acid) membrane with azobenzene-4-sulfonic acid residues [61]. 

In fact, the photochemical process Is much less sensitive to the rigidity of the system if the azobenzene Is attached as a side chain. Copolymer ABA-MMA exhibited a quantum efficiency only 4-5 times lower In a glassy film then in dilute solution ( ). By contrast. Figure 3 shows the relative quantum efficiencies for the trans-cls Isomerization of a copolyamlde of Isophthallc acid with 4,4 -dlamlnodlphenyl sulfone containing a small proportion of... 

According to a preliminary report, diimide can be generated at 0° by the action of sodium hydroxide on chloroacetylhydrazide hydrochloride (which see). Another precursor is hydroxylamine-O-sulfonic acid (which see). Azobenzene has been reduced quantitatively to hydrazobenzene and tdlyl alcohol to propanol (70%). ClCHjCONHNHi HCl + 2 NaOH ----------> CH2=C=0 + HjO + HN=NH + 2 NaCff... 

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