The Relation between the Absorption Spectra and the Chemical Constitution of Dyes. XXVIII. The Hydration of Azo Dyes in Organic Solvents

Brode, Wallace R.; Seldin, Ira L.; Spoerri, Paul E.; Wyman, George M.

doi:10.1021/ja01615a028

Cited by 60 publications

(31 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The observed change confirms the presence of two bands, which are affected diffe~ectially by changing temperature. Further evideace for the presence of two bands comes from the fact that a clearly discernible shoulder IS seen on the low-frequency s~d e of the curve of 4 in 10% ethanol (15) The p r~n c~p a l long-wavelength absorpt~on band of 5 and 6 and of the unsubstituted and y-chloro-subst~tuted analogs are different from those of 1-4, and appear to be s~ngle bands They are nearly symmetric about the maxlmuni on a wavelength plot and are narrower (69 nm at half-peak height for 4 in water compared to 114 nm for MO) Furthermore. transfer of 6 from water to ethanol does not give the blue shift seen w:th 1-4, but a very small red shift (3 nm) The presence of two overlapping bands is character~st~c only of the p-amino der~\atl\:es in the visual region is a single n -t x* transition (28).…”

Section: Resultsmentioning

confidence: 99%

“…The interaction is usually accompanied by spectral changes that are not associated with the acid-base indicator properties of the dye. Binding to bovine serum albumin (BSA) (2, 3), to human serum albumin (HSA) at slightly acid p H values (31, and to surfactant micelles (13,14) gives a shift of the absorption maximum to higher frequencies that can be duplicated by adding ethanol to aqueous solutions of MO (6,15,16). Bind~ng to HSA in mildly alkaline solutions is anomaious in that the absorption curve is shifted to lower frequencies and increases in intensity (3,7).…”

mentioning

confidence: 99%

“…Forbes and Milligan (6) showed that an earlier proposal involving electrostatic interactions between protonated amino groups sf the protein with the sulfonate group of 1 2 / 2 0 (2) was incorrect. The in~portance of the p-dimethylamino group in giving the spectrai changes was recognized (3,6,15) For personal use only. been proposed (6,15).…”

mentioning

confidence: 99%

“…The in~portance of the p-dimethylamino group in giving the spectrai changes was recognized (3,6,15) For personal use only. been proposed (6,15). Forbes and Milligan predicted correctly that hydrogen-bonding to the azo nitrogens should give a red shift (17)(18)(19), and out-of-plane twisting should give a blue shift, but were incorrect in their suggestion that hydrogen-bonding to the amino group should also give a red shift (19).…”

mentioning

confidence: 99%

“…Forbes and Milligan predicted correctly that hydrogen-bonding to the azo nitrogens should give a red shift (17)(18)(19), and out-of-plane twisting should give a blue shift, but were incorrect in their suggestion that hydrogen-bonding to the amino group should also give a red shift (19). Brode and co-workers alone have recognized that the absorption curve of MO could consist of two overlapping bands and interpreted the low-frequency component as arising from a solvate containing a hydrogen bond between water and the azo group (15).…”

mentioning

confidence: 99%

See 4 more Smart Citations

Analysis of the Visual Spectrum of Methyl Orange in Solvents and in Hydrophobic Binding Sites

Reeves¹,

Kaiser²,

Maggio³

et al. 1973

Can. J. Chem.

View full text Add to dashboard Cite

The absorption curves of methyl orange (MO) and analogous p-aminophenylazobenzenes in organic and aqueous organic solvents are shown to consist of two severely overlapping bands. The curves have been resolved into two skewed component bands using a regression method. The blue shift of the absorption maximum obtained when organic solvents are added to aqueous solutions of MO, or when MO is bound to bovine serum albumin or a surfactant micelle, is the result of a change in relative intensities of the component bands. The low-frequency component is assigned to a n, -. nlx transition of a solvate in which there is specific hydrogen-bonding interaction between solvent and the azo nitrogens, and the high-frequency component to a n1 + nl* transition of a solvate in which the interaction is absent. The low-frequency component is favored by aqueous solvent compositions and by low temperatures. The free energies of interconversion of the species in various hydrogen-bonding solvents are correlated by the solvent surface tension but not by the dielectric constant. The results show that the shift in absorption maximum accompanying binding to a protein or micelle should be interpreted as a shift in an equilibrium rather than as a shift in transition energy.Les courbes d'absorption du methylorange (MO) et des p-aminophCnylazobenzenes analogues, en solvants organiques et organiques aqueux, comprennent deux bandes fortement enchevktrees. La resolution de ces courbes en deux bandes gauches elementaires a ete faite par la methode de regression. Le d6placement vers le bleu du nlaxilnuin d'absorption, obtenu par addition de solvants organiques aux solutions aqueuses de MO ou lorsque le MO est lie a l'albumine du serum bovin ou a une micelle surfactive, est le resultat du changement des intensites relatives des bandes composantes. La bande a basse frequence est attribue a la transition n, + nl*, d'un produit de solvatation dans lequel il y a interaction specifique par liaison hydrogene entre le solvant et les azotes de l'azo; la bande a haute frequence correspond a la transition nl + n," du produit de solvatation sans interaction. La bande a basse frequence est favorisee par la composition en eau des solvants et aux basses temperatures. Les energies libres de l'interconversion des diverses especes dans differents solvants a liaison hydrogene, ont ete reliies a la tension superficielle du solvant et non a la constante dielectrique. Les rtsultats montrent que le deplacement du maximum d'absorption consecutif a une liaison a une protkine ou ~nicelle devraient &tre interpretes pluttit comme un deplacement d'equilibre qu'un diplacement de 1'Cnergie de transition.[Traduit par le journal]Can. J. Chem.. 51. 628 (1973) Methyl orange (MO, 1) has been used as a probe for studying the interaction of organic anions with proteins (1-9), synthetic polymers (10, 1 I), polyelectrolytes (12), and surfactants (12-14) in aqueous solution. The interaction is usually accompanied by spectral changes that are not associated with the acid-base indicator p...

show abstract

Section: Resultsmentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

See 3 more Smart Citations

Analysis of the Visual Spectrum of Methyl Orange in Solvents and in Hydrophobic Binding Sites

Reeves¹,

Kaiser²,

Maggio³

et al. 1973

Can. J. Chem.

View full text Add to dashboard Cite

show abstract

Synthesis and chiroptical properties of optically active photochromic polymers with side-chainL-lactic residues connected totrans-azobenzene moieties bearing a reactive formyl electron-withdrawing group

Angiolini¹,

Caretti

Carlini

et al. 1999

Macromol. Chem. Phys.

View full text Add to dashboard Cite

SUMMARY: The synthesis of a novel optically active monomer containing a photochromic chromophore, trans-(S)-4-(2-methacryloyloxypropanoyloxy)-49-formylazobenzene, is described. The monomer was radically homopolymerized and copolymerized with methyl methacrylate to afford the corresponding optically active polymers, which were fully characterized. The chirooptical and conformational properties in solution of the resulting polymers were investigated by circular dichroism and solvatochromism measurements and compared with those of the corresponding low molecular weight model compound, trans-(S)-4-(2-pivaloyloxypropanoyloxy)-49-formylazobenzene, purposely synthesized.

show abstract

Synthesis and chiroptical properties of optically active methacrylic polymers bearing the (S)- and/or (R)-2-hydroxysuccinimide moiety linked to thetrans-azobenzene group in the side chain

Angiolini¹,

Caretti

Giorgini

et al. 2000

Macromol. Chem. Phys.

View full text Add to dashboard Cite

The Relation between the Absorption Spectra and the Chemical Constitution of Dyes. XXVIII. The Hydration of Azo Dyes in Organic Solvents

Cited by 60 publications

References 0 publications

Analysis of the Visual Spectrum of Methyl Orange in Solvents and in Hydrophobic Binding Sites

Analysis of the Visual Spectrum of Methyl Orange in Solvents and in Hydrophobic Binding Sites

Synthesis and chiroptical properties of optically active photochromic polymers with side-chainL-lactic residues connected totrans-azobenzene moieties bearing a reactive formyl electron-withdrawing group

Synthesis and chiroptical properties of optically active methacrylic polymers bearing the (S)- and/or (R)-2-hydroxysuccinimide moiety linked to thetrans-azobenzene group in the side chain

Contact Info

Product

Resources

About