Spectres Raman de Résonance de Dérivés Substitués de l'Aminoazobenzéne en Solution Acide

Merlin, J.; Lorriaux, J. L.; Dupaix, Alain; Thomas, Emrys W.

doi:10.1002/jrs.1250110215

Cited by 13 publications

(4 citation statements)

References 26 publications

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“…A similar coupling perturbed by deuterium exchange of a N-H group in an analogous system has been previously observed (6).…”

Section: Deprotonated Formssupporting

confidence: 80%

“…(iv) The N-N stretching mode has been previously observed at 1202 cm-' for diazoaminobenzene (1 1) and in the 1160-1200 cm-' spectral range for other azobenzene derivatives in acid solution where hydrazone forms appear (6,14,15), so it is expected between 1150 and 1210 cm-'. However, a and p I5N labelling unambiguously assigns the 1363 cm-' line in the PHPD spectrum as the N-N stretching; its relatively high frequency in this case would indicate a correspondingly high N-N bond order.…”

Section: Deprotonated Formsmentioning

confidence: 78%

“…Line frequencies were quoted to an accuracy of 2 2 cm-' by using plasma lines for calibration. Techniques and precautions used in the acquisition of resonance Raman spectra were fully described in previous publications (5,6). The pK, determination for (2-carboxy)-PHPD involved plotting the ratio of the intensities of the 1368 cm-' and 1250 cm-' lines (characteristic of the acid and basic forms of the molecule) against pH.…”

Section: Spectral Measirrementsmentioning

confidence: 99%

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Resonance Raman study of phenylhydrazonopropanedinitriles

Merlin¹,

Thomas²,

Petit³

1985

Can. J. Chem.

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Resonance Raman spectra and band assignments of some phenylhydrazonopropanedinitriles, including the 3-chloro and the 2-carboxy derivatives, in the 900–2300 cm−1 spectral range are presented and discussed. I5N and 2H isotopic shifts have been used to clarify the assignments, which have been made for both protonated and deprotonated forms of the compounds. The resonance Raman spectra of the protonated forms show strong coupling between NH deformation and hydrazone vibrations. This coupling is lost in the anionic forms, which are considered to have considerable carbanion character. By using the drastic changes between the resonance Raman spectra of protonated and deprotonated forms, the pKa value of the 2-carboxy derivative has been determined.

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“…A similar coupling perturbed by deuterium exchange of a N-H group in an analogous system has been previously observed (6).…”

Section: Deprotonated Formssupporting

confidence: 80%

Section: Deprotonated Formsmentioning

confidence: 78%

Section: Spectral Measirrementsmentioning

confidence: 99%

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Resonance Raman study of phenylhydrazonopropanedinitriles

Merlin¹,

Thomas²,

Petit³

1985

Can. J. Chem.

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“…4 and 5. A more complete analysis would include quinoid forms (17,18) but, for our purposes, a simplified scheme is sufficient. The ortho position of the COO-group in MR as opposed to the para position of the SO3-substituent in MO affords stability to azo nitrogen protonation through the formation of a sixmembered ring for MR.…”

Section: Discussionmentioning

confidence: 99%

Kinetics of the interactions between dyes and micelles

Reinsborough¹,

Holzwarth²

1986

Can. J. Chem.

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. J. Chem. 64, 955 (1986).The rates of association of three azo dyes, methyl red (MR), methyl orange (MO), and pyridine-2-azo-p-dimethylaniline (PADA), with sodium dodecylsulfate (SDS) and cetyltrimethylammonium bromide (CTAB) micelles in water were measured at 25°C over a wide pH range by the continuous flow method of integrating observation (CFMIO). The association was considered in 3 steps: bulk solution encounter, pH jump, and electrostatic and hydrophobic interactions. Either the first or third step is rate limiting depending on the charge of the dye. The rate constant of association of neutral PADA, MR, and MO with SDS micelles is approximately 2 X 10' dm3 mol-' s-' while charging the dyes positively increases k to lo9 dm3 mol-' s-'. Increasing the hydrophobicity of dye or micelle increases k for the interaction with the neutral dye species. Changes in k with pH for the dye-CTAB association were less pronounced.

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