796. Steric effects in di- and tri-arylmethanes. Part I. Electronic absorption spectra of o-methyl derivatives of Michler's hydrol blue and crystal violet; conformational isomers of crystal violet

Barker, C. C.; Bridge, Mary H.; Stamp, A.P.

doi:10.1039/jr9590003957

Cited by 32 publications

(12 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…16 The reasons behind this red shift are difficult to ascribe to any one factor, since although a bathochromic shift should be produced by the extension of the chromophoric system provided by the naphthyl ring, 40 a similar shift has also been shown to result from ortho-and meta-crowding of one of the rings of CV. 6, 24 The presence of a single band is usually considered a good indication of the involvement of all terminal amino groups in the resonance system, although PPP-MO calculations, using the parameters determined for Malachite Green (i.e. both dimethylamino groups are equally involved), predict a slight splitting of the two transitions of 2a with a bathochromic shift of the band associated with the naphthyl-phenyl axis.…”

Section: Discussionmentioning

confidence: 99%

“…This solvent system was chosen to allow comparison with earlier work 1 and because its acidity is sufficient to promote the complete formation of the dye cation while minimising the possibility of forming other species such as dications. 24 The use of acetic acid also has the advantage of giving easy access to a wide range of solutions of different acid strengths as the addition of water promotes the ionisation of the acid. The dyes were found to obey Beer's law in the concentration range 1-2.5 × 10 Ϫ5 , a range in which the maximum absorbance was kept between 0.5 and 0.9.…”

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

The effects of cyclic terminal groups in di- and tri-arylmethane dyes. Part 2.1 Steric and electronic effects in derivatives of Victoria Blue

Guinot¹,

Hepworth²,

Wainwright³

1998

J. Chem. Soc., Perkin Trans. 2

View full text Add to dashboard Cite

The effects of N-alkyl and heterocycloalkyl substituents on the light absorption properties of a range of novel dyes based on the 1-naphthyl analogue of Crystal Violet, Victoria Blue, have been investigated. Interaction between the N-terminal group and the peri-hydrogen atom on the naphthyl residue can result in deconjugation of the former, whereupon the dyes exhibit Malachite Green character. Such steric influences are correlated with 1 H NMR data.

show abstract

Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

The effects of cyclic terminal groups in di- and tri-arylmethane dyes. Part 2.1 Steric and electronic effects in derivatives of Victoria Blue

Guinot¹,

Hepworth²,

Wainwright³

1998

J. Chem. Soc., Perkin Trans. 2

View full text Add to dashboard Cite

show abstract

“…CV + ClO 4 − are not sufficiently soluble in isooctane to permit a direct determination of the absorption coefficient 19 but aggregation among TPMs is a well-established phenomenon in aqueous solution. 2,22 Thus, 10 −3 M solutions of CV + AcO − in water absorb with a maximum at 540 nm, 15 which is a blue-shift from the value 598 nm observed in dilute aqueous solution and an indication of aggregation. Similar observations have been made with the rhodamines.…”

Section: Electronic Absorption Spectra Of (R 2 N) 3 Tota +mentioning

confidence: 96%

2,6,10-Tris(dialkylamino)trioxatriangulenium salts: a new promising fluorophore. Ion-pair formation and aggregation in non-polar solvents

Laursen

Reynisson

Mikkelsen

et al. 2005

Photochem Photobiol Sci

View full text Add to dashboard Cite

The D3h symmetric tris(dialkylamino)trioxatriangulenium ((R2N)3TOTA+) ions are structurally related to classical stains and fluorophores such as triphenylmethane dyes and rhodamines. New derivatives of (R2N)3TOTA+, in which long flexible alkyl chains surround the planar and rigid aromatic core, have been synthesized and isolated as hexafluorophosphate salts. In contrast to short-chain derivatives of triphenylmethane dyes, the new compounds described here are soluble in hydrocarbon solvents. The photophysical properties of these carbenium salts are investigated. Characteristic alterations of the photophysical properties as a function of solvent polarity, concentration and temperature are observed. A model to rationalize the phenomena is presented comprising three states of aggregation, i.e. freely solvated ions, tight ion-pairs, and dimers of ion-pairs. Reduced symmetry in the tight ion-pairs is held responsible for the observed splitting of the long wavelength absorption band. Exciton coupling in the ion-pair dimers leads to reduced oscillator strength of the S0-S1 transition. The model is supported by semi-empirical calculations of the structures and electronic transitions of the free cation and its ion-pair(s).

show abstract

“…considering the influence of various solvents, with the aim of understanding decomposition mechanism. [2][3][4][5][6][7][8][9][10][11][12] They demonstrated that decomposition of these dyes takes place by demethylation and, in the presence of oxygen, by oxidation. Previous studies on CV degradation by irradiation with UV light were made by the authors using UV-Vis spectrophotometry, high-performance liquid chromatography-photo diode array detector (HPLC-PDA) and only occasionally by LC-mass chromatography (MS).…”

Section: Introductionmentioning

confidence: 99%

Application of LC‐MS and LC‐MS‐MS to the analysis of photo‐decomposed crystal violet in the investigation of cultural heritage materials aging

et al. 2012

View full text Add to dashboard Cite

In this work, the accurate liquid chromatography-ultraviolet-visible (LC-UV-Vis), LC-mass spectrometry (MS) and LC-MS-MS analysis of the photo-degradation products of crystal violet (CV) is reported. CV is a light fugitive early synthetic dye which had a widespread diffusion into the market starting from the end of the XIX century and was used among others by V. Van Gogh and P. Gauguin in their writings, drawings or paintings. On-line photodiode array detector enabled simultaneous UV-Vis spectra acquisition. Many degradation compounds were identified through their exact mass (2 ppm accuracy) and MS-MS technique. In particular, all CV demethylated products, demethylated Michler's ketone and particularly some compounds that most likely contain oxygen, such as N-oxides, were found. Fragmentation products are all justified by the proposed fragmentation scheme, in term of precursor exact mass and isotopic profile, characteristic losses in fragmentation and rebuilt structure formula. In particular, we hypothesized the presence of N-imido oxides and hydroxylamine derivates, never reported before, together with the demethylated derivatives of the studied dyes. All these compounds, although at trace level in our samples, contribute to the discoloration and fading of works of arts made with CV. In particular, demethylation of CV by UV light leads to formation of compounds absorbing at shorter wavelengths than CV (blue shift) or no-absorbing in visible range (yellow-colourless) with an overall effect that may appear reddish-brown. This phenomenon justifies drawings appearing grey or brown on aged yellowed paper, when CV-based inks or paints were used. The final aim was to better characterize the photo-degradation of early synthetic dyes (in particular of CV) and to gain a better insight into the discoloration and fading of purple ink strokes made of CV.

show abstract

796. Steric effects in di- and tri-arylmethanes. Part I. Electronic absorption spectra of o-methyl derivatives of Michler's hydrol blue and crystal violet; conformational isomers of crystal violet

Cited by 32 publications

References 0 publications

The effects of cyclic terminal groups in di- and tri-arylmethane dyes. Part 2.1 Steric and electronic effects in derivatives of Victoria Blue

The effects of cyclic terminal groups in di- and tri-arylmethane dyes. Part 2.1 Steric and electronic effects in derivatives of Victoria Blue

2,6,10-Tris(dialkylamino)trioxatriangulenium salts: a new promising fluorophore. Ion-pair formation and aggregation in non-polar solvents

Application of LC‐MS and LC‐MS‐MS to the analysis of photo‐decomposed crystal violet in the investigation of cultural heritage materials aging

Contact Info

Product

Resources

About