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Solvent effect on the spectral properties of Neutral Red.

Rauf MA, Soliman AA, Khattab M - Chem Cent J (2008)

Bottom Line: This showed that the unified scale for estimating the solvent effect on the absorption of the Neutral Red dye is more adopted and more applicable than the pi* scale model.The unified scale for estimating the solvent effect on the absorption of Neutral Red dye is more adopted and more applicable than the pi* scale model.This may be due to complications from both pi-pi* charge transfer interactions and incomplete complexation of the solute; these effects are averaged out in the derived beta and pi parameters and thus limit their applicability.

View Article: PubMed Central - HTML - PubMed

Affiliation: Chemistry Department, UAE University, Al-Ain, UAE. raufmapk@yahoo.com

ABSTRACT

Background: The study was aimed at investigating the effect of various solvents on the absorption spectra of Neutral Red, a dye belonging to the quinone-imine class of dyes. The solvents chosen for the study were water, ethanol, acetonitrile, acetone, propan-1-ol, chloroform, nitrobenzene, ethyleneglycol, acetic acid, DMSO and DMF.

Results: The results have shown that the absorption maxima of dyes are dependent on solvent polarity. In non-hydrogen-bond donating solvents, solvation of dye molecules probably occurs via dipole-dipole interactions, whereas in hydrogen-bond donating solvents the phenomenon is more hydrogen bonding in nature. To estimate the contribution of the different variables on the wave number of the Neutral Red dye, regression analyses using the ECW model were compared with the pi* scale model. This showed that the unified scale for estimating the solvent effect on the absorption of the Neutral Red dye is more adopted and more applicable than the pi* scale model.

Conclusion: Absorption maxima of dyes are dependent on solvent polarity. Solvation of dye molecules probably occurs via dipole-dipole interactions in non-hydrogen-bond donating solvents, whereas in hydrogen-bond donating solvents the phenomenon is more hydrogen bonding in nature. The unified scale for estimating the solvent effect on the absorption of Neutral Red dye is more adopted and more applicable than the pi* scale model. This may be due to complications from both pi-pi* charge transfer interactions and incomplete complexation of the solute; these effects are averaged out in the derived beta and pi parameters and thus limit their applicability.

No MeSH data available.


Related in: MedlinePlus

Chemical Structure of Neutral Red.
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Figure 1: Chemical Structure of Neutral Red.

Mentions: The present study deals with the solvent effect on the absorption spectra of Neutral Red (NR), which belongs to Quinone-Imine class of dyes. The molecular structure of this dye is shown in figure 1. Absorption spectrum of the dye solution was recorded in different solvents with the aim to probe the effects of various solvents and correlate various absorption parameters to dye spectra in various solvents. For this purpose solvents of different types were selected, firstly the non hydrogen-bond donating solvents (also called as non-HBD type of solvents) such as acetone, acetonitrile, nitrobenzene, DMF and DMSO; and secondly the hydrogen-bond donating solvents (also called as HBD type solvents) such as water, ethanol, acetic acid, ethyleneglycol, chloroform and propan-1-ol. The values of λmax of Neutral Red in these solvents are given in Table 1. One can see from this table that the absorption maximum of the dye is affected by solvent type and has a maximum shift of Δλ = 22 nm for the solvents used in this work. Thus this change in spectral position can be used as a probe for various types of interactions between the solute and the solvent.


Solvent effect on the spectral properties of Neutral Red.

Rauf MA, Soliman AA, Khattab M - Chem Cent J (2008)

Chemical Structure of Neutral Red.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2571090&req=5

Figure 1: Chemical Structure of Neutral Red.
Mentions: The present study deals with the solvent effect on the absorption spectra of Neutral Red (NR), which belongs to Quinone-Imine class of dyes. The molecular structure of this dye is shown in figure 1. Absorption spectrum of the dye solution was recorded in different solvents with the aim to probe the effects of various solvents and correlate various absorption parameters to dye spectra in various solvents. For this purpose solvents of different types were selected, firstly the non hydrogen-bond donating solvents (also called as non-HBD type of solvents) such as acetone, acetonitrile, nitrobenzene, DMF and DMSO; and secondly the hydrogen-bond donating solvents (also called as HBD type solvents) such as water, ethanol, acetic acid, ethyleneglycol, chloroform and propan-1-ol. The values of λmax of Neutral Red in these solvents are given in Table 1. One can see from this table that the absorption maximum of the dye is affected by solvent type and has a maximum shift of Δλ = 22 nm for the solvents used in this work. Thus this change in spectral position can be used as a probe for various types of interactions between the solute and the solvent.

Bottom Line: This showed that the unified scale for estimating the solvent effect on the absorption of the Neutral Red dye is more adopted and more applicable than the pi* scale model.The unified scale for estimating the solvent effect on the absorption of Neutral Red dye is more adopted and more applicable than the pi* scale model.This may be due to complications from both pi-pi* charge transfer interactions and incomplete complexation of the solute; these effects are averaged out in the derived beta and pi parameters and thus limit their applicability.

View Article: PubMed Central - HTML - PubMed

Affiliation: Chemistry Department, UAE University, Al-Ain, UAE. raufmapk@yahoo.com

ABSTRACT

Background: The study was aimed at investigating the effect of various solvents on the absorption spectra of Neutral Red, a dye belonging to the quinone-imine class of dyes. The solvents chosen for the study were water, ethanol, acetonitrile, acetone, propan-1-ol, chloroform, nitrobenzene, ethyleneglycol, acetic acid, DMSO and DMF.

Results: The results have shown that the absorption maxima of dyes are dependent on solvent polarity. In non-hydrogen-bond donating solvents, solvation of dye molecules probably occurs via dipole-dipole interactions, whereas in hydrogen-bond donating solvents the phenomenon is more hydrogen bonding in nature. To estimate the contribution of the different variables on the wave number of the Neutral Red dye, regression analyses using the ECW model were compared with the pi* scale model. This showed that the unified scale for estimating the solvent effect on the absorption of the Neutral Red dye is more adopted and more applicable than the pi* scale model.

Conclusion: Absorption maxima of dyes are dependent on solvent polarity. Solvation of dye molecules probably occurs via dipole-dipole interactions in non-hydrogen-bond donating solvents, whereas in hydrogen-bond donating solvents the phenomenon is more hydrogen bonding in nature. The unified scale for estimating the solvent effect on the absorption of Neutral Red dye is more adopted and more applicable than the pi* scale model. This may be due to complications from both pi-pi* charge transfer interactions and incomplete complexation of the solute; these effects are averaged out in the derived beta and pi parameters and thus limit their applicability.

No MeSH data available.


Related in: MedlinePlus