Investigations of the Solvent Polarity Effect on the Photophysical Properties of Coumarin‐7 Dye<sup>¶</sup>

Satpati, Ashish; Senthilkumar, S.; Kumbhakar, Manoj; Nath, Sukhendu; Maity, Dilip Kumar; Pal, Haridas

doi:10.1111/j.1751-1097.2005.tb00184.x

Cited by 18 publications

(34 citation statements)

References 49 publications

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“…The poo. tophysical properties of laser dyes were found to be highly sensitive to the nature of solvents and UJ the environments [11,[14][15][16]. The polarity of solvents, their viscosity, and dielectric constants are found 10 be critical in the photochemical behavior of laser dyes.…”

Section: Resultsmentioning

confidence: 99%

“…Strong polarity-dependent Stokes's shifts are observed in many coumarin derivatives [11][12][13][14][15][16]. The 7-NEt2 coumarin dyes are seen to exhibit quite unusual behavior in certain nonpolar solvents.…”

Section: Introductionmentioning

confidence: 93%

“…The 7-NEt2 coumarin dyes are seen to exhibit quite unusual behavior in certain nonpolar solvents. It is reported that the dye adopts different conformations of this group in nonpolar and some other solvents [11][12][13]. A linear relation is reported between quantum yield and solvent polarity for moderate to high polarity solvents but it deviates to higher values in nonpolar solvents [16].…”

Section: Introductionmentioning

confidence: 96%

“…Recently coumarin dyes have been introduced as dopants in electrically excited organic light emitting diodes (OLED). They have also been successfully introduced in high-brightness OLED devices [11,12].…”

Section: Introductionmentioning

confidence: 99%

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Study of solvent effect in laser emission from Coumarin 540 dye solution

et al. 2007

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The results of a brief investigation of the amplified spontaneous emission and lasing characteristics of Coumarin 540 dye in as many as ten different solvents are reported. It has been found that C 540 dye solutions contained within a rectangular quartz cuvette give laser emission with well resolved equally spaced modes when pumped with a 476 nm beam. The modes were found to originate from the subcavities formed by the plane-parallel walls of the cuvette containing the high-gain medium. While the quantum yield remains a decisive factor, a clear correlation between the total width of the emission spectra and the refractive indices of the solvents of the respective samples has been demonstrated. The well-resolved mode structure exhibited by the emission spectra gives clear evidence of the lasing action taking place in the gain medium, and the number of modes enables us to compare the gain of the media in different samples. A detailed discussion of the solvent effect in the lasing characteristics of C540 in different solutions is given.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 93%

Section: Introductionmentioning

confidence: 96%

Section: Introductionmentioning

confidence: 99%

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Study of solvent effect in laser emission from Coumarin 540 dye solution

et al. 2007

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“…The values of the slope, 2( E Ϫ G ) 2 /hca 3 and the intercept were obtained by fitting the spectral results of Nile red in a series of water/EtOH mixtures of the bulk solution by eq 3. The dielectric constant MS and refractive index n MS of a water/EtOH mixture can be calculated by the following equations [46]:…”

Section: Quantitative Analysis Of the Solvent Polarity Changes In Thementioning

confidence: 99%

Evolution of the solvent polarity in an electrospray plume

Wang

Zenobi

2010

J. Am. Soc. Mass Spectrom.

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Solvent polarity plays an important role in electrospray ionization-mass spectrometry (ESI-MS), one of the most widely used analytical methods for biochemistry. To have a comprehensive understanding of how solvent polarity affects ESI-MS measurements, we systematically investigated the polarity change in the ESI plume formed from an ethanol solution using laser-induced fluorescence (LIF) spectroscopy. Two solvatochromic dyes (i.e., dyes whose fluorescence emission is sensitive to solvent polarity), Nile red and DCM (4-dicyanomethylene-2-methyl-6-p-dimethylaminostyryl-4H-pyran), were used as probes. The peak emission wavelengths of these two dyes exhibited significant red shifts (8 -12 nm) when the measuring spot was moved away from the spray tip and in radial direction in the plume, indicating a dramatic polarity change during shrinking of the droplets. The emission intensities were also measured with a polarity-insensitive dye as a reference. The results are consistent with the peak wavelength measurements. Two key mechanisms responsible for the change of solvent polarity in the plume were considered, water entrainment from the surrounding air and solvent evaporation. Furthermore, quantitative analysis of the solvent polarity change was performed by using the Lippert-Mataga polarity parameter ⌬f. The value of ⌬f reached 0.305-0.307 at the periphery of the ESI plume, which means that the solvent polarity in the smaller droplet is close to that of a mixture of 30% water and 70% ethanol (⌬f ϭ 0.307), even though the bulk solvent was ethanol containing less than 1% water as an impurity. (J Am Soc Mass Spectrom 2010, 21, 378 -385) © 2010 American Society for Mass Spectrometry E lectrospray ionization-mass spectrometry (ESI-MS) is widely used in many important fields, e.g., biochemistry, the food industry, and pharmacy, and is still under fast development. Despite its huge success, only relatively few fundamental studies on the mechanism of ESI have been undertaken: the different modes of the electrospray [1, 2], partitioning effects in sprayed droplets [3][4][5], size, charge, and mass changes of the droplets during solvent evaporation [6 -11], chemical equilibria in the electrospray process [12][13][14], and ion formation from the droplets [15][16][17][18][19][20] have been studied. However, more fundamental studies are still needed to make ESI-MS a totally reliable method for wider applications.In this work, we focus on one fundamental aspect of the ESI process, the solvent polarity in the ESI plume. As one of the most basic physical properties, solvent polarity controls the rates of chemical reactions [21,22] and chemical equilibria [23,24] in solution, which have been widely studied by ESI-based techniques [25][26][27]. Especially, solvent polarity can have significant effects on biomolecules. For example, the charge state of biomolecules in ESI mass spectra can vary with solvent polarity [28,29]. The solvent polarity also influences protein conformation [30], the stability of enzymes [31], and the structural ch...

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Effect of H‐Bonding on the Photophysical Behaviour of Coumarin Dyes

Nath

Kumbhakar

Pal

2010

Hydrogen Bonding and Transfer in the Excited State

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The Lippert-Mataga [1, 2] expression is the most generalized equation used to describe the solvent-dependent spectral shifts of many chromophoric molecules. The Lippert-Mataga equation considers mainly two characteristic factors of the solvents, namely the refractive index (n) and the static dielectric constant («). According to the Lippert-Mataga representation, a chromophore should show bathochromic shifts in the absorption and emission spectra and a linear increase in the Stokes shift with increasing solvent polarity parameter, Df (Df ¼ [(« À 1)/(2« þ 1) À (n 2 À 1)/(2n 2 þ 1)]). This general solvent effect predicted by the Lippert-Mataga equation is expected to be independent of the chemical properties of the chromophore and the solvent used.Besides its extensive use, the Lippert-Mataga equation fails to predict the spectral properties of several chromophores in different solvent environments [3][4][5][6][7][8]. This failure is mainly due to the presence of specific interactions of the chromophores with their surrounding solvent molecules. These specific interactions can arise owing to different mechanisms such as preferential solvation [9-11], charge transfer interaction [12], hydrogen bonding interaction [13][14][15], etc. The changes in spectral characteristics experienced by a chromophore owing to its specific interaction with the surrounding solvent can sometimes be much more prominent than those expected from the general solvent effect as predicted by the Lippert-Mataga equation. For example, N-phenyl-2-aminonaphthalene shows a structured emission spectrum in a non-polar solvent such as cyclohexane. However, the structures in the emission spectrum disappear, and the emission maxima undergo a large shift on the addition of just $0.2% of ethanol in the cyclohexane solution of the dye [16]. Further, it is seen that the spectrum of N-phenyl-2-aminonaphthalene in 3% ethanolic solution is only marginally different from that observed in the neat ethanol solution. Such a small amount of ethanol in

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Investigations of the Solvent Polarity Effect on the Photophysical Properties of Coumarin‐7 Dye^¶

Cited by 18 publications

References 49 publications

Study of solvent effect in laser emission from Coumarin 540 dye solution

Study of solvent effect in laser emission from Coumarin 540 dye solution

Evolution of the solvent polarity in an electrospray plume

Effect of H‐Bonding on the Photophysical Behaviour of Coumarin Dyes

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Investigations of the Solvent Polarity Effect on the Photophysical Properties of Coumarin‐7 Dye¶

Cited by 18 publications

References 49 publications

Study of solvent effect in laser emission from Coumarin 540 dye solution

Study of solvent effect in laser emission from Coumarin 540 dye solution

Evolution of the solvent polarity in an electrospray plume

Effect of H‐Bonding on the Photophysical Behaviour of Coumarin Dyes

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Investigations of the Solvent Polarity Effect on the Photophysical Properties of Coumarin‐7 Dye^¶