Characterization of the fluorescence emission properties of prodan in different reverse micellar environments

Sengupta, Bidisa; Guharay, Jayanti; Sengupta, Pradeep K.

doi:10.1016/s1386-1425(00)00245-6

Cited by 60 publications

(67 citation statements)

References 28 publications

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“…3) suggest that it is predominantly located at the C 12 E 5 /water boundary, but also shows (see short wavelength shoulder) some tendency to sit in a hydrocarbon rich region. Studies in reverse micelles using this probe also point to multiple partitioning sites [11,12].…”

Section: Resultsmentioning

confidence: 98%

Solvatochromic fluorescent probes in bicontinuous microemulsions

Oliveira

Hungerford

Miguel

2001

Journal of Molecular Structure

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The¯uorescence probes nile red and prodan have been used to study the structure of the bicontinuous phase of C 12 E 5 /alkane/ water microemulsions. For nile red the steady state¯uorescence spectrum show contributions from probe located in alkane and surfactant rich regions, together with indications of surfactant hydration. Fluorescence lifetime measurements show multiexponential decay kinetics consistent with this idea. The steady state¯uorescence spectrum of prodan in the bicontinuous region also suggests different environments for the probe. Fluorescence anisotropy measurements using rhodamine 6G show that this bicontinuous phase is more ordered than either oil in water or water in oil microemulsions. The¯uorescence technique provides a valuable tool with which to elucidate the structure of these complex systems. q

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Section: Resultsmentioning

confidence: 98%

Solvatochromic fluorescent probes in bicontinuous microemulsions

Oliveira

Hungerford

Miguel

2001

Journal of Molecular Structure

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“…Positive charge in the ground state of prodan is localized on C atoms of the aromatic ring (for atom numbering, see Possible applications of the studied fluorescent probes include the estimation of solvent polarity. This has been done for prodan [24] although for only a few (5) solvents. Fluorescence band maxima for several solvents were plotted as a function of polarity parameters of the actual solvent (polarity scale) using a large amount of data for prodan fluorescence spectra.…”

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confidence: 99%

Effect of proton-donor solvent and structural flexibility of prodan and laurdan molecules on their spectral-luminescent properties

et al. 2009

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535.37The influence of structural flexibility on dipole moments, energy-level locations, and charge distributions in prodan and laurdan molecules was studied. A quantum-chemical calculation of isolated prodan and laurdan molecules in the fluorescent state geometry was conducted. Rate constants for radiative and non-radiative processes and fluorescence quantum yields for these probe molecules were calculated. Interaction centers of prodan and laurdan with a proton-donor solvent were estimated quantitatively. The possibility of using fluorescent probes for estimating the polarity of proton-donor and proton-acceptor solvents was shown.Keywords: fluorescent probe, prodan, laurdan, structural flexibility, proton-donor properties, fluorescence quantum yield.Introduction. Fluorescent probes such as prodan (6-propionyl-2-dimethylaminonaphthalene) and laurdan (6-dodecanoyl-2-dimethylaminonaphthalene) are widely used in biological and biophysical research [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15]. The fluorescence properties of prodan and laurdan have been described in the literature as simultaneously existing local-excited (LE) and twisted internal charge-transfer (TICT) states. However, the latter term should be used very arbitrarily because the state has been observed only at very low temperatures [2]. These states are strongly delocalized at temperatures near ambient and above [2]. It has been shown [5] that the positions of fluorescence maxima in phospholipids bilayers depend on the phase state of the phospholipids, i.e., 435 and 440 nm for the short-wavelength band in the gel phase; 515 and 490 nm, for prodan and laurdan in the liquid-crystalline phase. Two fluorescence bands (430 and 500 nm) were observed for laurdan in glycerin with λ ex = 380 nm at room temperature. The short-wavelength band at 430 nm disappeared as the temperature was raised to 370 K.The large shifts of prodan and laurdan fluorescence bands in solvents of different polarity have been explained by the significant change of dipole moment in the excited state as compared with the ground state. According to formulas for calculating common effects of solvents [16,17], changing the prodan dipole moment from 5.5 to 10.2 D causes a shift of the S 0 → S 1 -transition [18,19] in its fluorescence spectra of 770 cm -1 and 800 cm -1 on going to isopropanol and water, respectively, from a non-polar solvent [19,20]. The experimental shifts in fluorescence spectra of prodan were 3790 and 5520 cm -1 in isopropanol and water, i.e., the size of the dipole moment and its change from

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“…A variety of parameters such as binding constant, aggregation number, etc. can be determined [6][7][8]. The quenching of AO by organodiselenides at fixed surfactant concentration (0.45 M) and at x = 25 has been studied to find out the parameters such as Stern-Volmer constant, aggregation number and probable location of organodiselenides in the microemulsion media.…”

Section: Fluorescence Spectroscopymentioning

confidence: 99%

“…Fluorescence and UV-visible absorption spectroscopy [6][7][8] methods are widely used to investigate the properties of microemulsions due to their suitable time scale, non-invasive nature and intrinsic sensitivity. FTIR, 1 H NMR [9][10][11][12] and physicochemical investigations [9][10][11][12][13][14][15] have shown that the polar solvents when restricted to the nanometer-scale core behave differently from the bulk solvent as a result of the specific interactions and confined geometries.…”

Section: Introductionmentioning

confidence: 99%