New version of the semiempirical theory of the effect of the dielectric properties of individual solvents on the shift of the absorption spectra of solutions

Bakhshiev, N. G.

doi:10.1364/jot.68.000184

Cited by 6 publications

(5 citation statements)

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“…The dipole moment µ g increases linearly (see Fig. 2) with an increase in the medium polarity function f(ε) = (ε -1)/(2ε + 1), as is expected from the Onsager theory 6 .…”

Section: Resultssupporting

confidence: 73%

4-Dimethylaminochalcone as a f luorescent probe: Quantum chemical calculations of its interaction with the environment

et al. 2006

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Ground state RHF/6 311G(d,p) and density functional B3LYP/6 311G(d,p) quantum chemical calculations of 4 dimethylaminochalcone (DMAC), a sensitive fluorescent probe, were carried out for vacuum and for solvents of different polarity. The effect of the medium was included by the SCRF method in the framework of the polarization continuum model. The DMAC fragment comprising the aniline and propenone groups has a nearly planar conforma tion. The phenyl group can lie in the same plane or rotate by an angle within the limits of ±20°w ith a low barrier at 293 K. The results of calculations were confirmed by the data of X ray study, according to which the phenyl group in the crystal is rotated by 20°. Calculations with allowance for solvation effects predict charge transfer from the dimethylamino group to the oxygen atom; the higher the medium polarity, the larger the degree of charge transfer (atomic charge of oxygen increases by 0.07 e in acetone). The calculated dipole moment of the DMAC molecule increases from 5.2 D (vacuum) to 5.9 D (heptane) and 6.9 D (acetone), which is in agreement with spectroscopic data. The energy of the DMAC-environment interaction was calculated. Due to large dipole moment of the DMAC molecule, the electrostatic component of this energy strongly depends on the environment polarity, which can be related to redistribu tion of the probe between the aqueous phase and cells and lipid structures of lipoproteins. The electronic absorption spectra of DMAC in solvents of different polarity were calculated; differences between the calculated and experimentally measured values are at most 15 nm.

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“…The dipole moment µ g increases linearly (see Fig. 2) with an increase in the medium polarity function f(ε) = (ε -1)/(2ε + 1), as is expected from the Onsager theory 6 .…”

Section: Resultssupporting

confidence: 73%

4-Dimethylaminochalcone as a f luorescent probe: Quantum chemical calculations of its interaction with the environment

et al. 2006

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“…The excited state dipole moment can be calculated from the solvatochromic shifts of the absorption and fluorescence spectra by the solvatochromic method, ,− which involves inexpensive equipment and reflects the effect of electric field on the displacement of the absorption and emission bands. Solvatochromic shifts in absorption only give information on the variation of solvation energy occurring immediately after the molecular excitation, thus not reflecting time averaged effects that would eventually result from subsequent events.…”

Section: Resultsmentioning

confidence: 99%

Combined Theoretical and Experimental Study of the Photophysics of Asulam

et al. 2013

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The photophysics of the neutral molecular form of the herbicide asulam has been described in a joint experimental and theoretical, at the CASPT2 level, study. The unique π → π* aromatic electronic transition (f, ca. 0.5) shows a weak red-shift as the polarity of the solvent is increased, whereas the fluorescence band undergoes larger red-shifts. Solvatochromic data point to higher dipole moment in the excited state than in the ground state (μ(g) < μ(e)). The observed increase in pKa in the excited state (pKa* - pKa, ca. 3) is consistent with the results of the Kamlet-Abboud-Taft and Catalán et al. multiparametric approaches. Fluorescence quantum yield varies with the solvent, higher in water (ϕ(f) = 0.16) and lower in methanol and 1-propanol (approx. 0.02). Room temperature fluorescence lifetime in aqueous solution is (1.0 ± 0.2) ns, whereas the phosphorescence lifetime in glassy EtOH at 77 K and the corresponding quantum yield are (1.1 ± 0.1) s and 0.36, respectively. The lack of mirror image symmetry between modified absorption and fluorescence spectra reflects different nuclear configurations in the absorbing and emitting states. The low value measured for the fluorescence quantum yield is justified by an efficient nonradiative decay channel, related with the presence of an easily accessible conical intersection between the initially populated singlet bright (1)(L(a) ππ*) state and the ground state (gs/ππ*)(CI). Along the main decay path of the (1)(L(a) ππ*) state the system undergoes an internal conversion process that switches part of the population from the bright (1)(L(a) ππ*) to the dark (1)(L(b) ππ*) state, which is responsible for the fluorescence. Additionally, singlet-triplet crossing regions have been found, a fact that can explain the phosphorescent emission detected. An intersystem crossing region between the phosphorescent state (3)(L(a) ππ*) and the ground state has been characterized, which contributes to the nonradiative deactivation of the excitation energy.

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“…This effect is a consequence of the fact that the solvatochromic data are correlated with coefficient a KT rather than p* KT and that, in the aprotic solvent set, only ACN and acetone have non-zero a KT values. Anyhow, the best correlation coefficients are obtained for the polar aprotic set (4,(8)(9)(10)(11)(12), which is thus relevant for a physical treatment of solvatochromism. This group of solvents can be considered as electrostatic, because p 4 a and b (even if a and b are still not negligible).…”

Section: V3 the Solvatochromic Analysis Of Sbpamentioning

confidence: 99%

“…It is known that experimental estimation of excited state dipole moments can be provided from solvatochromic analysis. [8][9][10][11][12][13] Surprisingly, although this type of analysis needs inexpensive equipment, a thoughtful solvatochromism study of SBPa has never been reported except for some sparse data. 14 In general, the procedure for analyzing solvatochromic data, first proposed by Lippert and Mataga, [15][16][17][18] consists in evaluating Dm through a plot of the Stokes shift as a function of a solvent polarity parameter and deducing m e from a second independent measurement of m g by conventional electrotechnics.…”

Section: Introductionmentioning

confidence: 99%

“…Practically, it is a challenging task that is much debated in the literature. 8,[19][20][21][22] One can be easily convinced of this problem through the very recent controversy about the polarizability difference Da = a g À a e in Reichardt's betaine B30. 19,20 Thus, it is not surprising that most often this parameter is not considered at all or simply approximated to a dimensionless constant value a g = a e = k/a 0 3…”

Section: Introductionmentioning

confidence: 99%

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The excited state dipole moments of betaine pyridinium investigated by an innovative solvatochromic analysis and TDDFT calculations

Pawlowska

Lietard

Aloïse

et al. 2011

Phys. Chem. Chem. Phys.

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This work reports on the solvatochromic properties of a simple heterocyclic betaine pyridinium, 2-(1-pyridinio)benzimidazolate (SBPa), having promising potentialities in non-linear optics. From advanced PCM-TDDFT calculations, the solvatochromism of SBPa was found to be unusual, involving two different electronic states for absorption (S(0)→ S(2)) and emission (S(1)→S'(0)). To account for this behavior, we developed an innovative physical treatment which consists in a non-linear fit of the solvatochromic data using the Bilot-Kawski theoretical model and visualizing the least-square coefficient χ(2) on a 2D map as a function of the solute polarizability and gas phase absorption energy. In parallel, Kamlet-Taft correlations were undertaken to select a propitious set of electrostatic solvents usable in this treatment. Protic solvents that lead to specific interactions and nonpolar solvents that favor dimerization processes were excluded. From a choice of aprotic solvents with sufficiently high polarity, 4 dipole moments μ(g)(S(0)) = +9.1 D, μ(e)(S(2)) = -1.5 D, μ(e)(S(1)) = 0 D and μ(g)(S'(0)) = +3.31 D were determined, the 3 former values being in close agreement with TDDFT values, although the solute polarizability values seem underestimated. Anyhow, disregarding this discrepancy, we evaluated the static hyperpolarizability to β(0) = -64 × 10(-30) esu from the solvatochromic data in close agreement with DFT calculations.

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New version of the semiempirical theory of the effect of the dielectric properties of individual solvents on the shift of the absorption spectra of solutions

Cited by 6 publications

References 0 publications

4-Dimethylaminochalcone as a f luorescent probe: Quantum chemical calculations of its interaction with the environment

4-Dimethylaminochalcone as a f luorescent probe: Quantum chemical calculations of its interaction with the environment

Combined Theoretical and Experimental Study of the Photophysics of Asulam

The excited state dipole moments of betaine pyridinium investigated by an innovative solvatochromic analysis and TDDFT calculations

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