Ultrafast Solvation Dynamics of Coumarin 153 in Imidazolium-Based Ionic Liquids

Lang, Bernhard Felix; Angulo, Gonzalo; Vauthey, Eric

doi:10.1021/jp057482r

Cited by 101 publications

(125 citation statements)

References 34 publications

(65 reference statements)

Supporting

Mentioning

118

Contrasting

Order By: Relevance

“…The observed fluorescence time profile, D(λ,t), could be reproduced by the convolution of the Gaussian-shaped IRF with a trial function, which, in our case, was a sum of one Gaussian and several exponential terms. The convolution of a Gaussian function (IRF) with another Gaussian function, D IXG (λ,t), or with an exponential function, D IXE (λ,t), 16 leads respectively to the following analytical expressions:…”

Section: Methodsmentioning

confidence: 99%

Ultrafast Excited-State Dynamics of Oxazole Yellow DNA Intercalators

Fürstenberg

Vauthey

2007

J. Phys. Chem. B

Self Cite

View full text Add to dashboard Cite

The excited-state dynamics of the DNA intercalator YO-PRO-1 and of three derivatives has been investigated in water and in DNA using ultrafast fluorescence spectroscopy. In the free form, the singly charged dyes exist both as monomers and as H-dimers, while the doubly charged dyes exist predominantly as monomers. Both forms are very weakly fluorescent: the monomers because of ultrafast nonradiative deactivation, with a time constant on the order of 3-4 ps, associated with large amplitude motion around the methine bridge, and the H-dimers because of excitonic interaction. Upon intercalation into DNA, large amplitude motion is inhibited, H-dimers are disrupted, and the molecules become highly fluorescent. The early fluorescence dynamics of these dyes in DNA exhibits substantial differences compared with that measured with their homodimeric YOYO analogues, which are ascribed to dissimilarities in their local environment. Finally, the decay of the fluorescence polarization anisotropy reveals ultrafast hopping of the excitation energy between the intercalated dyes. In one case, a marked change of the depolarization dynamics upon increasing the dye concentration is observed and explained in terms of a different binding mode.

show abstract

Section: Methodsmentioning

confidence: 99%

Ultrafast Excited-State Dynamics of Oxazole Yellow DNA Intercalators

Fürstenberg

Vauthey

2007

J. Phys. Chem. B

Self Cite

View full text Add to dashboard Cite

show abstract

“…5 Moreover, it has been found that solvent dependence of ultrafast solvation dynamics of Ox4 in conventional molecular liquids cannot be described by dielectric relaxation based theories. [6][7][8][9][10] DSS measurements, on the other hand, have employed dipolar chromophores such as coumarin 153 (C153), 3,[11][12][13][14] 4aminophthalimide (4AP), 15 and trans-4-dimethylamino-4 -cyanostilbene (DCS), 2 which undergo large dipole moment changes upon excitation. As a result, Stokes shift values for these probes in phosphonium and imidazolium ionic liquids have been found to be approximately an order of magnitude larger than those with Ox4, and dynamic response explainable by a semi-molecular theory [16][17][18][19][20][21] that uses experimental dielectric relaxation data [22][23][24][25] as inputs.…”

Section: Introductionmentioning

confidence: 99%

Ultrafast solvation response in room temperature ionic liquids: Possible origin and importance of the collective and the nearest neighbour solvent modes

Daschakraborty

Biswas

2012

The Journal of Chemical Physics

View full text Add to dashboard Cite

Recent three-pulse photon echo peak shift (3PEPS) measurements [M. Muramatsu, Y. Nagasawa, and H. Miyasaka, J. Phys. Chem. A 115, 3886 (2011)] with several room temperature ionic liquids (RTILs) have revealed multi-exponential dynamics with ultrafast solvation timescale in the range, 20 < τ(1)∕fs < 250, for both imidazolium and phosphonium RTILs. This is striking for two reasons: (i) the timescale is much faster than those reported by the dynamic Stokes shift (DSS) experiments [S. Arzhantsev, H. Jin, G. A. Baker, and M. Maroncelli, J. Phys. Chem. B 111, 4978 (2007)] and (ii) sub-hundered femtosecond solvation response in phosphonium ionic liquids is reported for the first time. Here, we present a mode coupling theory based calculation where such ultrafast solvation in 3PEPS measurements has been visualized to originate from the nearest neighbour solute-solvent interaction. Consideration of Lennard-Jones interaction for the nearest neighbour solute-solvent non-dipolar interaction leads to biphasic dynamics with a predicted ultrafast time constant in the ∼100-250 fs range, followed by a slower one similar to that reported by the 3PEPS measurements. In addition, the calculated fast time constants and amplitudes are found to be in general agreement with those from computer simulations. Different microscopic mechanisms for ultrafast solvation response measured by the 3PEPS and DSS experiments have been proposed and relative contributions of the collective and nearest neighbour solvent modes investigated. Relation between the single particle rotation and ultrafast polar solvation in these RTILs has been explored. Our analyses suggest 3PEPS and DSS experiments are probably sensitive to different components of the total solvation energy relaxation of a laser-excited dye in a given ionic liquid. Several predictions have also been made, which may be re-examined via suitable experiments.

show abstract

“…In particular, negligible vapor pressure of RTILs makes them a green alternative of conventional organic solvent. For understanding of RTIL's dynamical behavior at the molecular level, solvation and rotational dynamics have been studied experimentally Cang et al, 2003;Funston et al, 2007;Ingram et al, 2003;Jin et al, 2007;Karmakar & Samanta, 2002a;Lang et al, 2006) and theoretically Kobrak, 2006;2007;Kobrak & Znamenskiy, 2004;Shim et al, 2006;2007;Shim & Kim, 2009). It is found that the ultrafast relaxation in a subpicosecond time regime contributes substantially to solvation dynamics, disproving the diffusion-controlled solvation in RTILs.…”

Section: Introductionmentioning

confidence: 99%