Fluorescence Anisotropy Decay and Solvation Dynamics in a Nanocavity:  Coumarin 153 in Methyl β-Cyclodextrins

Sen, Pratik; Roy, Durga; Mondal, Sudip Kumar; Sahu, Kalyanasis; Ghosh, Subhadip; Bhattacharyya, Kankan

doi:10.1021/jp051607a

Cited by 90 publications

(96 citation statements)

References 71 publications

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“…The hydrodynamic diameter (2r h ) of 1:2 complex is roughly equal to the sum of height of two CD cavities. 13 Most recently, Roy et al observed an extremely slow anisotropy decay (time constant >20 ns) for the C153--cyclodextrin guest-host complex (Fig. 11).…”

Section: Fluorescence Anisotropy Decaymentioning

confidence: 93%

“…Sen et al measured anisotropy decay of C153 inside di-and tri-methyl -CD. 13 They observed a bi-exponential decay with components 1000-1150 and 2500-2700 ps. They ascribed the components respectively to the 1:1 and 1:2 complex of C153 with cyclodextrin (Fig.…”

Section: Fluorescence Anisotropy Decaymentioning

confidence: 97%

“…Recently, Sen et al studied the effect of methyl substitution of cyclodextrin on ultrafast solvation dynamics. 13 In trimethyl -CD, all the three OH groups of the -CD cavity are replaced by OMe groups. It is observed that solvation dynamics in trimethyl -CD displays two very slow components-240 ps (45%) and 2450 ps (31%) along with a fast component of 10 ps (24%) (Fig.…”

Section: Solvation Dynamicsmentioning

confidence: 99%

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Ultrafast Dynamics in Biological Systems and in Nano-Confined Environments

Sahu

Mondal

Ghosh

et al. 2007

Bulletin of the Chemical Society of Japan

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Ultrafast chemical dynamics in a nano-confined system is very different from that in a bulk liquid. In this account, we give an overview on recent femtosecond study on dynamics of ultrafast chemical processes in the nanocavity of a biological system. Dynamics in a biological system crucially depends on the location of the fluorescent probe. We show that one can study solvation dynamics in different regions (i.e. spatially resolve) by variation of the excitation wavelength. We discuss two interesting cases of how structure affects dynamics. First, solvation dynamics of two protein folding intermediates of cytochrome c is found to be differ significantly in the ultrafast initial part (<20 ps). Second, methyl substitution of the OH group in a cyclodextrin is shown to slow down the initial part of solvation dynamics quite dramatically. The most interesting observation is the discovery of the ultraslow component of solvation dynamics which is 100-1000 times slower compared to bulk water. The electron-and proton-transfer processes in a nano-confined system are found to be markedly retarded because of slow solvation and structural constraints. Close proximity of the reactants in a confined system is expected to accelerate dynamics of bi-molecular processes. This is illustrated by ultrafast fluorescence resonance energy transfer (FRET) in %1 ps time scale between a donor and an acceptor in a micelle. Finally, it is demonstrated that the decay of fluorescence anisotropy provides structural information (e.g. size of a cyclodextrin inclusion complex) and may be used to detect formation of a nano-aggregate.

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Section: Fluorescence Anisotropy Decaymentioning

confidence: 93%

Section: Fluorescence Anisotropy Decaymentioning

confidence: 97%

Section: Solvation Dynamicsmentioning

confidence: 99%

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Ultrafast Dynamics in Biological Systems and in Nano-Confined Environments

Sahu

Mondal

Ghosh

et al. 2007

Bulletin of the Chemical Society of Japan

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“…CDs are well-known in their ability to form inclusion complexes with hydrophobic molecules in aqueous solution and a number of studies have been performed about photochemical properties of the CD complexes including fluorescent probes such as pyrene, anthracene, coumarin and their derivatives [3][4][5][6][7][8][9][10][11][12][13][14][15].…”

Section: Introductionmentioning

confidence: 99%

Spectral Narrowing of UV-Visible Absorption and Emission Spectra of Anthracene-Derivatives in β-Cyclodextrin Nanocavity: Effects of Host/Guest Stoichiometry

Sato

Yoshizumi

Kiba

et al. 2012

Molecular Crystals and Liquid Crystals

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Cyclodextrins (CD) are cyclic oligosaccharides consisting of six or more D-glucopyranose units, the interior of which forms a hydrophobic cavity. In the present study, we employed the CD confinement effects as a tool to suppress an electronic decoherence of guest wavefunction by reducing intermolecular interactions between a guest molecule and the surrounding environment.Effects of host/guest stoichiometry on the decoherence suppresion were investigated by comparing native -CD with trimethyl--CD that should form only a 1:1 complex. Both fluorecence and fluorecence-excitation spectra of inclusion complexes exhibited spectral narrowings only for the -CD host, suggesting that the formation of barrel-type -CD dimer plays a key role for the pronounced spectral narrowings.

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“…The number of species of inclusion complexes present in solution can be determined from fluorescence anisotropy decay. [9] The anisotropy decay profile of perylene in g-CD shows a single-exponential decay, which suggests that there is only one type of inclusion complexlikely to be the 1:2 complex (judging from the pH dependence of the fluorescence intensity). This fact is consistent with the behavior of a 1:2 complex previously reported.…”

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confidence: 99%

Cyclodextrin Nanocavity Caging Effect on Electronic Dephasing

et al. 2008

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The ability to control molecular wavefunctions may lead to novel quantum technologies, such as bond-selective chemistry and quantum computing. [1][2][3] An understanding of the coherent-loss process is essential for the realization of these quantum technologies using quantum-interference (QI) effects in condensed media. Although the overwhelming majority of chemical reactions take place in solution, there have been very few experimental studies on the coherent reaction control of polyatomic molecules in condensed media, because of the rapid decoherence of wavefunctions. These fast quantumphase relaxations are thought to be caused by solute-solvent interactions. [4,5] Thus, an understanding of the roles of solvent molecules in the dephasing mechanism is strongly required. It is noted that the inhibition of dephasing is necessary for the development of coherent control techniques for more general reactions. Therefore, the protection of molecular wavefunctions from the surrounding environment becomes an important issue for the realization of quantum-control techniques in condensed phases. Here, we aimed to protect the quantum phase of a guest molecule by using the size-fit nanospace of a cyclodextrin nanocavity.Cyclodextrins (a-, b-, or g-CD), which are oligosaccharides with hydrophobic interiors and hydrophilic exteriors, are used as nanocavities. The ability of CDs to encapsulate organic and inorganic molecules in aqueous solution has led to intensive studies of their inclusion complexes.[6] We intuitively imagined that the confinement of a guest molecule within the CD nanocavity would reduce perturbations from the surrounding environment, which cause the decoherence. Several studies on CD complexes with aromatic compounds, performed using timeresolved spectroscopy, have been reported. [6][7][8][9][10][11][12][13] To our knowledge, however, no experiments have been reported on CD inclusion to suppress decoherence. As far as we know, this is the first report on the CD encapsulation effect that moderates the decoherence of the molecular wavefunction at room temperature.Herein, we report the moderation of electronic decoherence of perylene in g-CD at room temperature, as measured by an optical-phase-controlled pulse-pair quantum interferometer, [14][15][16][17][18][19][20][21][22][23] combined with spectral lineshape analysis. A method to induce QI of molecular wavefunctions by a pair of phaselocked pulses has been originally developed by Scherer et al. and successfully applied to I 2 molecules in the gas phase. [14] The QI technique was successfully applied to various systems, such as GaAs quantum dots, [15,16] ZnSe films, [17] the Rydberg atom, [18,19] Cl 2 in an Ar matrix, [20] I 2 in the gas phase, [21,22] and a microcrystalline powder of a linked anthracene dimer.[23] Figure 1 shows the steady-state fluorescence and fluorescence-excitation spectra of perylene in both a g-CD aqueous solution and a tetrahydrofuran (THF) solution. Because of the low solubility of perylene in water (ca. 1.6 10 À9 m), [24] we could n...

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Fluorescence Anisotropy Decay and Solvation Dynamics in a Nanocavity: Coumarin 153 in Methyl β-Cyclodextrins

Cited by 90 publications

References 71 publications

Ultrafast Dynamics in Biological Systems and in Nano-Confined Environments

Ultrafast Dynamics in Biological Systems and in Nano-Confined Environments

Spectral Narrowing of UV-Visible Absorption and Emission Spectra of Anthracene-Derivatives in β-Cyclodextrin Nanocavity: Effects of Host/Guest Stoichiometry

Cyclodextrin Nanocavity Caging Effect on Electronic Dephasing

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