Temperature Dependence of the Fluorescence Properties of Thioflavin-T in Propanol, a Glass-Forming Liquid

Amdursky, Nadav; Gepshtein, Rinat; Erez, Yuval; Huppert, Dan

doi:10.1021/jp1121195

Cited by 40 publications

(92 citation statements)

References 33 publications

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“…115 For η ∼ 1cP, V ∼ 30 Å 3 , F ∼ 0.1 eV/rad, this implies τ ∼ 1 ps, which is the right order of magnitude for many chromophores. The relation above implies that the lifetime scales linearly with the viscosity, which has been observed over four orders of magnitude for thioflavin-T. 115 However, many chromophores, including GFP chromophore models, 20,116,117 exhibit non-radiative lifetimes with sub-linear fractional power law dependence on viscosity, η α . 118 For GFP models, the value of α has been estimated at ∼0.5, 116, 117 but other work indicated a lower value of ∼0.25.…”

Section: Excited-state Driving Forces and Channel-specific Excitedmentioning

confidence: 95%

A two-state model of twisted intramolecular charge-transfer in monomethine dyes

Olsen

McKenzie

2012

The Journal of Chemical Physics

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Articles you may be interested inModeling opto-electronic properties of a dye molecule in proximity of a semiconductor nanoparticle J. Chem. Phys. 139, 024105 (2013) A two-state model Hamiltonian is proposed, which can describe the coupling of twisting displacements to charge-transfer behavior in the ground and excited states of a general monomethine dye molecule. This coupling may be relevant to the molecular mechanism of environment-dependent fluorescence yield enhancement. The model is parameterized against quantum chemical calculations on different protonation states of the green fluorescent protein chromophore, which are chosen to sample different regimes of detuning from the cyanine (resonant) limit. The model provides a simple yet realistic description of the charge transfer character along two possible excited state twisting channels associated with the methine bridge. It describes qualitatively different behavior in three regions that can be classified by their relationship to the resonant (cyanine) limit. The regimes differ by the presence or absence of twist-dependent polarization reversal and the occurrence of conical intersections. We find that selective biasing of one twisting channel over another by an applied diabatic biasing potential can only be achieved in a finite range of parameters near the cyanine limit.

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Section: Excited-state Driving Forces and Channel-specific Excitedmentioning

confidence: 95%

A two-state model of twisted intramolecular charge-transfer in monomethine dyes

Olsen

McKenzie

2012

The Journal of Chemical Physics

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“…This happens to be just under half of the experimentally measured transition dipole moment for Michler's hydrol blue 78 . The agreement in estimates of the rotor size is satisfying, since one is estimated from a hydrodynamic model of the non-radiative decay time 79 , while the other is obtained from an absorbance spectroscopy experiment 78 .…”

Section: Dye-solvent Interactionmentioning

confidence: 85%

Valence-bond non-equilibrium solvation model for a twisting monomethine cyanine

McConnell

McKenzie

Olsen

2015

The Journal of Chemical Physics

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We propose and analyze a two-state valence-bond model of non-equilibrium solvation effects on the excited-state twisting reaction of monomethine cyanines. Suppression of this reaction is thought responsible for environment-dependent fluorescence yield enhancement in these dyes. Fluorescence is quenched because twisting is accompanied via the formation of dark twisted intramolecular charge-transfer (TICT) states. For monomethine cyanines, where the ground state is a superposition of structures with different bond and charge localization, there are two possible twisting pathways with different charge localization in the excited state. For parameters corresponding to symmetric monomethines, the model predicts two low-energy twisting channels on the excited-state surface that lead to a manifold of twisted intramolecular charge-transfer (TICT) states. For typical monomethines, twisting on the excited state surface will occur with a small barrier or no barrier. Changes in the solvation configuration can differentially stabilize TICT states in channels corresponding to different bonds, and that the position of a conical intersection between adiabatic states moves in response to solvation to stabilize either one channel or the other. There is a conical intersection seam that grows along the bottom of the excited-state potential with increasing solvent polarity. For monomethine cyanines with modest-sized terminal groups in moderately polar solution, the bottom of the excited-state potential surface is completely spanned by a conical intersection seam.

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“…Arrow shows the flow direction now this calibration can be used to estimate the local lubricant viscosity in an EHD contact. Note, due to ThT's quantum yield being independent of temperature [31] and pressure [30], the calibration coefficients A and B are only dependent on the lubricant chemistry.…”

Section: Novel Calibration Methods To Obtain the Fluorescence Lifetimementioning

confidence: 99%

“…An increase in ThT quantum yield of more than three orders of magnitude due to increased solvent viscosity has been observed [29], after which its quantum yield plateaus. ThT's insensitivity to pressure and temperature makes it ideal to be used as a viscosity sensor in tribological contacts [30,31]. The local viscosity of IGE-PAL is thus extracted by measurements of ThT fluorescence lifetime at various positions in an EHD contact in this work.…”

Section: Brief Overview Of Thtmentioning

confidence: 99%

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Quantitative Viscosity Mapping Using Fluorescence Lifetime Measurements

2016

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Lubricant viscosity is a key driver in both the tribological performance and energy efficiency of a lubricated contact. Elastohydrodynamic (EHD) lubrication produces very high pressures and shear rates, conditions hard to replicate using conventional rheometry. In situ rheological measurements within a typical contact are therefore important to investigate how a fluid behaves under such conditions. Molecular rotors provide such an opportunity to extract the local viscosity of a fluid under EHD lubrication. The validity of such an application is shown by comparing local viscosity measurements obtained using molecular rotors and fluorescence lifetime measurements, in a model EHD lubricant, with reference measurements using conventional rheometry techniques. The appropriateness of standard methods used in tribology for high-pressure rheometry (combining friction and film thickness measurements) has been verified when the flow of EHD lubricant is homogeneous and linear. A simple procedure for calibrating the fluorescence lifetime of molecular rotors at elevated pressure for viscosity measurements is proposed.

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Temperature Dependence of the Fluorescence Properties of Thioflavin-T in Propanol, a Glass-Forming Liquid

Cited by 40 publications

References 33 publications

A two-state model of twisted intramolecular charge-transfer in monomethine dyes

A two-state model of twisted intramolecular charge-transfer in monomethine dyes

Valence-bond non-equilibrium solvation model for a twisting monomethine cyanine

Quantitative Viscosity Mapping Using Fluorescence Lifetime Measurements

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