Early Excited State Dynamics of 6-Styryl-Substituted Pyrylium Salts Exhibiting Dual Fluorescence

Pigliucci, Anatolio; Nikolov, P.; Rehaman, Abdul; Gagliardi, Laura; Cramer, Christopher J.; Vauthey, Eric

doi:10.1021/jp063214x

Cited by 27 publications

(31 citation statements)

References 60 publications

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“…[44,45] Therefore, this Gaussian component can be possibly associated with vibrational relaxation processes taking place from the initially Franck- Condon region of the excited state down to the equilibrium. [46,47] A Gaussian component was also found in all the other systems investigated herein. As its width, t 1 , and the wavelength dependence of its amplitude is essentially the same for all these systems, this component is not discussed further.…”

Section: Ultrafast Fluorescence Dynamicssupporting

confidence: 61%

Site‐Dependent Excited‐State Dynamics of a Fluorescent Probe Bound to Avidin and Streptavidin

et al. 2009

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Sensing protein environment: The femtosecond fluorescence dynamics of a molecular probe attached to avidin and streptavidin (see figure) depends markedly on the location of the probe and on the protein. These differences reflect not only the protein primary and tertiary structures but also the effect of the surrounding water molecules. The excited‐state dynamics of biotin–spacer–Lucifer‐Yellow (LY) constructs bound to avidin (Avi) and streptavidin (Sav) was investigated using femtosecond spectroscopy. Two different locations in the proteins, identified by molecular dynamics simulations of Sav, namely the entrance of the binding pocket and the protein surface, were probed by varying the length of the spacer. A reduction of the excited‐state lifetime, stronger in Sav than in Avi, was observed with the long spacer construct. Transient absorption measurements show that this effect originates from an electron transfer quenching of LY, most probably by a nearby tryptophan residue. The local environment of the LY chromophore could be probed by measuring the time‐dependent polarisation anisotropy and Stokes shift of the fluorescence. Substantial differences in both dynamics were observed. The fluorescence anisotropy decays analysed by using the wobbling‐in‐a‐cone model reveal a much more constrained environment of the chromophore with the short spacer. Moreover, the dynamic Stokes shift is multiphasic in all cases, with a ∼1 ps component that can be ascribed to diffusive motion of bulk‐like water molecules, and with slower components with time constants varying not only with the spacer, but with the protein as well. These slow components, which depend strongly on the local environment of the probe, are ascribed to the motion of the hydration layer coupled to the conformational dynamics of the protein.

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Section: Ultrafast Fluorescence Dynamicssupporting

confidence: 61%

Site‐Dependent Excited‐State Dynamics of a Fluorescent Probe Bound to Avidin and Streptavidin

et al. 2009

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“…[28][29][30][31][32] Results and discussion Table 1). The ultrafast fluorescence measurements (and the time resolved area normalised emission spectra analysis in particular) indeed allowed us to identify the presence of two distinct emitting species, characterised by similar emission energies, and to distinguish their population dynamics from simple relaxation processes, such as solvation.…”

Section: Introductionmentioning

confidence: 97%

An ultrafast spectroscopic and quantum mechanical investigation of multiple emissions in push–pull pyridinium derivatives bearing different electron donors

Carlotti

Benassi

Cesaretti

et al. 2015

Phys. Chem. Chem. Phys.

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A joint experimental and theoretical approach, involving state-of-the-art femtosecond fluorescence up-conversion measurements and quantum mechanical computations including vibronic effects, was employed to get a deep insight into the excited state dynamics of two cationic dipolar chromophores (Donor-π-Acceptor(+)) where the electron deficient portion is a N-methyl pyridinium and the electron donor a trimethoxyphenyl or a pyrene, respectively. The ultrafast spectroscopic investigation, and the time resolved area normalised emission spectra in particular, revealed a peculiar multiple emissive behaviour and allowed the distinct emitting states to be remarkably distinguished from solvation dynamics, occurring in water in a similar timescale. The two and three emissions experimentally detected for the trimethoxyphenyl and pyrene derivatives, respectively, were associated with specific local emissive minima in the potential energy surface of S1 on the ground of quantum-mechanical calculations. A low polar and planar Locally Excited (LE) state together with a highly polar and Twisted Intramolecular Charge Transfer (TICT) state is identified to be responsible for the dual emission of the trimethoxyphenyl compound. Interestingly, the more complex photobehaviour of the pyrenyl derivative was explained considering the contribution to the fluorescence coming not only from the LE and TICT states but also from a nearly Planar Intramolecular Charge Transfer (PICT) state, with both the TICT and the PICT generated from LE by progressive torsion around the quasi-single bond between the methylpyridinium and the ethene bridge. These findings point to an interconversion between rotamers for the pyrene compound taking place in its excited state against the Non-equilibrated Excited Rotamers (NEER) principle.

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“…To verify the presence of two orthogonal transitions in ARh, we developed a methodology to fit the observed fluorescence anisotropy. The conclusion is that ARh contains two chromophores with properties similar to that of an arylpyrylium dye47–55 and a rhodamine dye,3, 4 respectively. In the two chromophores, the distinct excited states couple weakly despite an energy spacing of only approximately 1000 cm −1 .…”

Section: Introductionmentioning

confidence: 99%

Aminorhodamine (ARh): A Bichromophore with Three Emission Bands in Low Temperature Glasses

Sørensen

Kilså

Laursen

2015

Chemistry A European J

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At first glance, aminorhodamine (ARh) is a typical pH responsive fluorescent, rhodamine-type dye. However, hidden under the typical rhodamine absorption band, ARh has another electronic transition of similar energy, but polarized orthogonal to that of the rhodamine chromophore. This transition-assigned to an arylpyrylium type chromophore contained in the system-is responsible for the sensor action of the dye. ARh is non-fluorescent, while protonation of a donor amino group turn on a strong rhodamine-type emission. At low temperature in frozen solution emission from both electronic subsystems of ARh are observed. In order to achieve more complete understanding of the photophysical mechanisms in this type of fluorescent probes, ARh and its protonated counterpart HARh were studied by absorption and fluorescence spectroscopy, computational chemistry, and at low temperatures in solid solution. Results from fluorescence anisotropy and time-resolved fluorescence spectra establish a bichromophore model and suggest that a remarkable weak coupling between the two nearly isoenergetic excited states in ARh enables the dual emission. All the complicated properties observed for ARh was accounted for by a bichromophore model describing the electronic system of ARh as a bichromophore constituted by a rhodamine and an arylpyrylium subsystem.

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Early Excited State Dynamics of 6-Styryl-Substituted Pyrylium Salts Exhibiting Dual Fluorescence

Cited by 27 publications

References 60 publications

Site‐Dependent Excited‐State Dynamics of a Fluorescent Probe Bound to Avidin and Streptavidin

Site‐Dependent Excited‐State Dynamics of a Fluorescent Probe Bound to Avidin and Streptavidin

An ultrafast spectroscopic and quantum mechanical investigation of multiple emissions in push–pull pyridinium derivatives bearing different electron donors

Aminorhodamine (ARh): A Bichromophore with Three Emission Bands in Low Temperature Glasses

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