Femtosecond study of S2 fluorescence in malachite green in solutions

Yoshizawa, M.; Suzuki, Kazuya; Kubo, Atsushi; Saikan, S.

doi:10.1016/s0009-2614(98)00483-7

Cited by 61 publications

(78 citation statements)

References 15 publications

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“…This behavior points towards af luorescencec ontribution from a higher lying excited state rather than solely from the S 1 state, a process that could also be disclosed in time-resolved fluorescence studies for variouso rganic molecules. [49][50][51][52][53][54] Note that the relative ratio of the two PTC emission spectra of Figure 1b at the maximum wavelength is 0.20, which basically matches the absorbance ratio at 267 and 350 nm, which is derived as 0.16 from Figure 1a.…”

Section: Steady-state Spectroscopysupporting

confidence: 72%

Ultrafast Dynamics of a Fluorescent Tetrazolium Compound in Solution

et al. 2017

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Tetrazolium salts are exploited in various fields of research by virtue of their low reduction potentials. Increasingly, associated applications also attend to the photochemical and luminescence properties of these systems. Here, we investigate the photoinduced dynamics of phenyl-benzo[c]tetrazolo-cinnolinium chloride (PTC), one of the very few known fluorescent tetrazolium compounds, by using time-correlated single-photon counting, femtosecond fluorescence upconversion, and ultrafast transient absorption spectroscopy. PTC is generated photochemically by ultraviolet illumination of 2,3,5-triphenyl-tetrazolium chloride (TTC) in various alcohols. Time-resolved fluorescence measurements on PTC with different excitation wavelengths disclose biphasic solvation and vibrational relaxation dynamics. Depending on the solvent, the emission behavior of PTC is characterized by quantum yields on the order of several tens of percent and corresponding excited-state lifetimes of several hundreds of picoseconds. The radiative rate is basically constant for the studied alcohols, whereas the rate of the competing non-radiative process is sensitive to the solvent polarity. Hence, we discuss the possible involvement of intermediate radicals and further presumptive reaction pathways pursued after photoexcitation of PTC.

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Section: Steady-state Spectroscopysupporting

confidence: 72%

Ultrafast Dynamics of a Fluorescent Tetrazolium Compound in Solution

et al. 2017

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“…The peaks at 425 and 617 nm are due to splitting of the excited state in the low symmetry of MG, 17 assigned as the S 2 and S 1 states, respectively. 30 The shoulder at 570 nm may come from an isomer of MG. 24 Reduction of MG and of the dimethylani-line converts MG into LMG. LMG exhibits a completely different UV/vis spectrum, as shown in Figure 2A (blue line): the two peaks at 425 and 617 nm disappear.…”

Section: Resultsmentioning

confidence: 99%

Direct Observation and Control of Ultrafast Photoinduced Twisted Intramolecular Charge Transfer (TICT) in Triphenyl-Methane Dyes

Magana

Dyer

2012

J. Phys. Chem. B

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Femtosecond time-resolved infrared spectroscopy was employed to study intramolecular charge transfer in triphenylmethane dyes, including malachite green (MG), malachite green carbinol base (MGCB), and leucomalachite green (LMG). A local excited state (LE) and a twisted intramolecular charge-transfer (TICT) state have been observed directly in MG. Furthermore, solvent-controlled TICT measurements in a series of linear alcohols indicate that the transition time (4–11 ps) from LE to TICT is strongly dependent on alcohol viscosity, which is due to rotational hindrance of dimethylaniline in high-viscosity solvents. For LMG, no TICT is observed due to steric hindrance caused by the sp3-hybridized central carbon atom. However, for MGCB, TICT is rescued by the addition of the electron-donating hydroxyl group to the bridge. These results for MG and its analogues provide new insight regarding the dynamics and mechanism of twisted intramolecular charge transfer (TICT) in triphenylmethane dyes.

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“…68 In the monomethine dye malachite green, the S 2 state can be accessed by both one-and two-photon excitations, and emission can be detected from both states. 70,71 Decay to the S 1 state occurs on ultrafast timescales and the dynamics suggest torsional motion may be involved. Ab initio models of photoactive yellow protein chromophores suggest that S 2 / S 1 intersections may directly 66 or indirectly 72 affect the photophysics of these systems.…”

Section: Discussionmentioning

confidence: 99%

Conical Intersections, charge localization, and photoisomerization pathway selection in a minimal model of a degenerate monomethine dye

Olsen

McKenzie

2009

The Journal of Chemical Physics

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We propose a minimal model Hamiltonian for the electronic structure of a monomethine dye, in order to describe the photoisomerization of such dyes. The model describes interactions between three diabatic electronic states, each of which can be associated with a valence bond structure. Monomethine dyes are characterized by a charge-transfer resonance; the indeterminacy of the single-double bonding structure dictated by the resonance is reflected in a duality of photoisomerization pathways corresponding to the different methine bonds. The possible multiplicity of decay channels complicates mechanistic models of the effect of the environment on fluorescent quantum yields, as well as coherent control strategies. We examine the extent and topology of intersection seams between the electronic states of the dye and how they relate to charge localization and selection between different decay pathways. We find that intersections between the S(1) and S(0) surfaces only occur for large twist angles. In contrast, S(2)/S(1) intersections can occur near the Franck-Condon region. When the molecule has left-right symmetry, all intersections are associated with con- or disrotations and never with single bond twists. For asymmetric molecules (i.e., where the bridge couples more strongly to one end) the S(2) and S(1) surfaces bias torsion about different bonds. Charge localization and torsion pathway biasing are correlated. We relate our observations with several recent experimental and theoretical results, which have been obtained for dyes with similar structure.

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Femtosecond study of S2 fluorescence in malachite green in solutions

Cited by 61 publications

References 15 publications

Ultrafast Dynamics of a Fluorescent Tetrazolium Compound in Solution

Ultrafast Dynamics of a Fluorescent Tetrazolium Compound in Solution

Direct Observation and Control of Ultrafast Photoinduced Twisted Intramolecular Charge Transfer (TICT) in Triphenyl-Methane Dyes

Conical Intersections, charge localization, and photoisomerization pathway selection in a minimal model of a degenerate monomethine dye

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