Ultrafast internal charge transfer in a donor-modified rhodamine

Plaza, Pascal; Hung, Nguyen Ba; Martin, Monique M.; Meyer, Yves; Vögel, Martin; Rettig, Wolfgang

doi:10.1016/0301-0104(92)87170-e

Cited by 33 publications

(47 citation statements)

References 13 publications

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“…Slowing down of conformational motions by binding attachments or by forming double molecules leads to the similar behavior. Similar effect of the lower sensitivity of the ''dark" state relaxation rate as compared with its formation rate to the solvent viscosity has also been observed for auramine [29] and ethyl violet [30]. The straight forward explanation is that the ''dark" state formation rate is limited by the molecule twisting, while its relaxation is limited by the internal conversion in the twisted state.…”

Section: Discussionsupporting

confidence: 57%

“…These flat in the ground state molecules have several torsional degrees of freedom, and twisting of one or simultaneously several bonds may take place in the excited state. Generally, bond twisting in the excited state leads to the fast nonradiative relaxation [5][6][7][8][9], with occasional formation of nonemissive ''dark" states [10][11][12], or to the appearance of the dual fluorescence bands [13][14][15][16][17][18][19][20][21][22][23]. The dual fluorescence is a well known signature of the intramolecular charge transfer in 4-(dimethylamino)benzonitrile (DMABN) class molecules, which form twisted internal charge transfer (TICT) states involving the twisting of the amino group [14].…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Multicoordinational excited state twisting of indan-1,3-dione derivatives

Karpicz¹,

Getautis

Kazlauskas³

et al. 2008

Chemical Physics

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Section: Discussionsupporting

confidence: 57%

Section: Introductionmentioning

confidence: 99%

Multicoordinational excited state twisting of indan-1,3-dione derivatives

Karpicz¹,

Getautis

Kazlauskas³

et al. 2008

Chemical Physics

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“…If the dialkylanilino group is protonated and transformed into a weak acceptor, the quenching channel is blocked, and the quantum yield increases by a factor of 290. [53] This mechanism is closely related to the TICT theory of excited states in which CT and twisting are combined and the maximum CT is observed for the perpendicular conformation. In some cases, dual fluorescence can arise, whereas, in other cases, only the fluorescence quenching of the precursor state is observed; this could be induced by the relaxation of the pending donor group towards the perpendicular conformation.…”

Section: Quantum Chemical Calculationsmentioning

confidence: 86%

Optical, Redox, and DNA‐Binding Properties of Phenanthridinium Chromophores: Elucidating the Role of the Phenyl Substituent for Fluorescence Enhancement of Ethidium in the Presence of DNA

Prunkl

Pichlmaier

Winter

et al. 2010

Chemistry A European J

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The phenanthridinium chromophores 5-ethyl-6-phenylphenanthridinium (1), 5-ethyl-6-methylphenanthridinium (2), 3,8-diamino-5-ethyl-6-methylphenanthridinium (3), and 3,8-diamino-5-ethyl-6-(4-N,N-diethylaminophenyl)phenanthridinium (4) were characterized by their optical and redox properties. All dyes were applied in titration experiments with a random-sequence 17mer DNA duplex and their binding affinities were determined. The results were compared to well-known ethidium bromide (E). In general, this set of data allows the influence of substituents in positions 3, 6, and 8 on the optical properties of E to be elucidated. Especially, compound 4 was used to compare the weak electron-donating character of the phenyl substituent at position 6 of E with the more electron-donating 4-N,N-diethylaminophenyl group. Analysis of all of the measurements revealed two pairs of chromophores. The first pair, consisting of 1 and 2, lacks the amino groups in positions 3 and 8, and, as a result, these dyes exhibit clearly altered optical and electrochemical properties compared with E. In the presence of DNA, a significant fluorescence quenching was observed. Their binding affinity to DNA is reduced by nearly one order of magnitude. The electronic effect of the phenyl group in position 6 on this type of dye is rather small. The properties of the second set, 3 and 4, are similar to E due to the presence of the two strongly electron-donating amino groups in positions 3 and 8. However, in contrast to 1 and 2, the electron-donating character of the substituent in position 6 of 3 and 4 is critical. The binding, as well as the fluorescence enhancement, is clearly related to the electron-donating effect of this substituent. Accordingly, compound 4 shows the strongest binding affinity and the strongest fluorescence enhancement. Quantum chemical calculations reveal a general mechanism related to the twisted intramolecular charge transfer (TICT) model. Accordingly, an increase of the twist angle between the phenyl ring in position 6 and the phenanthridinium core opens a nonradiative channel in the excited state that depends on the electron-donating character of the phenyl group. Access to this channel is hindered upon binding to DNA.

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“…One simple donor‐substituted rhodamine derivative, aminorhodamine (ARh, Figure 1), previously studied by Plaza and Martin,41, 42 has been assigned as non‐fluorescent due to quenching by the additional dialkylamino donor group on the pendant aryl ring system. The electron‐rich aromatic system can partake in an internal charge transfer, effectively dissipating the excited state energy and efficiently turning off the fluorescence of ARh.…”

Section: Introductionmentioning

confidence: 99%

“…The electron‐rich aromatic system can partake in an internal charge transfer, effectively dissipating the excited state energy and efficiently turning off the fluorescence of ARh. As a consequence, a fast non‐radiative decay from the excited state is experimentally observed in place of the high fluorescence quantum yield emission observed for rhodamines without the donor substituent 41. 42 If the donor group—nominally an aniline—is protonated, the fluorescent is turned on, and ARh may in this way act as a pH probe.…”

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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Ultrafast internal charge transfer in a donor-modified rhodamine

Cited by 33 publications

References 13 publications

Multicoordinational excited state twisting of indan-1,3-dione derivatives

Multicoordinational excited state twisting of indan-1,3-dione derivatives

Optical, Redox, and DNA‐Binding Properties of Phenanthridinium Chromophores: Elucidating the Role of the Phenyl Substituent for Fluorescence Enhancement of Ethidium in the Presence of DNA

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

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