Excited-state dynamics and viscosity-dependent internal conversion in 3,3-dimethyl-2-phenyl-3H-indole

Belletête, Michel; Sarpal, Ranjit S.; Durocher, Gilles

doi:10.1016/0009-2614(93)85048-s

Cited by 30 publications

(27 citation statements)

References 34 publications

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“…Table 2 shows that the knr values of these molecules in n-heptane also decrease with a decrease in the fluorescence transition energy and a concomitant increase in the electronic delocalization throughout the molecule. This supports the assumption that the main radiationless deactivation pathway is the motion of the Phc ring (14)(15)(16)(17)22). As the electronic delocalization increases, themolecule becomes less flexible, consequently k,, is reduced.…”

Section: Neutral Speciessupporting

confidence: 80%

“…In the present set of molecules, it is well-known that the lowest energy transition is of the .rr.rr* type is polarized along the long molecular axis (14)(15)(16)(17)22). Table 1 shows that the energy of the absorption spectrum of these molecules in n-heptane decreases from 1 to 3 and from 4 to 6.…”

Section: Neutral Speciesmentioning

confidence: 71%

“…Changes in the spectral shifts have been used to evaluate the dipole moments of the ground and first singlet excited states, which compared favorably with the results of INDO-S calculations (15). The first excited singlet state is more polar by a factor of two in all cases studied (16,17). AMPAC and INDO-S calculations have also shown that the phenyl moiety is not coplanar with the rest of the molecule and is allowed to librate within the kT energy barrier.…”

Section: Since Natural Photosynthesis Involves Charge Separation On Amentioning

confidence: 93%

“…We have shown recently that these molecules are not rigid and that the phenyl ring can librate to a certain extent within the kT energy barrier (14)(15)(16)(17)22). The freedom of this motion should be reduced when the electronic delocalization throughout the molecule is increased.…”

Section: Neutral Speciesmentioning

confidence: 99%

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Photophysics of some substituted 3H-indole probe molecules and their charged species

Belletête¹,

Sarpal²,

Durocher³

1994

Can. J. Chem.

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The spectroscopic and photophysical parameters of neutral and cationic species of the following molecules have been discussed: 2-phenyl-3,3-dimethyl-3H-indole (1). 2-[@-amino)phenyl]-3.3-dimethyl-3H-indole (2), 2-[QI-dimethylamino)phenyl]-3,3-dimethyl-3H-indole (3), 2-[@-amino)phenyl]-3,3-dimethyl-5-carboethoxy-3H-indole (4). 2-[@-methylamino)phenyl]-3,3-dimethyl-5-carboethoxy-3H-indole (5),2-[@-dimethylamino)phenyl]-3,3-dimethyl-5-carb0eth0xy-3H-ind0le (6). Solvatochromic shifts have been interpreted in terms of the nature of the substituent groups and the state of solute-solvent interactions and complexation. The theoretical radiative decay rate constant (kt;) along with the bandwidth of the absorption profile of the different species involved have been used to discuss the geometrical changes from one species to the other in the ground state. The mirror-image relationship between absorption and fluorescence spectra has proven to be a good tool to discuss any geometrical changes occuning in the excited state. A radiationless torsional mechanism takes place in the excited state relaxation of the various species. The protonation of the ring nitrogen atom generates a highly planar cationic species which retains its conformation in the relaxed excited state. The very effective quenching of the monocation fluorescence is interpreted by the formation of a non-emissive TICT state.MICHEL BELLE~TE, RANIIT S. SARPAL et GILLES DUROCHER'. Can. J. Chem. 72,2239Chem. 72, (1994. On discute des paramktres spectroscopiques et photophysiques des espkces neutres et cationiques suivantes: 2-phCnyl-3,3-dimtthyl-3H-indole (I), 2-[@-amino)phCnyl]-3,3-dimCthyl-3H-indole (2), 2-[(p-dimtthylamino)phtnyl]-3,3-dimtthyl-3H-indole (3), 2-[@-amino)phtnyl]-3,3-dimtthyl-5-carboCthoxy-3H-indole (4), 2-[@-mCthylamino)phCnyl]-3,3-dimethyl-5-carbotthoxy-3H-indole (5) et 2-[@-dimtthylamino)phCnyl]-3,3-dimCthyl-3H-indole (6).On interprkte les dCplacements solvatochromiques en fonction de la nature des substituants et de 1'Ctat des interactions et de la complexation solut6solvant. On a utilisC les constantes thCoriques de vitesse de la dCgCnCrescence radiative (kt;) de concert avec la largeur de bande du profile d'absorption des difftrentes espkces impliqutes pour discuter des changements de gtomCtrie se produisant d'une espkce B l'autre dans l'ttat fondamental. On a prouvC que la relation d'image dans un miroir entre les spectres d'absorption et de fluorescence est un bon outil pour discuter de tout changement gComCtrique se produisant dans 1'Ctat excitt. Un mecanisme de torsion sans radiation se produit dans la relaxation de 1'Ctat excitC des diverses espkces. La protonation de l'atome d'azote dy cycle gtnkre une espkce cationique trks plane qui retient sa conformation dans I'Ctat excitC relaxt. On interprkte la dtsactivation trks efficace de la fluorescence du monocation par la formation d'un Ctat TICT qui ne donne pas d'Cmission.[Traduit par la rCdaction]

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Section: Neutral Speciessupporting

confidence: 80%

Section: Neutral Speciesmentioning

confidence: 71%

Section: Since Natural Photosynthesis Involves Charge Separation On Amentioning

confidence: 93%

Section: Neutral Speciesmentioning

confidence: 99%

See 2 more Smart Citations

Photophysics of some substituted 3H-indole probe molecules and their charged species

Belletête¹,

Sarpal²,

Durocher³

1994

Can. J. Chem.

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“…[17][18][19][20][21][22][23][24][25][26][27] So far, we have probed successfully the mean structural properties of aqueous micelles, 23,24,26 reversed micelles, 25 and surfactant vesicles. 27 Very recently, we started a research program on the formation of inclusion complexes between cyclodextrins and some 3H-indoles, i.e., 2-(p-aminophenyl)-3,3-dimethyl-5-carboethoxy-3H-indole (2), 28 2-(p-methylaminophenyl)-3,3-dimethyl-5-carboethoxy-3H-indole (3), 29 2-(p-dimethylaminophenyl)-3,3-dimethyl-5-carboethoxy-3H-indole (4), 28 2-(p-aminophenyl)-3,3-dimethyl-5-cyano-3H-indole (5), 30,31 and 2-(p-dimethylaminophenyl)-3,3-dimethyl-5-cyano-3H-indole (6).…”

Section: Introductionmentioning

confidence: 99%

Spectral and Photophysical Studies of the 1:3 (Guest/Host) Rotaxane-like Inclusion Complex Formed by a 3H-Indole and β-Cyclodextrin

1998

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In the present paper, we report a new type of rotaxane-like inclusion complex, i.e., the 1:3 (guest/host) type formed by iodotrimethyl 2-(p-hexylaminophenyl)-3,3-dimethyl-5-carboethoxy-3H-indole ammonium (1), a fluorescent cationic surfactant, and -cyclodextrin ( -CD). The time-resolved fluorescence measurement reveals that only two species of 1 exist within the whole range of -CD concentrations. Both the steadystate and the time-resolved fluorescence results show that the stoichiometry of the inclusion complex is 1:3. The urea effect on the formation of the inclusion complex has been investigated. It was found that the 1:3 inclusion complex is still formed in the presence of 3 M urea, while the association constant is markedly reduced. This suggests the hydrophobic nature of the interaction of 1 with either -CD or urea.

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Fluorimetric Cell Analysis with 9‐Aryl‐Substituted Berberine Derivatives as DNA‐Targeting Fluorescent Probes

Groß,

Hoffmann,

Müller

et al. 2023

ChemBioChem

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DNA‐sensitive fluorescent light‐up probes based on berberine are presented. This biogenic fluorophore was chosen as central unit to use its potential biocompatibility and its DNA‐binding properties. To provide predictable fluorescence quenching in aqueous solution and a fluorescence light‐up effect upon DNA binding, aryl substituents were attached at the 9‐position by Suzuki‐Miyaura coupling reactions. The 9‐arylberberine derivatives have a very low fluorescence quantum yield (Φfl=<0.02), which is caused by the radiationless deactivation of the excited state by torsional relaxation about the biaryl axis. In addition, these berberine derivatives intercalate into DNA with high affinity (Kb=2.0−22×104 M−1). Except for the nitrophenyl‐ and hydroxyphenyl‐substituted derivatives, all tested compounds exhibited a pronounced fluorescence light‐up effect upon association with DNA, because the deactivation of the excited‐state by torsional relaxation is suppressed in the DNA binding site. Most notably, it was shown exemplarily with the 9‐(4‐methoxyphenyl)‐ and the 9‐(6‐methoxynaphthyl)‐substituted derivatives that these properties are suited for fluorimetric cell analysis. In particular, these probes generated distinct staining patterns in eukaryotic cells (NIH 3T3 mouse fibroblasts), which enabled the identification of nuclear substructures, most likely heterochromatin or nucleoli, respectively.

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Excited-state dynamics and viscosity-dependent internal conversion in 3,3-dimethyl-2-phenyl-3H-indole

Cited by 30 publications

References 34 publications

Photophysics of some substituted 3H-indole probe molecules and their charged species

Photophysics of some substituted 3H-indole probe molecules and their charged species

Spectral and Photophysical Studies of the 1:3 (Guest/Host) Rotaxane-like Inclusion Complex Formed by a 3H-Indole and β-Cyclodextrin

Fluorimetric Cell Analysis with 9‐Aryl‐Substituted Berberine Derivatives as DNA‐Targeting Fluorescent Probes

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