Dual fluorescence of donor-acceptor molecules and the Twisted Intramolecular Charge Transfer (TICT) states

Grabowski, Zbigniew R.; Rotkiewicz, Krystyna; Siemiarczuk, Aleksander

doi:10.1016/0022-2313(79)90153-4

Cited by 348 publications

(541 citation statements)

References 11 publications

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“…Several theoretical models have been proposed to describe spectral shifts accompanying changes in solvent polarity [26][27][28][29][30]. These shifts are either due to general solvent effects like changes in dipole moment or refractive index, or to specific solvent effects like hydrogen bonding or formation of internal charge transfer (ICT)/twisted internal charge transfer (TICT) states [31,32]. Dipole moment and refractive index show opposite effects on spectral shift.…”

Section: Effect Of Microenvironment On 2ap Lifetime Distributionmentioning

confidence: 99%

Fluorescence intensity decays of 2-aminopurine solutions: Lifetime distribution approach

Bharill

Sarkar

Ballin

et al. 2008

Analytical Biochemistry

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The fluorescent adenine analogue 2-aminopurine (2AP) has been used extensively to monitor conformational changes and macromolecular binding events involving nucleic acids because its fluorescence properties are highly sensitive to changes in chemical environment. Furthermore, site-specific incorporation of 2AP permits local DNA and RNA conformational events to be discriminated from the global structural changes monitored by UV/Vis spectroscopy and circular dichroism. However, while the steady-state fluorescence properties of 2AP have been well defined in diverse settings, interpretation of 2AP fluorescence lifetime parameters has been hampered by the heterogeneous nature of multi-exponential 2AP intensity decays observed across populations of microenvironments. To resolve this problem, we have tested the utility of multi-exponential versus continuous Lorentzian lifetime distribution models to describe fluorescence intensity decays from 2AP in diverse chemical backgrounds and within the context of RNA. Heterogeneity was introduced into 2AP intensity decays by mixing solvents of differing polarities, or by adding quenchers under high viscosity to evaluate the transient effect. Heterogeneity of 2AP fluorescence within the context of a synthetic RNA hairpin was introduced by structural remodeling using a magnesium salt. In each case, except folded RNA which required a bimodal distribution, 2AP lifetime properties were well described by single Lorentzian distribution functions, abrogating the need to introduce additional discrete lifetime subpopulations. Rather, heterogeneity in fluorescence decay processes was accommodated by the breadth of each distribution. This approach also permitted solvent relaxation effects on 2AP emission to be assessed by comparing lifetime distributions at multiple wavelengths. Together, these studies provide a new perspective for the interpretation of 2AP fluorescence lifetime properties, which will further the utility of this Publisher's Disclaimer: This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. HHS Public Access Author Manuscript Author ManuscriptAuthor ManuscriptAuthor Manuscript fluorophore in analyses of the complex and heterogeneous structural microenvironments associated with nucleic acids.

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Section: Effect Of Microenvironment On 2ap Lifetime Distributionmentioning

confidence: 99%

Fluorescence intensity decays of 2-aminopurine solutions: Lifetime distribution approach

Bharill

Sarkar

Ballin

et al. 2008

Analytical Biochemistry

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“…From the substituent and solvent dependence, this state was shown to be connected with the donor and acceptor properties of amine and coumarine moieties, and was assigned as a Twisted Intramolecular Charge Transfer (TICT) state (8) with the dialkylamino group twisted perpendicularly to the plane of the coumarine skeleton. By making this twisting motion unavailable through ring closure to the "rigidized structure" of Coumarine 102 or 153, the fluorescence quenching is suppressed (7).…”

Section: Introductionmentioning

confidence: 99%

Intramolecular fluorescence quenching in aminocoumarines. Identification of an excited state with full charge separation

Rettig¹,

Klock²

1985

Can. J. Chem.

102

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This paper is dedicated to Professor Camille Sandorb on the occasion of his 65th birthdayWOLFCAND REPIC and ANDRE KLOCK. Can. J. Chem. 63, 1649 (1985) The fluorescence of 6-aminocoumarine (A6C) is very weak and anomalously redshifted as compared to its 7-substituted analogues 4-methyl-7-aminocoumarine (A7C) and 4-methyl-7-diethylaminocoumarine (DEA7C). The solvatochromic redshift in homologous alcohols is much stronger for A6C, pointing to an increased dipole moment of the emitting state. A twisted intramolecular charge transfer (TICT) state with full charge separation is made responsible for this emission. This is rationalized by molecules-in-molecules calculations. The strong Stokes shift in n-hexane and in ethanol glass at 77 K suggests that A6C emits from a TICT state even under these conditions. WOLFCAND REPIC et ANDRE KLOCK. Can. J. Chem. 63, 1649 (1985). La fluorescence de l'amino-6 coumarine (A6C) est trks faible et elle glisse de faqon anormale vers le rouge si on fait une comparaison avec des composCs analogues substituCs en position-7 comme la methyl-4 amino-7 coumarine (A7C) et la mCthyl-4 diCthylamino-7 coumarine (DEA7C). Le glissement solvatochrome vers le rouge provoqut par les alcools homologues est plus prononct avec le A6C et ceci suggkre qu'il y a une augmentation du moment dipolaire de 1'Ctat qui Cmet. On attribue cette Cmission a un Ctat de transfert de charge intramolCculaire croist (TCIC) avec une sCparation complkte de charges.On rationalise ce fait en fonction des calculs sur des molCcules dans des moltcules. Le fort glissement de Stokes dans le n-hexane et dans 1'Cthanol a 77 K suggkre que, mCme dans ces conditions, le A6C Cmet partir de I'etat TCIC.[Traduit par le journal] Introduction Lippert and co-workers (1-5) observed several types of adiabatic and diabatic photoreactions in dilute solutions of 7-hydroxycoumarine and related compounds as revealed from multiple fluorescence spectra.Only those coumarine dyes which possess an electron donor substituent in the 7 position showed a rather high and tunable LASER efficiency, whereas donor substitution in the 6 position strongly reduces the fluorescence quantum yield. Even some 7-dialkylamino coumarines are prone to undergo fluorescence quenching in polar solvents. This has been traced back by Jones, Halpern et al. (6,7) to an adiabatic photoreaction towards a nonemissive state.From the substituent and solvent dependence, this state was shown to be connected with the donor and acceptor properties of amine and coumarine moieties, and was assigned as a Twisted Intramolecular Charge Transfer (TICT) state (8) with the dialkylamino group twisted perpendicularly to the plane of the coumarine skeleton. By making this twisting motion unavailable through ring closure to the "rigidized structure" of Coumarine 102 or 153, the fluorescence quenching is suppressed (7). For the same reason, "rigidized" rhodamines show an enhanced fluorescence quantum yield at room temperature as compared to the nonrigidized strctures (rhodamine B vs. rhodamine 10 1 (9...

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“…The experimental probe of the ICT-state geometry has been made by studying fluorescence of covalently modified DMABN in which the electron-donor moiety ͑viz., dimethylamino group͒ is fixed to lie either parallel or perpendicular to the plane of the electron-acceptor moiety ͑viz., benzonitrile͒. These studies have established that the most likely geometry of the ICT state of DMABN is the so-called twisted ICT ͑TICT͒ state 3,4 in which the positively charged dimethylamino group is twisted with respect to the plane of the negatively charged benzonitrile moiety. The twisted geometry minimizes the Coulombic interaction between the unpaired electrons with consequent stabilization of the ICT state.…”

mentioning

confidence: 99%

Do fluorescence and transient absorption probe the same intramolecular charge transfer state of 4-(dimethylamino)benzonitrile?

Gustavsson

Coto

Serrano‐Andrés

et al. 2009

The Journal of Chemical Physics

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Dual fluorescence of donor-acceptor molecules and the Twisted Intramolecular Charge Transfer (TICT) states

Cited by 348 publications

References 11 publications

Fluorescence intensity decays of 2-aminopurine solutions: Lifetime distribution approach

Fluorescence intensity decays of 2-aminopurine solutions: Lifetime distribution approach

Intramolecular fluorescence quenching in aminocoumarines. Identification of an excited state with full charge separation

Do fluorescence and transient absorption probe the same intramolecular charge transfer state of 4-(dimethylamino)benzonitrile?

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