Radiationless Transitions in Substituted Benzopyrylium Dyes: Competing Adiabatic Photoreactions Towards Nonradiative Funnels

Haucke, G.; Czerney, Peter; Steen, Dorika; Rettig, Wolfgang; Hartmann, Horst

doi:10.1002/bbpc.19930970405

Cited by 22 publications

(12 citation statements)

References 36 publications

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“…Recently, several cases of pyridinium, pyrylium, and benzopyrylium systems bearing no amino nitrogen have been investigated which show either polar solvent-enhanced fluorescence quenching or large Stokes' shifts, or even dual fluorescence. − In the case of the benzopyrylium salts, bridged model compounds have clearly established the involvement of a rotation mechanism. While the fluorescence quantum yield of the flexible compound 244 is only 0.007 in butyronitrile, is rises to 1.0 for the bridged compound 245 . If the donor system is biphenyl or phenanthrene, as in 246 and 247 , the large Stokes' shifts observed at room temperature, which are absent at 77 K, point to the possibility of strongly emitting charge-shift states.…”

Section: Ionic Dye Systems Not Involving Amino Groupsmentioning

confidence: 99%

Structural Changes Accompanying Intramolecular Electron Transfer: Focus on Twisted Intramolecular Charge-Transfer States and Structures

2003

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Section: Ionic Dye Systems Not Involving Amino Groupsmentioning

confidence: 99%

Structural Changes Accompanying Intramolecular Electron Transfer: Focus on Twisted Intramolecular Charge-Transfer States and Structures

2003

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“…(1.0 AE 0.9) Â 10 À4 (7.9 AE 0.9) Â 10 À5 to a wider class of chalcone compounds, which are known to undergo complex photophysical and photochemical pathways, [145][146][147][148][149] where the photoisomerisation step has to compete with other processes taking place during the excited state lifetime. The deactivation pathways proposed for trans-chalcones are summarised in Scheme 30.…”

Section: Cis-trans Photoisomerisationmentioning

confidence: 99%

Chemistry and applications of flavylium compounds: a handful of colours

et al. 2012

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Flavylium compounds are versatile molecules that comprise anthocyanins, the ubiquitous colorants used by Nature to confer colour to most flowers and fruits. They have found a wide range of applications in human technology, from the millenary colour paints described by the Roman architect Vitruvius, to their use as food additives, combining colour and antioxidant effects, and even as light absorbers in solar cells aiming at a greener solar energy conversion. Their rich complexity derives in part from their ability to switch between a variety of species (flavylium cations, neutral quinoidal bases, hemiketals and chalcones, and negatively charged phenolates) by means of external stimuli, such as pH, temperature and light. This critical review describes (i) the historical advancements in the understanding of the equilibria of their chemical reaction networks; (ii) their thermodynamics and kinetics; (iii) the mechanisms underlying their colour development, such as co-pigmentation and host-guest interactions; (iv) the photophysics and photochemistry that lead to photochromism; and (v) applications in solar cells, models for optical memories, photochromic soft materials such as ionic liquids and gels, and their properties in solid state materials (274 references).

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“…Their fluorescence strongly depends on the substituents in the 2-phenyl-1-benzopyrylium core. In particular, the presence of amino groups decreases the fluorescence quantum yield in polar solvents apparently due to deactivation of the emissive excited state via internal charge transfer states [24]. Thus, it is expected that the interaction of flavylium cations with nucleic acids increases their fluorescence, leading these compounds as off-on fluorescent probes for nucleic acid detection.…”

Section: Introductionmentioning

confidence: 99%

Flavylium Dye as pH-Tunable Fluorescent and CD Probe for Double-Stranded DNA and RNA

et al. 2020

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The interaction of 4′-(N,N-dimethylamino)-6-hydroxyflavylium cation with double stranded (ds-) DNA/RNA was studied by UV/Vis spectrophotometry, circular dichroism (CD), and also steady-state and time-resolved emission spectroscopies at neutral and weakly acidic conditions. At pH 5, the studied molecule, in its flavylium cationic form, showed considerable binding affinities (5 < logKs < 6) for all ds-DNA/RNA, contrary to chalcones forms (dominant at pH 7), which did not show binding to polynucleotides. Flavylium cation intercalated into ds-DNAs at variance to dominant groove aggregation within ds-RNA, which was reported by RNA-specific bisignate induced CD spectrum (ICD) bands. The intrinsically negligible fluorescence of flavylium was strongly increased upon the addition of DNA or RNA, whereby both the fluorescence intensity and emission lifetimes of complexes differed considerably: the strongest emission increase was observed for AU-RNA (detection limit estimated to 10 nM) followed by AT-DNAs and the much weaker effect of GC-DNAs. Both fluorescence sensitivity on the ds-DNA/RNA secondary structure and sequence-selective ICD bands make the flavylium–chalcones system an intriguing pH-switchable new probe for distinguishing between various polynucleotide sequences.

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Radiationless Transitions in Substituted Benzopyrylium Dyes: Competing Adiabatic Photoreactions Towards Nonradiative Funnels

Cited by 22 publications

References 36 publications

Structural Changes Accompanying Intramolecular Electron Transfer: Focus on Twisted Intramolecular Charge-Transfer States and Structures

Structural Changes Accompanying Intramolecular Electron Transfer: Focus on Twisted Intramolecular Charge-Transfer States and Structures

Chemistry and applications of flavylium compounds: a handful of colours

Flavylium Dye as pH-Tunable Fluorescent and CD Probe for Double-Stranded DNA and RNA

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