Solvent induced changes in the electronic structure of a polar intermolecular exciplex

Orbach, N.; Ottolenghi, Michael

doi:10.1016/0009-2614(75)85309-7

Cited by 32 publications

(6 citation statements)

References 19 publications

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“…Spectroscopic evidence has been given for triplet exciplexes in nonpolar solvents,28 in polar solvents, however, their absorption spectra are not likely to be very different from the radical ion spectra. 29 From this point of view it would be of value to obtain some other means of probing triplet exciplexes in electron transfer reactions in polar solvents.…”

Section: Resultsmentioning

confidence: 99%

Investigation of physical triplet quenching by electron donors

Steiner¹,

Winter²,

Kramer³

1977

J. Phys. Chem.

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Absolute radical yields, as determined by flash spectroscopy, are reported for the reaction of the thionine triplet 3TH+ and its protonated form 3TH22+ with a variety of electron donors in methanolic solution. The yields are extrapolated to infinite donor concentrations. Two methods of obtaining absolute yields are described. The different yields with different donors are due to partial physical quenching of the triplets in the electron transfer reaction. The results are discussed in terms of different models, capable of explaining bimolecular intersystem crossing processes. A triplet exciplex as an intermediate in the electron transfer reaction is favored.

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Section: Resultsmentioning

confidence: 99%

Investigation of physical triplet quenching by electron donors

Steiner¹,

Winter²,

Kramer³

1977

J. Phys. Chem.

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“…Increased solvent polarity preferentially solvates and stabilises charge separation and at a dielectric constant of approximately 14 the pyrene:diethylaniline pair has an exciplex absorption spectrum identical with the ion pair, pyrene − :PhNEt 2 + . 23 Intramolecular exciplexes have recently been discovered which emit in solvents as polar as DMSO, propylene carbonate, or even 20% aqueous acetonitrile. 24 Intermolecular exciplex luminescence in polar: nonpolar solvent mixtures (such as DMSO-benzene, 25 water-THF or water-dioxane 25 ) can be enhanced by magnetic fields.…”

Section: Introductionmentioning

confidence: 99%

Exciplex fluorescence emission from simple organic intramolecular constructs in non-polar and highly polar media as model systems for DNA-assembled exciplex detectors

et al. 2006

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Organic intramolecular exciplexes, N-(4-dimethylaminobenzyl)-N-(1-pyrenemethyl)amine (1) and N'-4-dimethylaminonaphthyl-N-(1-pyrenemethyl)amine (2), were used as model systems to reveal major factors affecting their exciplex fluorescence, and thus lay the basis for developing emissive target-assembled exciplexes for DNA-mounted systems in solution. These models with an aromatic pyrenyl hydrocarbon moiety as an electron acceptor appropriately connected to an aromatic dimethylamino electron donor component (N,N-dimethylaminophenyl or N,N-dimethylaminonaphthyl) showed strong intramolecular exciplex emission in both non-polar and highly polar solvents. The effect of dielectric constant on the maximum wavelength for exciplex emission was studied, and emission was observed for 1 and 2 over the full range of solvent from non-polar hydrocarbons up to N-methylformamide with a dielectric constant of 182. Quantum yields were determined for these intramolecular exciplexes in a range of solvents relative to that for Hoechst 33,258. Conformational analysis of 1 was performed both computationally and via qualitative 2D NMR using (1)H-NOESY experiments. The results obtained indicated the contribution of pre-folded conformation(s) to the ground state of 1 conducive to exciplex emission. This research provides the initial background for design of self-assembled, DNA-mounted exciplexes and underpins further development of exciplex-based hybridisation bioassays.

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“…Moreover, exciplex emission efficiency dramatically decreases with the solvent polarity. [11][12][13][14] Exciplex emission is also known to be sensitive to solvent polarity. Thus judicious adjustment of solvent properties could favour exciplex emission while maintaining duplex structure both by a specific solvation effect on the charge-separated exciplex structure in the excited state and by balancing the mutual hydrophobic forces operating between the exci-partners as a pair, and between the individual exci-partners and the DNA structure itself.…”

Section: Application To Dna: Proof That the Split-probe Exciplex Systmentioning

confidence: 99%

An Exciplex-Based, Target-Assembled Fluorescence System with Inherently Low Background to Probe for Specific Nucleic Acid Sequences

Bichenkova

Sardarian

Savage

et al. 2005

ASSAY and Drug Development Technologies

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A novel detection technique, called ExciProbes, has been developed to proof-of-principle level for DNA oligonucleotides. The new approach is based on the use of two short oligonucleotides complementary to a target nucleic acid sequence. Each short-probe oligonucleotide bears the separated parts of a new class of fluorescence detector, an exciplex. These isolated parts of the detector have no inherent signal at the detection wavelength. They are designed to detect biotarget by being assembled by the target itself to give a new molecular entity (the exciplex), with a characteristic fluorescence and very large Stokes shift (typically >150 nm). The technique is not related to fluorescence resonance energy transfer, and can potentially resolve to 1 base pair. ExciProbes can detect single or double mutations in a short sequence of DNA, and can be combined with temperature-filtering to provide allelic discrimination of single nucleotide polymorphism analysis. Compared to other fluorophore systems that have large backgrounds (typically >60%), ExciProbes show backgrounds of <1% under comparable conditions, and can be used with DNA, RNA, or synthetic nucleic acids such as locked nucleic acid.

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Solvent induced changes in the electronic structure of a polar intermolecular exciplex

Cited by 32 publications

References 19 publications

Investigation of physical triplet quenching by electron donors

Investigation of physical triplet quenching by electron donors

Exciplex fluorescence emission from simple organic intramolecular constructs in non-polar and highly polar media as model systems for DNA-assembled exciplex detectors

An Exciplex-Based, Target-Assembled Fluorescence System with Inherently Low Background to Probe for Specific Nucleic Acid Sequences

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