Calorimetric determinations of absolute fluorescence quantum yields

Olmsted, J.

doi:10.1021/j100483a006

Cited by 625 publications

(489 citation statements)

References 3 publications

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“…Fluorescence spectra were corrected for the wavelength response of the system. Fluorescence quantum yields for the keto form were determined using rhodamine 6G (φ F ) 0.88 in ethanol 34 ) and quinquethiophene (φ F ) 0.36 in dioxane 35 ) as standards. For the reduced (leuco) forms, quaterthiophene (φ F ) 0.18 in dioxane 35 ) was used.…”

Section: Methodsmentioning

confidence: 99%

Photophysics of an Indigo Derivative (Keto and Leuco Structures) with Singular Properties

et al. 2006

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Spectral and photophysical properties of the indigo derivative Cibalackrot in keto and reduced (leuco) forms were studied by absorption spectra, fluorescence and pulse radiolysis and compared with the structurally similar indigo. With the keto form of this dye, fluorescence (φ F ) 0.76) and intersystem crossing (φ T ) 0.11) are dominant, whereas with indigo, efficient internal conversion (φ IC ) 0.99) is observed, probably involving proton transfer through intramolecular hydrogen bonds. With Cibalackrot, this pathway is blocked, supporting the above model for indigo. With the reduced form of Cibalackrot, more than 98% of the absorbed quanta are dissipated through S 1 ∼∼f S 0 internal conversion, which contrasts with leuco-indigo, where fluorescence (φ F ) 0.35), internal conversion (φ IC ) 0.53) and intersystem crossing (φ T ) 0.12 5 ) are found to be competitive. In addition, a synthetic precursor of Cibalackrot (preCiba) was also investigated. This has a rigid molecular structure (with a moiety identical to Cibalackrot and the other to indigo), but intra-or intermolecular proton transfer is allowed between adjacent carbonyl and N-H groups. With this precursor in its keto structure the photophysical parameters are generally very close to those of the keto form of indigo, and different from those of Cibalackrot. A more detailed investigation of the time-decay profiles of preCiba in dioxane (and with added water and D 2 O) has shown that these follow biexponential laws with a shorter component of 14-25 ps, which appears associated with a risetime at longer wavelength emissions (and to a positive preexponential at shorter emission wavelengths) and a longer lived (decay) component of 104-130 ps. In the steady-state spectra of preCiba, the variation with temperature reveals a blue shift of the emission maxima, which is interpreted as the presence (simultaneous emission) of two species (keto and enol) in the excited state. Indigo and deuterated indigo are also found to present a similar behavior. The overall data are interpreted as to be due to an excited-state process involving the proton transfer between keto and enol forms. Rate constants with values of 7 × 10 10 s -1 for preCiba and 1.6 × 10 11 s -1 for deuterated indigo were obtained. This inverse isotope effect is justified on the basis of the proposed model for proton-transfer excited-state deactivation.

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Section: Methodsmentioning

confidence: 99%

Photophysics of an Indigo Derivative (Keto and Leuco Structures) with Singular Properties

et al. 2006

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“…Fluorescence spectra were measured on a Spex Fluorolog II (Spex Industries, Edison, NJ) at 2.2-nm bandwidth for excitation and emission. Fluorescence quantum yield measurements were performed by using crystal violet (Sigma-Aldrich) in methanol at equal optical density at 546 nm as a standard (18). All measurements were performed at 22°C.…”

Section: Methodsmentioning

confidence: 99%

A far-red fluorescent protein with fast maturation and reduced oligomerization tendency from Entacmaea quadricolor (Anthozoa, Actinaria)

Wiedenmann

Schenk

Röcker

et al. 2002

Proc. Natl. Acad. Sci. U.S.A.

239

264

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We performed the biochemical and biophysical characterization of a red fluorescent protein, eqFP611, from the sea anemone Entacmaea quadricolor cloned in Escherichia coli. With an excitation maximum at 559 nm and an emission maximum at 611 nm, the recombinant protein shows the most red-shifted emission and the largest Stokes shift of all nonmodified proteins in the green fluorescent protein family. The protein fluoresces with a high quantum yield of 0.45, although it resembles the nonfluorescent members of this protein class, as inferred from the absence of the key amino acid serine at position 143. Fluorescence is constant within the range pH 4 -10. Red fluorophore maturation reaches a level of 90% after Ϸ12 h by passing through a green intermediate. After complete maturation, only a small fraction of the green species (less than 1%) persists. The protein has a reduced tendency to oligomerize, as shown by its monomeric appearance in SDS͞ PAGE analysis and single-molecule experiments. However, it forms tetramers at higher concentrations in the absence of detergent. Fluorescence correlation spectroscopy reveals light-driven transitions between bright and dark states on submillisecond and millisecond time scales. Applicability of eqFP611 for in vivo labeling in eukaryotic systems was shown by expression in a mammalian cell culture.G reen fluorescent protein from Aequorea victoria (avGFP) and its derivatives have become extremely popular in life science research as protein labels, markers of gene expression, and reporters of environmental conditions in living cells (1-3). Molecular properties of avGFP have been modified by sitedirected mutagenesis to optimize their applicability. Still, some properties, most importantly the restricted range of emission wavelengths, pose severe limitations in certain applications. In particular, red fluorescent proteins (FP) would be highly desirable because of the reduced cellular autofluorescence in the red spectral range and for use in multicolor labeling or fluorescence resonance energy transfer experiments. Efforts to produce stable red-fluorescent avGFP variants have not yet met with success. Recently, however, avGFP homologs were discovered in nonbioluminescent Anthozoa species (4-8). Some of the Anthozoa FPs show spectral properties that deviate greatly from avGFP, including red-emitting variants.One of them, a red FP from the corallimorpharian Discosoma sp. named drFP583 (6), commercially known as DsRed, became the subject of various biochemical and biophysical studies (9-12). These studies revealed detrimental properties for certain applications of the wild-type protein, especially the slow and incomplete maturation of the fluorophore, the obligate formation of tetramers, and the tendency to aggregate. Meanwhile, maturation properties have been greatly improved by engineering the protein, and the tendency to form aggregates was also reduced by mutagenesis (13-15). Recently, the oligomerization problem of DsRed has been solved by mutagenetic means (16).We have continued ...

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“…Luminescence decays were obtained on the PTI Quantamaster instrument over temporal windows covering at least five decay times. Luminescence quantum yields were measured according to conventional procedures, [36] with diluted solutions (optical density < 0.05), by using [RuA C H T U N G T R E N N U N G (bipy) 3 ]Cl 2 in nondegassed water (F = 2.8 %) [37] or rhodamine 6G in ethanol (F = 88 %) [38] as references, with the necessary correction for refractive index of the media used. [39] Estimated errors are AE 15 %.…”

Section: Methodsmentioning

confidence: 99%

Relationship Between the Ligand Structure and the Luminescent Properties of Water‐Soluble Lanthanide Complexes Containing Bis(bipyridine) Anionic Arms

Charbonnière

Weibel

Retailleau

et al. 2006

Chemistry A European J

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A series of six new ligands (L1–L6) suitable for the formation of luminescent lanthanide complexes in water is described. Ligands L1–L4 are constructed from two 6′‐carboxy‐6‐methylene‐2,2′‐bipyridine chromophoric arms bonded to the amino function of a 2‐aminomethylene‐6‐carboxy‐pyridine (L1), an N,N‐diacetate‐ethylene diamine (L2), a serine (L3), or an aminomalonic acid (L4). For ligands L5 and L6, the linking amino function is provided by a glutamic acid, and the anionic functions at the 6′‐position of the bipyridyl arms are made of the sodium salts of monoethylphosphonic ester (L5) and phosphonic acid (L6). The synthesis and characterisation of the ligands are described, together with the study of the formation of lanthanide complexes with europium and terbium. In the case of L3, the europium complex obtained in acidic conditions was crystallised and the X‐ray crystal structure is depicted. Photophysical properties of the complexes were studied by means of UV‐visible absorption, and steady‐state and time‐resolved luminescence spectroscopy. Excited‐state luminescence lifetimes of the complexes were determined in water and deuterated water to gain insight into the number of water molecules directly coordinated in the first coordination sphere of the complexes. The coordination behaviour of the series of ligands is questioned in the light of the spectroscopic data and discussed in terms of protection of the cation towards water molecules and their impact on the luminescence efficiency.

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Calorimetric determinations of absolute fluorescence quantum yields

Cited by 625 publications

References 3 publications

Photophysics of an Indigo Derivative (Keto and Leuco Structures) with Singular Properties

Photophysics of an Indigo Derivative (Keto and Leuco Structures) with Singular Properties

A far-red fluorescent protein with fast maturation and reduced oligomerization tendency from Entacmaea quadricolor (Anthozoa, Actinaria)

Relationship Between the Ligand Structure and the Luminescent Properties of Water‐Soluble Lanthanide Complexes Containing Bis(bipyridine) Anionic Arms

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