Direct probing of ion pair formation using a symmetric triangulenium dye

Westerlund, Fredrik; Elm, Jonas; Lykkebo, Jacob; Carlsson, Nils; Thyrhaug, Erling; Åkerman, Björn; Sørensen, Thomas Just; Mikkelsen, Kurt V.; Laursen, Bo W.

doi:10.1039/c1pp05253e

Cited by 28 publications

(34 citation statements)

References 51 publications

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“…As these red shifts are significantly larger than seen in 2-propanol, there are other factors involved beside simple polarity of the microenvironment. The local oriented dipoles of DOPC and counter ion effects are most likely the origin of these spectral shifts [30]–[31].…”

Section: Resultsmentioning

confidence: 99%

Long-Lived Bright Red Emitting Azaoxa-Triangulenium Fluorophores

et al. 2013

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The fluorescence lifetimes of most red emitting organic probes are under 4 nanoseconds, which is a limiting factor in studying interactions and conformational dynamics of macromolecules. In addition, the nanosecond background autofluorescence is a significant interference during fluorescence measurements in cellular environment. Therefore, red fluorophores with longer lifetimes will be immensely helpful.Azaoxa-triangulenium fluorophores ADOTA and DAOTA are red emitting small organic molecules with high quantum yield, long fluorescence lifetime and high limiting anisotropy. In aqueous environment, ADOTA and DAOTA absorption and emission maxima are respectively 540 nm and 556 nm, and 556 nm and 589 nm. Their emission extends beyond 700 nm. Both probes have the limiting anisotropy between 0.36–0.38 at their absorption peak. In both protic and aprotic solvents, their lifetimes are around 20 ns, making them among the longest-lived red emitting organic fluorophores. Upon labeling of avidin, streptavidin and immunoglobulin their absorption and fluorescence are red-shifted. Unlike in free form, the protein-conjugated probes have heterogeneous fluorescence decays, with the presence of both significantly quenched and unquenched populations. Despite the presence of significant local motions due to a flexible trimethylene linker, we successfully measured both intermediate nanosecond intra-protein motions and slower rotational correlation times approaching 100 ns. Their long lifetimes are unaffected by the cell membrane (hexadecyl-ADOTA) and the intra-cellular (DAOTA-Arginine) localization. Their long lifetimes also enabled successful time-gating of the cellular autofluorescence resulting in background-free fluorescence lifetime based images.ADOTA and DAOTA retain a long fluorescence lifetime when free, as protein conjugate, in membranes and inside the cell. Our successful measurements of intermediate nanosecond internal motions and long correlations times of large proteins suggest that these probes will be highly useful to study slower intra-molecular motions and interactions among macromolecules. The fluorescence lifetime facilitated gating of cellular nanosecond autofluorescence should be of considerable help in in vitro and in vivo applications.

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Section: Resultsmentioning

confidence: 99%

Long-Lived Bright Red Emitting Azaoxa-Triangulenium Fluorophores

et al. 2013

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“…13b, 13c, 17 They have high oscillator strengths (ε ≈ 80,000-130,000 M −1 cm −1 ) and quantum yields (Φ ≈ 0.7), lifetimes in the 3-5 ns range, and feature very narrow bands in both absorption and emission.…”

Section: Introductionmentioning

confidence: 99%

Polarization and Symmetry of Electronic Transitions in Long Fluorescence Lifetime Triangulenium Dyes

et al. 2013

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To fully exploit the capabilities of fluorescence probes in modern experiments, where advanced instrumentation is used to probe complex environments, other photophysical properties than emission color and emission intensity are monitored. Each dye property can be addressed individually as well as collectively to provide in-depth information unavailable from the standard intensity measurements. Dyes with long emission lifetimes and strongly polarized transitions enable the monitoring of lifetime changes as well as emission polarization (or anisotropy). Thus experiments can be designed to follow slow dynamics. In this article the UV and visible electronic transitions of a series of red emitting dyes based on the triangulenium motif are investigated. We resolve overlapping features in the spectra and assign transition moment of the molecular axes. The result is the complete Jablonski diagram for the UV and visible spectral region. The symmetries of the studied dyes are shown to have a large influence on the optical response and they are clearly separated into two groups of symmetry by their photophysical properties. The C2v symmetric dyes: azadioxatriangulenium (ADOTA+) and diazaoxatriangulenium (DAOTA+) have high emission anisotropies, fluorescence lifetimes around 20 ns, and fluorescence quantum yields of ~50%. The trioxatriangulenium (TOTA+) and triazatriangulenium (TATA+) dyes—nominally of D3h symmetry—have fluorescence lifetimes around 10 ns lifetimes and fluorescence quantum yields of 10-15%. However, the D3h-symmetry is shown to be lowered to a point group, where the axes transform uniquely such that the degeneracy of the E’-states is lifted.

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“…In recent years, the improved methods of direct ion pair study have been used (Westerlund et al, 2011;Besser-Rogac et al, 2011;.…”

Section: A-m a Batukaev Et Al: Ion Association In Water Solution mentioning

confidence: 99%

Ion association in water solution of soil and vadose zone of chestnut saline solonetz as a driver of terrestrial carbon sink

Batukaev

Endovitsky²,

Andreev³

et al. 2016

Solid Earth

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Abstract. The assessment of soil and vadose zone as the drains for carbon sink and proper modeling of the effects and extremes of biogeochemical cycles in the terrestrial biosphere are the key components to understanding the carbon cycle, global climate system, and aquatic and terrestrial system uncertainties. Calcium carbonate equilibrium causes saturation of solution with CaCO 3 , and it determines its material composition, migration and accumulation of salts. In a solution electrically neutral ion pairs are formed: CaCO 0 3 , CaSO 0 4 , MgCO 0 3 , and MgSO 0 4 , as well as charged ion pairs CaHCO, CaOH + , and MgOH + . The calcium carbonate equilibrium algorithm, mathematical model and original software to calculate the real equilibrium forms of ions and to determine the nature of calcium carbonate balance in a solution were developed. This approach conducts the quantitative assessment of real ion forms of solution in solonetz soil and vadose zone of dry steppe taking into account the ion association at high ionic strength of saline soil solution. The concentrations of free and associated ion form were calculated according to analytical ion concentration in real solution. In the iteration procedure, the equations were used to find the following: ion material balance, a linear interpolation of equilibrium constants, a method of ionic pairs, the laws of initial concentration preservation, operating masses of equilibrium system, and the concentration constants of ion pair dissociation. The coefficient of ion association γ e was determined as the ratio of ions free form to analytical content of ion γ e = C ass /C an . Depending on soil and vadose zone layer, concentration and composition of solution in the ionic pair's form are 11-52 % Ca 2+ ; 22.2-54.6 % Mg 2+ ;1.1-10.5 % Na + ; 3.7-23.8 HCO 3 . The carbonate system of soil and vadose zone water solution helps to explain the evolution of salted soils, vadose and saturation zones, and landscape. It also helps to improve the soil maintenance, plant nutrition and irrigation.The association of ions in soil solutions is one of the drivers promoting transformation of solution, excessive fluxes of carbon in the soil, and loss of carbon from soil through vadose zone.

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Direct probing of ion pair formation using a symmetric triangulenium dye

Cited by 28 publications

References 51 publications

Long-Lived Bright Red Emitting Azaoxa-Triangulenium Fluorophores

Long-Lived Bright Red Emitting Azaoxa-Triangulenium Fluorophores

Polarization and Symmetry of Electronic Transitions in Long Fluorescence Lifetime Triangulenium Dyes

Ion association in water solution of soil and vadose zone of chestnut saline solonetz as a driver of terrestrial carbon sink

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