Abstract
With the continuing development of advanced fluorescence techniques such as single-molecule fluorescence, time-gated detection, multiple laser pulse excitation, anisotropy decay assays and quenching experiments, fluorescent dyes are needed whose focus does not only lie on classic emission amplitude and energy but on other exploitable spectroscopical characteristics such as the fluorescence lifetime and highly polarized transitions inherent to the chromophores’ structure.
Azaoxatriangulenium salts combine these important features. These chromophore systems are rigid and planar, hetero-atom bridged triarylcarbenium structures of outstanding stability and their spectroscopic properties are indifferent towards changes in pH and solvent polarity. The salts exhibit moderate molar absorbance coefficients (8000-16000 M-1cm-1) in the red spectral range and have fluorescence quantum yields of up to 0.66 in acetonitrile. Their saliently high lifetimes of up to 23 ns in acetonitrile allow for autofluorescence eliminating time-gated measurements; combined with their strongly polarized transitions they enable the measurement of slow protein dynamics. Synthetic strategies developed by Laursen and Krebs allow for simple derivatisation and functionalisation.
In this project the synthesis, spectroscopic characterisation, and comparison of reactive azaoxatriangulenium fluorophores for biolabeling experiments were exploited. Rigid linker moieties with both amine reactive active esters and sulfhydryl binding maleimides were introduced into the azadioxa- and diazaoxa-triangulenium chromophores. The effect of the linker rigidity on the local mobility of the fluorophore on protein surfaces and the resulting retardation of initial emission anisotropy loss in time-resolved experiments were then investigated.
Fluorophores absorbing in the near infrared part of the spectrum are highly desired for biological imaging as another mean of eliminating background signals. Therefore, a fluorophore system closely related to the triangulenium core with red-shifted absorption and emission properties, as compared to DAOTA was synthesized. Unfortunately, the desired characteristics such as the high lifetime and quantum yield were not being preserved in polar solvents.
Unrelated to the development of triangulenium fluorophores, BODIPY based rotors were synthesised and characterized; a previously reported homodimeric rotor structure and a novel, highly absorptive homotrimeric rotor. Non-rotating reference compounds were as well prepared and used in comparison. These probes can serve as molecular viscometers, whose lifetimes and emission intensity show a linear dependence on the viscosity of their surrounding medium. Thus, they are able to detect fluid viscosity on the microscopic scale and can potentially find application in mapping viscosity differences in cells and tissue. In collaboration with my partners, the photophysical properties and their performance as viscosity sensors were investigated.
Azaoxatriangulenium salts combine these important features. These chromophore systems are rigid and planar, hetero-atom bridged triarylcarbenium structures of outstanding stability and their spectroscopic properties are indifferent towards changes in pH and solvent polarity. The salts exhibit moderate molar absorbance coefficients (8000-16000 M-1cm-1) in the red spectral range and have fluorescence quantum yields of up to 0.66 in acetonitrile. Their saliently high lifetimes of up to 23 ns in acetonitrile allow for autofluorescence eliminating time-gated measurements; combined with their strongly polarized transitions they enable the measurement of slow protein dynamics. Synthetic strategies developed by Laursen and Krebs allow for simple derivatisation and functionalisation.
In this project the synthesis, spectroscopic characterisation, and comparison of reactive azaoxatriangulenium fluorophores for biolabeling experiments were exploited. Rigid linker moieties with both amine reactive active esters and sulfhydryl binding maleimides were introduced into the azadioxa- and diazaoxa-triangulenium chromophores. The effect of the linker rigidity on the local mobility of the fluorophore on protein surfaces and the resulting retardation of initial emission anisotropy loss in time-resolved experiments were then investigated.
Fluorophores absorbing in the near infrared part of the spectrum are highly desired for biological imaging as another mean of eliminating background signals. Therefore, a fluorophore system closely related to the triangulenium core with red-shifted absorption and emission properties, as compared to DAOTA was synthesized. Unfortunately, the desired characteristics such as the high lifetime and quantum yield were not being preserved in polar solvents.
Unrelated to the development of triangulenium fluorophores, BODIPY based rotors were synthesised and characterized; a previously reported homodimeric rotor structure and a novel, highly absorptive homotrimeric rotor. Non-rotating reference compounds were as well prepared and used in comparison. These probes can serve as molecular viscometers, whose lifetimes and emission intensity show a linear dependence on the viscosity of their surrounding medium. Thus, they are able to detect fluid viscosity on the microscopic scale and can potentially find application in mapping viscosity differences in cells and tissue. In collaboration with my partners, the photophysical properties and their performance as viscosity sensors were investigated.
| Originalsprog | Engelsk |
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| Forlag | Department of Chemistry, Faculty of Science, University of Copenhagen |
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| Status | Udgivet - 2015 |