A tetrazole-ene photoactivatable fluorophore with improved brightness and stability in protic solution

Abstract

The pyrazoline fluorophore, generated by photoinduced tetrazole-ene cycloaddition, showed faint fluorescence in protic solvents. To suppress this fluorescence-quenching, we rationally designed a series of substituted diaryl tetrazoles at N-side phenyl...

Fluorescence turn-on by photoligation – bright opportunities for soft matter materials

“…Modication of the N-phenyl moiety not only provides the opportunity to adjust the activation wavelength, yet improve the quantum efficiency and photostability of the resultant pyrazoline uorophores, facilitating enhanced imaging of targeted cellular components. 71,72 For example, the inclusion of a bis(-triuoromethyl)benzene substituent results in a 10-fold increase in the uorescence quantum yield (4 F = 0.42 vs. 0.04) of the pyrazole adduct compared to the non-substituted phenyl ring. 71 It should be noted that even when a tetrazole exhibits absorption in the visible region, there is no guarantee for nitrile imine formation by irradiation within such a wavelength window, due to the potential vibrational (non-radiative) deactivation of the singlet excited state, as observed in dimethylamino-biphenyl-functionalised tetrazole.…”

“…71,72 For example, the inclusion of a bis(-triuoromethyl)benzene substituent results in a 10-fold increase in the uorescence quantum yield (4 F = 0.42 vs. 0.04) of the pyrazole adduct compared to the non-substituted phenyl ring. 71 It should be noted that even when a tetrazole exhibits absorption in the visible region, there is no guarantee for nitrile imine formation by irradiation within such a wavelength window, due to the potential vibrational (non-radiative) deactivation of the singlet excited state, as observed in dimethylamino-biphenyl-functionalised tetrazole. 36 Furthermore, the preparation of tetrazole molecules with redshied photoreactivity and bulky substituents can be demanding, oen involving multiple synthesis steps with low to moderate yield (10-50%) in each step.…”

Metabolic labelling of DNA in cells by means of the “photoclick” reaction triggered by visible light

“…This bioconjugation is suitable in particular for DNA as it combines high reactivity induced by visible light with fluorogenicity for metabolic labelling in cells. There are reports on photoactivatable fluorophores 13 and photocages 14 to control the reactions by light, but to the best of our knowledge, visible light 15 has not yet been used for the metabolic labelling of nucleic acids. This is disappointing because the use of light has the intrinsic property of spatiotemporal resolution.…”

Metabolic Labelling of DNA in Cells by Means of the “Photoclick” Reaction Triggered by Visible Light

“…This bioconjugation is suitable in particular for DNA as it combines high reactivity induced by visible light with fluorogenicity for metabolic labelling in cells. There are reports on photoactivatable fluorophores 12 and photocages 13 to control the reactions by light, but to the best of our knowledge, visible light 14 has not yet been used for metabolic labelling of nucleic acids. This is disappointing because the use of light has the intrinsic property of spatiotemporal resolution.…”