Fluorescent Properties of BODIPY Sensors Based on Photoinduced Electron Transfer

Abstract

Two boron-dipyrrin (BODIPY) based dyes with dimethylaminophenyl and carboxyphenyl substituents in 8-position of dipyrrin ligand have been synthesized and characterized. Photophysical and spectral properties of the obtained compounds have been investigated in water-ethanol mixture and water-cyclohexane system with variation of pH values. The equilibria constants of the compounds were identified by classical methods of acid-base titration. BODIPY bearing dimethylaminophenyl and carboxyphenyl subunits show deprotonation/protonation dependent fluorescence off/on-switching. The change of the emission could be mechanistically explained by a PET (photoinduced electron transfer) from the 8-substituent to the fluorophore. The present study demonstrates that BODIPY-based fluorescent sensors can be used to measure the pH in the range of 2-13 extending the scope of BODIPY dyes available as pH-indicators. Investigated compounds demonstrate weak dye-dye interaction allowing their cooperative usage as indicators.

Effects of Substituents on Photophysical and CO-Photoreleasing Properties of 2,6-Substituted meso-Carboxy BODIPY Derivatives

“…It has been explained by the effect of large stabilization upon excitation along with the bending of the fused BODIPY core, and the accessible S1/S0 conical intersection point [16]; the small geometrical evolution prompts the nonradiative relaxation to the ground state [43]. We also cannot exclude fluorescence quenching by internal charge transfer (ICT) in derivatives 9 and 10 [42,44,45]. Different amounts of DMSO were added to PBS to dissolve the BODIPY derivatives because, except for 10 (the p-phenyl polyethylene glycol substituents were introduced in 10 to improve its solubility in aqueous solutions), they are only par- max and λ em max of 6, bearing an electron-withdrawing group at position 2, are slightly hypsochromically shifted.…”

Novel PET-pperated rosamine pH-sensor dyes with substitution pattern-tunable pKa values and temperature sensitivity

“…These modifications are caused by changes in the electron density of the (de)protonable group, which affects the light-induced intramolecular CT process. [16][17][18][19] For the design of PET probes, fluorophores like fluoresceins 20 , naphthalimides 21 , BODIPYs [22][23][24] and aza-BODIPYs, 25 are combined with electron donating (de)protonable moieties with non-bonding electron pairs provided by nitrogen or oxygen atoms. Electronic excitation of these PET probes leads to an electron transfer from the electron rich receptor to the electronically decoupled excited fluorophore promoting fluorescence quenching.…”

Bodipy Based Fluorescent Materials in Cellulose Matrices: Synthesis, Spectral Properties and Vapochromic Fluorescent Recognition of Alcohols and Acetone

“…Luminescent molecular sensors are one of the most prominent among currently used in situ property measurement technologies [1][2][3][4][5][6]. Fluorescent probes demonstrate both intense callback and high versatility, due to the vast range of possible fluorescence quenching mechanisms.…”