TY - JOUR

T1 - Investigating Design Rules for Photoinduced Electron Transfer Quenching in Triangulenium Probes

AU - Dahl Jensen, Jesper

AU - Jakobsen, Rasmus K.

AU - Yao, Zehan

AU - Laursen, Bo W.

N1 - Funding Information: We thank Asst. Prof Junsheng Chen for assisting with streak Camera measurements. This project has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement no. 871124 Laserlab‐Europe. The work was supported by the Novo Nordic Foundation (NNF20OC0062176). Publisher Copyright: © 2023 The Authors. Chemistry - A European Journal published by Wiley-VCH GmbH.

PY - 2023

Y1 - 2023

N2 - Fluorescent probes based on photoinduced electron transfer (PET) quenching of long lifetime triangulenium fluorophores have found multiple applications. For such probes a successful design relies on the right balance between the rate of PET quenching and fluorescence. In a series of ADOTA (A) and DAOTA (D) triangulenium fluorophores appended with aniline-like quencher moieties, we have investigated the rate of quenching and its relation to thermodynamic driving force, distance, and conjugation within the quencher moiety. Three different quenchers, a short (1), a long (2), and a long twisted (3), 4-aminophenyl, 4’-aminobiphenyl, and 2,2’-dimethyl-4’-aminobiphenyl, respectively were investigated. Steady-state spectroscopy and electrochemistry confirms that the quencher moieties are electronically decoupled from the dyes and have similar oxidation potentials and thus driving force for PET quenching, irrespectively of their different length and conjugation. Time-resolved fluorescence measurement was used to measure the fast PET quenching, with rate constant kPET ranging from >4×1011 to 2×109 s−1. Interestingly, PET quenching is equally efficient/fast from 1 and 2, even with increase in distance between the donor and the acceptor. However, when twisting the biphenyl in 3, a 20-fold decrease in quenching is found. Even with this decrease in kPET, the quenching in 3 A/D is still highly efficient, with nearly 99 % quenching. The study show that long lifetime fluorophores can be efficiently switched even by relatively slow PET processes and that PET quencher moieties can be removed far from the fluorophore if conjugated linkers are applied.

AB - Fluorescent probes based on photoinduced electron transfer (PET) quenching of long lifetime triangulenium fluorophores have found multiple applications. For such probes a successful design relies on the right balance between the rate of PET quenching and fluorescence. In a series of ADOTA (A) and DAOTA (D) triangulenium fluorophores appended with aniline-like quencher moieties, we have investigated the rate of quenching and its relation to thermodynamic driving force, distance, and conjugation within the quencher moiety. Three different quenchers, a short (1), a long (2), and a long twisted (3), 4-aminophenyl, 4’-aminobiphenyl, and 2,2’-dimethyl-4’-aminobiphenyl, respectively were investigated. Steady-state spectroscopy and electrochemistry confirms that the quencher moieties are electronically decoupled from the dyes and have similar oxidation potentials and thus driving force for PET quenching, irrespectively of their different length and conjugation. Time-resolved fluorescence measurement was used to measure the fast PET quenching, with rate constant kPET ranging from >4×1011 to 2×109 s−1. Interestingly, PET quenching is equally efficient/fast from 1 and 2, even with increase in distance between the donor and the acceptor. However, when twisting the biphenyl in 3, a 20-fold decrease in quenching is found. Even with this decrease in kPET, the quenching in 3 A/D is still highly efficient, with nearly 99 % quenching. The study show that long lifetime fluorophores can be efficiently switched even by relatively slow PET processes and that PET quencher moieties can be removed far from the fluorophore if conjugated linkers are applied.

KW - fluorescence spectroscopy

KW - organic chromophores

KW - PET quenching

KW - pH probes

KW - ps spectroscopy

KW - triangulenium dyes

U2 - 10.1002/chem.202301077

DO - 10.1002/chem.202301077

M3 - Journal article

C2 - 37261711

AN - SCOPUS:85165269941

VL - 29

JO - Chemistry: A European Journal

JF - Chemistry: A European Journal

SN - 0947-6539

IS - 46

M1 - e202301077

ER -