Premium
Deciphering the Electronic Transitions of Thiophene‐Based Donor‐Acceptor‐Donor Pentameric Ligands Utilized for Multimodal Fluorescence Microscopy of Protein Aggregates
Author(s) -
Gustafsson Camilla,
Shirani Hamid,
Leira Petter,
Rehn Dirk R.,
Linares Mathieu,
Nilsson K. Peter R.,
Norman Patrick,
Lindgren Mikael
Publication year - 2021
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.202000669
Subject(s) - thiophene , chemistry , fluorescence , photochemistry , quenching (fluorescence) , acceptor , fluorescence microscope , excited state , microscopy , crystallography , organic chemistry , physics , quantum mechanics , nuclear physics , optics , condensed matter physics
Anionic pentameric thiophene acetates can be used for fluorescence detection and diagnosis of protein amyloid aggregates. Replacing the central thiophene unit by benzothiadiazole (BTD) or quinoxaline (QX) leads to large emission shifts and basic spectral features have been reported [ Chem. Eur. J . 2015 , 21 , 15133‐13137]. Here we present new detailed experimental results of solvent effects, time‐resolved fluorescence and examples employing multi‐photon microscopy and lifetime imaging. Quantum chemical response calculations elucidate how the introduction of the BTD/QX groups changes the electronic states and emissions. The dramatic red‐shift follows an increased conjugation and quinoid character of the π‐electrons of the thiophene backbone. An efficient charge transfer in the excited states S 1 and S 2 compared to the all‐thiophene analogue makes these more sensitive to the polarity and quenching by the solvent. Taken together, the results guide in the interpretation of images of stained Alzheimer disease brain sections employing advanced fluorescence microscopy and lifetime imaging, and can aid in optimizing future fluorescent ligand development.