TY - JOUR

T1 - 2-(Indol-3-yl)- and 6-(pyrrol-2-yl)-substituted (bi)pyridine-based AIE-probes/fluorophores: Synthesis and photophysical studies

AU - Starnovskaya, Ekaterina S.

AU - Savchuk, Maria I.

AU - Kopchuk, Dmitry S

AU - Taniya, Olga S

AU - Khasanov, Albert F

AU - Novikov, Alexander S.

AU - Slovesnova, Natalya V

AU - Minin, Artem S.

AU - Santra, Sougata

AU - Zyryanov, Grigory V

PY - 2023/11/3

Y1 - 2023/11/3

N2 - A series of new indolyl- and pyrrolyl-substituted 2,2′-bipyridines were reported as push–pull fluorophores/probes by using a sequence of the nucleophilic substitution reaction of hydrogen (S N H) and inverse-demand Diels–Alder reaction. A series of new 2-(indol-3-yl)-6-(hetero)aryl substituted pyridines, 2-(indol-3-yl)-5-phenyl-substituted 2,2′-bipyridine and 5-aryl-6-(pyrrol-2-yl) substituted 2,2′-bipyridines were synthesized as push–pull fluorophores/probes by using a sequence of nucleophilic substitution reaction of hydrogen (S N H) and inverse-demand Diels–Alder reaction. For the obtained compounds, photophysical properties were studied. All the compounds displayed ICT-activity with a large Stokes shift (up to 197 nm) and PLQY up to 0.28. Due to dual emission in polar solvents, one specific probe was able to respond to the action of the local pH changes in the microenvironment and exhibit AIE-activity. The fluorescence titration data at different pH were analyzed to estimate a p K a value of 4.50 for that specific probe. The AIE behavior was further confirmed by means of time-resolved fluorescence lifetime measurements as well as UV-vis spectroscopic studies. The correlation of the influence of the nature of substituents on the degree of ICT state was established based on the analysis of charge transfer (CT) indices and the calculated interfragment charge transfer (IFCT) values. Finally, the fluorophores reported in this study were successfully applied for cellular imaging.

AB - A series of new indolyl- and pyrrolyl-substituted 2,2′-bipyridines were reported as push–pull fluorophores/probes by using a sequence of the nucleophilic substitution reaction of hydrogen (S N H) and inverse-demand Diels–Alder reaction. A series of new 2-(indol-3-yl)-6-(hetero)aryl substituted pyridines, 2-(indol-3-yl)-5-phenyl-substituted 2,2′-bipyridine and 5-aryl-6-(pyrrol-2-yl) substituted 2,2′-bipyridines were synthesized as push–pull fluorophores/probes by using a sequence of nucleophilic substitution reaction of hydrogen (S N H) and inverse-demand Diels–Alder reaction. For the obtained compounds, photophysical properties were studied. All the compounds displayed ICT-activity with a large Stokes shift (up to 197 nm) and PLQY up to 0.28. Due to dual emission in polar solvents, one specific probe was able to respond to the action of the local pH changes in the microenvironment and exhibit AIE-activity. The fluorescence titration data at different pH were analyzed to estimate a p K a value of 4.50 for that specific probe. The AIE behavior was further confirmed by means of time-resolved fluorescence lifetime measurements as well as UV-vis spectroscopic studies. The correlation of the influence of the nature of substituents on the degree of ICT state was established based on the analysis of charge transfer (CT) indices and the calculated interfragment charge transfer (IFCT) values. Finally, the fluorophores reported in this study were successfully applied for cellular imaging.

UR - https://www.mendeley.com/catalogue/02a7c502-305b-3b49-8525-3dbe6f102932/

U2 - 10.1039/d3nj04051h

DO - 10.1039/d3nj04051h

M3 - Article

JO - New Journal of Chemistry

JF - New Journal of Chemistry

SN - 1144-0546

ER -