A Water‐Soluble Fluorescent 2,5‐bis(arylethynyl)rhodacyclopentadiene for Live‐Cell Imaging and Sensing of DNA, RNA, and Protein (BSA)
Abstract
A water-soluble and water-stable 2,5-bis(arylethynyl)rhodacyclopentadiene (4a) containing terminal 4-Me3N–C6H4 groups has been synthesized for bioimaging and sensing of biomolecules, and its linear and nonlinear optical properties investigated. Complex 4a exhibits fluorescence from the S1 excited state in both organic and aqueous solutions, with no observable phosphorescence from T1 at RT. However, competitive intersystem crossing (ISC) to T1 leads to potent 1O2 sensitization. DFT calculations show that the HOMO and LUMO are essentially ligand-localized with very modest contributions from Rh, leading to slow S1 → T1 ISC and competitive fluorescence and triplet state formation, typical of such 2,5-bis(arylethynyl)rhodacyclopentadienes. Complex 4a shows a two-photon absorption cross-section of 290 GM at 680 nm. It binds strongly to DNA, RNA, and protein (BSA) with similar affinities, but gives opposite fluorimetric response, the emission being strongly enhanced for BSA but efficiently quenched by DNA/RNA. Compound 4a efficiently enters living human cells and accumulates preferentially in mitochondrial membranes, being nontoxic even at high (10 µM) concentrations. Although 4a is a potent 1O2 sensitizer in a cuvette, exposure of the complex to intense visible light inside human cell results in fast bleaching of 4a with no effect on cell viability, suggesting local consumption of 1O2 by the complex.
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BibTeX
@article{ghosh2026watersoluble,
title = {{A Water‐Soluble Fluorescent 2,5‐bis(arylethynyl)rhodacyclopentadiene for Live‐Cell Imaging and Sensing of DNA, RNA, and Protein (BSA)}},
author = {Shishir Ghosh and Florian Kerner and Tim Görlich and Alexandra Friedrich and Sabine Lorenzen and Jörn Nitsch and Evripidis Michail and Christoph Lambert and Anissa Amar and Abdou Boucekkine and Jean-François Halet and Marta Jurković and Ksenija Božinović and Ivo Piantanida and Todd B. Marder},
journal = {ChemPhotoChem},
year = {2026},
month = aug,
doi = {10.1002/cptc.70228},
url = {https://hal.science/hal-05741410v1},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - A Water‐Soluble Fluorescent 2,5‐bis(arylethynyl)rhodacyclopentadiene for Live‐Cell Imaging and Sensing of DNA, RNA, and Protein (BSA)
AU - Shishir Ghosh
AU - Florian Kerner
AU - Tim Görlich
AU - Alexandra Friedrich
AU - Sabine Lorenzen
AU - Jörn Nitsch
AU - Evripidis Michail
AU - Christoph Lambert
AU - Anissa Amar
AU - Abdou Boucekkine
AU - Jean-François Halet
AU - Marta Jurković
AU - Ksenija Božinović
AU - Ivo Piantanida
AU - Todd B. Marder
PY - 2026
DA - 2026/08/15
JO - ChemPhotoChem
DO - 10.1002/cptc.70228
UR - https://hal.science/hal-05741410v1
AB - A water-soluble and water-stable 2,5-bis(arylethynyl)rhodacyclopentadiene (4a) containing terminal 4-Me3N–C6H4 groups has been synthesized for bioimaging and sensing of biomolecules, and its linear and nonlinear optical properties investigated. Complex 4a exhibits fluorescence from the S1 excited state in both organic and aqueous solutions, with no observable phosphorescence from T1 at RT. However, competitive intersystem crossing (ISC) to T1 leads to potent 1O2 sensitization. DFT calculations show that the HOMO and LUMO are essentially ligand-localized with very modest contributions from Rh, leading to slow S1 → T1 ISC and competitive fluorescence and triplet state formation, typical of such 2,5-bis(arylethynyl)rhodacyclopentadienes. Complex 4a shows a two-photon absorption cross-section of 290 GM at 680 nm. It binds strongly to DNA, RNA, and protein (BSA) with similar affinities, but gives opposite fluorimetric response, the emission being strongly enhanced for BSA but efficiently quenched by DNA/RNA. Compound 4a efficiently enters living human cells and accumulates preferentially in mitochondrial membranes, being nontoxic even at high (10 µM) concentrations. Although 4a is a potent 1O2 sensitizer in a cuvette, exposure of the complex to intense visible light inside human cell results in fast bleaching of 4a with no effect on cell viability, suggesting local consumption of 1O2 by the complex.
SN - 2367-0932
ER -