AI Article Synopsis

  • The study examines the excited-state dynamics of three push-pull isomers featuring a phenothiazine donor and benzothiazole acceptor, showcasing efficient intersystem crossing and singlet oxygen production.
  • The research highlights the observation of room-temperature phosphorescence in both solid-state and biocompatible water dispersions, a rare finding in similar compounds.
  • These isomers show potential for photodynamic therapy, as they can be taken up by cancer cells and generate reactive oxygen species upon light exposure, causing phototoxic effects.

Article Abstract

In this study, we report a comprehensive time-resolved spectroscopic investigation of the excited-state deactivation mechanism in three push-pull isomers characterized by a phenothiazine electron donor, a benzothiazole electron acceptor, and a phenyl π-bridge where the connection is realized at the relative , , and positions. Spin-orbit charge-transfer-induced intersystem crossing takes place with high yield in these all-organic donor-acceptor compounds, leading also to efficient production of singlet oxygen. Our spectroscopic results give clear evidence of room-temperature phosphorescence not only in solid-state host-guest matrices but also in highly biocompatible aggregates of these isomers produced in water dispersions, as rarely reported in the literature. Moreover, aggregates of the isomers could be internalized by lung cancer and melanoma cells and display bright luminescence without any dark cytotoxic effect. On the other hand, the isomers showed significant cellular phototoxicity against the tumor cells due to light-induced reactive oxygen species generation. Our findings strongly suggest that nanoaggregates of the investigated isomers are promising candidates for imaging-guided photodynamic therapy.

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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC9940226PMC
http://dx.doi.org/10.1021/acs.jpcb.2c07717DOI Listing

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