RT Journal Article T1 Site-selected thionated benzothioxanthene chromophores as heavy-atom-free small-molecule photosensitizers for photodynamic therapy A1 Deiana, Marco A1 Josse, Pierre A1 Dalinot, Clément A1 Osmolovskyi, Artem A1 Simón Marqués, Pablo A1 Andrés Castán, José María A1 Abad Galán, Laura A1 Allain, Magali A1 Khrouz, Lhoussain A1 Maury, Olivier A1 Le Bahers, Tangui A1 Blanchard, Philippe A1 Dabos-Seignon, Sylvie A1 Monnereau, Cyrille A1 Sabouri, Nasim A1 Cabanetos, Clément AB Photodynamic therapy is a clinically approved anticancer modality that employs a light-activated agent (photosensitizer) to generate cytotoxic reactive oxygen species (ROS). There is therefore a growing interest for developing innovative photosensitizing agents with enhanced phototherapeutic performances. Herein, we report on a rational design synthetic procedure that converts the ultrabright benzothioxanthene imide (BTI) dye into three heavy-atom-free thionated compounds featuring close-to-unit singlet oxygen quantum yields. In contrast to the BTI, these thionated analogs display an almost fully quenched fluorescence emission, in agreement with the formation of highly populated triplet states. Indeed, the sequential thionation on the BTI scaffold induces torsion of its skeleton reducing the singlet-triplet energy gaps and enhancing the spin-orbit coupling. These potential PSs show potent cancer-cell ablation under light irradiation while remaining non-toxic under dark condition owing to a photo-cytotoxic mechanism that we believe simultaneously involves singlet oxygen and superoxide species, which could be both characterized in vitro. Our study demonstrates that this simple site-selected thionated platform is an effective strategy to convert conventional carbonyl-containing fluorophores into phototherapeutic agents for anticancer PDT. PB Springer Nature SN 2399-3669 YR 2022 FD 2022 LK https://hdl.handle.net/20.500.14352/92076 UL https://hdl.handle.net/20.500.14352/92076 LA eng NO Deiana, Marco, et al. «Site-Selected Thionated Benzothioxanthene Chromophores as Heavy-Atom-Free Small-Molecule Photosensitizers for Photodynamic Therapy». Communications Chemistry, vol. 5, n.o 1, octubre de 2022, p. 142. https://doi.org/10.1038/s42004-022-00752-x. NO Umea University (Suecia) DS Docta Complutense RD 12 abr 2025