New Fluorescent Porphyrins with High Two-Photon Absorption Cross-Sections Designed for Oxygen-Sensitization: Impact of Changing the Connectors in the Peripheral Arms

In the continuation of our sustained interest in porphyrin-based dendrimers and their use as luminescent photosensitizers for two-photon photodynamic therapy (2P-PDT), we wondered about effect changing connectors macromolecular structures. We also wanted to initiate preliminary studies on meso-tetraarylporphyrins decorated with more electron-releasing arms. Thus, various meso-tetrafluorenylporphyrin-cored star-shaped dendrimeric derivatives have been synthesized characterized, well zinc(II) complexes. new derivatives, peripheral fluorenyl units dendrons are linked inner core either by N-phenylcarbazole (CCbz) or triphenylamine (CTpa) instead classic 1,3,5-phenylene (CPh) linkers previously used us. Selected linear non-linear optical (LO NLO) properties were then determined these compounds via absorption emission excited fluorescence (TPEF) measurements. It was found that CCbz-containing dendrimer, which has most rigid structure, exhibits a significantly lower (2PA) cross-section than its CTpa analog, presenting flexible structure while rather similar luminescence singlet oxygen activation quantum yields both. The origin this unexpected discrepancy is briefly discussed based photophysical data. demonstrated latter dendrimer outperforms several closely related terms 2PA action 2PA-oxygen sensitization, making molecular architecture quite appealing developing suited theranostic uses.