Impact of Changing the Core in Tetrapyrrolic Dendrimers Designed for Oxygen Sensitization: New Fluorescent Phthalocyanine-Based Dendrimers with High Two-Photon Absorption Cross-sections

Seifallah Abid (1, 2) , Sarra Ben Hassine (2, 3) , Zhipeng Sun (2) , Nicolas Richy (2) , Franck Camerel (2) , Bassem Jamoussi (4) , Mireille Blanchard‐desce (5) , Olivier Mongin (2) , Frédéric Paul (2) , Christine Paul-Roth (2)

1 UCAR - Université de Carthage (Tunisie)
2 ISCR - Institut des Sciences Chimiques de Rennes
3 University of Tunis El Manar
4 King Abdulaziz University
5 ISM - Institut des Sciences Moléculaires

In the continuation of our sustained interest for porphyrin-based dendrimers and their use as luminescent photo-sensitizers for two-photon photodynamic therapy (2P-PDT), we wondered about the effect of changing the central porphyrin core for a phthalocyanine core in these macromolecular structures. Thus, related phthalocyanine-based dendrimers possessing up to 16 conjugated 9,9-dibutyl-2-fluorenyl endgroups at their periphery were now prepared and studied. As for porphyrin analogues, it was found that an efficient energy transfer occurs from the peripheral fluorenyl units toward the central phthalocyanine unit of these compounds, leading to intense red light emission and photosensitization of oxygen. While the linear optical properties of these new dendrimers are only slightly improved compared to those of their porphyrin-cored analogues for PDT and fluorescence imaging, their two-photon absorption (2PA) cross-sections are much more significantly boosted, evidencing the key role played by the central tetrapyrrolic unit in this respect. The impact of this structural change in relation with the impact resulting from the change in dendrimer generations is then discussed with the help of DFT and molecular dynamic calculations.

Mots clés: Absorption; Phthalocyanine; Molecules; Oxygen; Dendrons

Domaines: Chimie

Seifallah Abid, Sarra Ben Hassine, Zhipeng Sun, Nicolas Richy, Franck Camerel, et al.. Impact of Changing the Core in Tetrapyrrolic Dendrimers Designed for Oxygen Sensitization: New Fluorescent Phthalocyanine-Based Dendrimers with High Two-Photon Absorption Cross-sections. Macromolecules, 2021, 54 (14), pp.6726-6744. ⟨10.1021/acs.macromol.1c00830⟩. ⟨hal-03331154⟩