Integrating Twisted and Push-Pull Structural Motifs for Efficient Dual-Functioning Near-Infrared BODIPY Photosensitizers

Year: 2026

Authors: Theysmans N., Fraiponts M., Sambucari G., Reynders L., Deckers J., Patrizi B., Van Hecke K., Lutsen L., Ethirajan A., Di Donato M., Champagne B., Maes W.

Autors Affiliation: UHasselt, Inst Mat Res IUMAT, Design & Synth Organ Semicond DSOS, Hasselt, Belgium; imec, IUMAT, Diepenbeek, Belgium; Univ Namur, Namur Inst Struct Matter, Theoret & Struct Phys Chem Unit, Lab Theoret Chem LTC, Namur, Belgium; LENS European Lab Non Linear Spect, Sesto Fiorentino, FI, Italy; CNR INO, Sesto Fiorentino, FI, Italy; Univ Ghent, Dept Chem, XStruct, Ghent, Belgium; UHasselt, Inst Mat Res IUMAT, Nanobiophys & Soft Matter Interfaces NSI Grp, Hasselt, Belgium; Inst Chim Composti Organometall ICCOM CNR, Sesto Fiorentino, FI, Italy.

Abstract: Two strategies to achieve high singlet oxygen quantum yields are uniquely combined here into a single BODIPY-based scaffold for dual-functioning near-infrared photosensitizers. A twisted BODIPY core is functionalized with electron-donating moieties via Knoevenagel condensation with the aim to take advantage of both twist-induced and spin-orbit charge-transfer intersystem crossing and thereby realize efficient triplet generation. All the synthesized molecules exhibit red-shifted absorption and emission, falling into the phototherapeutic window, and varying ratios of singlet oxygen production and fluorescence emission. In particular, the BODIPY derivative decorated with a dimethylacridine donor displays a favorable balance between singlet oxygen and fluorescence quantum yields (in chloroform medium). Quantum-chemical analysis suggests that the high singlet oxygen quantum yields primarily result from spin-orbit charge-transfer intersystem crossing, with transient absorption spectroscopy confirming the involvement of a charge-transfer state for the push-pull dyads. This work hence provides guidance for the rational design and optimization of innovative photosensitizers for image-guided photodynamic therapy.

Journal/Review: CHEMISTRY-A EUROPEAN JOURNAL

More Information: The authors thank the Research Foundation – Flanders (FWO) for financial support (projects G0D1521N and I006320N, the Scientific Research Community ’Supramolecular Chemistry and Materials’ (W002126N), and PhD scholarship NT – 1163923N). They also thank Hasselt University and the University of Namur for continuing finan cial support (BOF PhD scholarship MF-BOF20DOCNA01). The calculations were performed on the computers of the ’Consortium des equipements de Calcul Intensif (CECI)’ (https://www.ceci-hpc.be), including those of the ’UNamur Technological Platform of High-Performance Computing (PTCI)’ (https://www.ptci.unamur.be), for which we gratefully acknowledge financial support from the FNRSFRFC, the Walloon Region, and the University of Namur (Conventions no. 2.5020.11, GEQ U.G006.15, U.G018.19, 1610468, and RW/GEQ2016). NT, GS, and MDD acknowledge financial support from the European Union’s Horizon 2020 research and innovation program under Grant Agreement no. 871124 Laserlab-Europe. KVH thanks the Special Research Fund (BOF) – UGent (project BOF/24J/2023/084). The authors acknowledge Huguette Penxten for the cyclic voltammetry measurements.
KeyWords: Singlet Oxygen; Triplet Photosensitizers; Electron-transfer; State Formation; Kinetics; Design; Yields
DOI: 10.1002/chem.70986