Probing Triplet Photochemistry in Ru(II) Porphyrins Using Singlet Oxygen Generation and Triplet–Triplet Annihilation Upconversion
7 affiliations
- 1SPIN-Lab Centre for Microscopic Research on Matter, University of Silesia in Katowice, 75 Pulku Piechoty 1A, Chorzow 41-500, Poland
- 2Institute of Chemistry, University of Silesia in Katowice, Szkolna 9, 40-006 Katowice, Poland
- 3Faculty of Chemistry, Silesian University of Technology, Strzody 9, 44-100 Gliwice, Poland
- 4Centre for Organic and Nanohybrid Electronics, Silesian University of Technology, Konarskiego 22b, 44-100 Gliwice, Poland
- 5Department of Physics, Durham University, South Road, Durham DH1 3LE, U.K.
- 6Department of Materials Science and Metallurgy, University of Cambridge, Cambridge CB3 0FS, U.K.
- 7Department of Chemistry, Federal University of Santa Catarina, 88040-900 Florianópolis, Santa Catarina, Brazil
Abstract
Porphyrins are known for their rich triplet-state photophysics, making them attractive platforms for light-driven applications. Compared with extensively studied Pd(II) and Pt(II) porphyrins, Ru(II) porphyrins remain less systematically explored, particularly for triplet-driven reactivity. Here, we demonstrate that a single porphyrin framework can perform complementary functions: generate singlet oxygen (1O2) and photosensitize triplet–triplet annihilation upconversion (TTA-UC). We examine six related systems: free-base porphyrins (1A/1B) and Ru(II) complexes 2A/2B with CO and 3A/3B with CO plus PyPX (10-(pyridin-4-yl)-10H-phenoxazine). Complexes 3A and 3B are newly synthesized Ru(II) porphyrins, enabling direct assessment of axial ligation effects within this series. Optical spectroscopy, DFT/TD-DFT calculations, 1O2 measurements, and TTA-UC experiments investigate how metalation, bromination, and axial ligation influence triplet-state properties. Ru(II) insertion promotes intersystem crossing, leading to 1O2 quantum yields up to 70%. Bromination further increases Φ Δ in the free-base and monoaxial complexes. In contrast, PyPX coordination significantly increases Φ Δ in the nonbrominated system (2A to 3A) but has negligible influence in the brominated analogue (2B to 3B). Complexes 3A/3B also sensitize TTA-UC, achieving efficiencies of ∼1.3–1.4% with perylene in THF. Collectively, our results establish design principles for Ru(II) porphyrins as triplet sensitizers, enabling control over complementary triplet-driven photochemical processes within a single molecular platform.
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BibTeX
@article{nyga2026probing,
title = {{Probing Triplet Photochemistry in Ru(II) Porphyrins Using Singlet Oxygen Generation and Triplet–Triplet Annihilation Upconversion}},
author = {Aleksandra Nyga and Marli Ferreira and Piotr Pander and Ivan Gusev and Larissa Gomes Franca and Georgina H. Burgoyne Morris and Martyna Jankowska and Priscila Pazini Abatti and Karol Erfurt and Rachel C. Evans and Agata Blacha-Grzechnik},
journal = {Inorganic Chemistry},
year = {2026},
month = oct,
doi = {10.1021/acs.inorgchem.6c03345},
url = {https://doi.org/10.1021/acs.inorgchem.6c03345},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Probing Triplet Photochemistry in Ru(II) Porphyrins Using Singlet Oxygen Generation and Triplet–Triplet Annihilation Upconversion
AU - Aleksandra Nyga
AU - Marli Ferreira
AU - Piotr Pander
AU - Ivan Gusev
AU - Larissa Gomes Franca
AU - Georgina H. Burgoyne Morris
AU - Martyna Jankowska
AU - Priscila Pazini Abatti
AU - Karol Erfurt
AU - Rachel C. Evans
AU - Agata Blacha-Grzechnik
PY - 2026
DA - 2026/10/11
JO - Inorganic Chemistry
DO - 10.1021/acs.inorgchem.6c03345
UR - https://doi.org/10.1021/acs.inorgchem.6c03345
AB - Porphyrins are known for their rich triplet-state photophysics, making them attractive platforms for light-driven applications. Compared with extensively studied Pd(II) and Pt(II) porphyrins, Ru(II) porphyrins remain less systematically explored, particularly for triplet-driven reactivity. Here, we demonstrate that a single porphyrin framework can perform complementary functions: generate singlet oxygen (1O2) and photosensitize triplet–triplet annihilation upconversion (TTA-UC). We examine six related systems: free-base porphyrins (1A/1B) and Ru(II) complexes 2A/2B with CO and 3A/3B with CO plus PyPX (10-(pyridin-4-yl)-10H-phenoxazine). Complexes 3A and 3B are newly synthesized Ru(II) porphyrins, enabling direct assessment of axial ligation effects within this series. Optical spectroscopy, DFT/TD-DFT calculations, 1O2 measurements, and TTA-UC experiments investigate how metalation, bromination, and axial ligation influence triplet-state properties. Ru(II) insertion promotes intersystem crossing, leading to 1O2 quantum yields up to 70%. Bromination further increases Φ Δ in the free-base and monoaxial complexes. In contrast, PyPX coordination significantly increases Φ Δ in the nonbrominated system (2A to 3A) but has negligible influence in the brominated analogue (2B to 3B). Complexes 3A/3B also sensitize TTA-UC, achieving efficiencies of ∼1.3–1.4% with perylene in THF. Collectively, our results establish design principles for Ru(II) porphyrins as triplet sensitizers, enabling control over complementary triplet-driven photochemical processes within a single molecular platform.
SN - 0020-1669
SN - 1520-510X
ER -