EXCITED STATE ABSORPTION-BASED PHOTOCHEMISTRY IN MESO-TETRA(4-PYRIDYL) ZINC PORPHYRIN

Jefferson Marcio Sanches Lopes; Alzir Azevedo Batista; Paulo T. Araújo; UA; Newton Martins Barbosa Neto

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Submission

Paper Title

EXCITED STATE ABSORPTION-BASED PHOTOCHEMISTRY IN MESO-TETRA(4-PYRIDYL) ZINC PORPHYRIN

Authors

Jefferson Marcio Sanches Lopes
Alzir Azevedo Batista
Paulo T. Araújo; UA
Newton Martins Barbosa Neto

Modality

Pôster

Subject area

Síntese e caracterização de materiais

Publishing Date

12/12/2023

Country of Publishing

Brasil

Language of Publishing

Inglês

Paper Page

https://www.even3.com.br/anais/workshop-do-ineo-2023/612336-excited-state-absorption-based-photochemistry-in-meso-tetra(4-pyridyl)-zinc-porphyrin

ISBN

978-65-272-0088-8

Keywords

Porphyrin, Metalloporphyrin, Photochemistry, Excited-State Absorption, Optical Spectroscopy

Summary

Excited state absorption (ESA) stands as a selective, and noninvasive excitation mechanism for the photochemical modification of porphyrin structures. Our group has recently explored the use of ESA to controllably photo-protonate and photo-aggregate pyridyl- and phenyl-substituted free-base porphyrins in chloroform [1,2,3]. This is possible because ESA operating in the visible can replace the UV excitation of porphyrins, enabling the molecules to access high-energy excited states capable of triggering the decomposition of chlorinated solvents through an oxi-reduction reaction, which finally leads to the release of protons in solution and favors the modification of the macrocycle and its outlying ligands [1,2,3]. In the present work, we investigated ESA-driven photochemical reactions in a metalloporphyrin model (the meso-tetra(4-pyridyl) zinc (II) porphyrin (ZnTPyP)) dissolved in the chloroform: methanol (9:1 v/v) binary solvent. By means of steady-state and time-resolved optical spectroscopy techniques, it is observed that the initial solution evolves into a complex molecular system after pulsed irradiation. Three distinct types of ESA-driven photoproducts are verified, being the first specie assigned to the photo-protonation of the outlying meso-substituents of ZnTPyP; the second to the possible photolysis of ZnTPyP, and the third to the formation of a ground-state complex between photolyzed and remnant unmodified ZnTPyP molecules. The data also suggest the occurrence of Forster resonance energy transfer between remnant ZnTPyP and the formed complex. Finally, optimal conditions for these ESA-based photochemical reactions are addressed, where it is found that solvent, critical concentration, and irradiation conditions play key roles in the observed results. The work was funded by CNPq, CAPES, FAPESPA e INEO. [1] J. M. S. Lopes, A. E. H. Machado, A. A. Batista, P. T. Araujo and N. M. Barbosa Neto, Protonation, exciplex, and evidence of aggregate formation in meso-tetra(4-pyridyl) porphyrin triggered by excited-state absorption, J. Photochem. Photobiol., A, 426, (2022), 113759. [2] J. M. S. Lopes, A. E. H. Machado, A. A. Batista, B. A. Iglesias, P. T. Araujo and N. M. Barbosa Neto, Fluorinated phenyl meso-substituents regulating excited state absorption-driven protonation of free-base porphyrins, J. Photochem. Photobiol., A: 438, (2023) 114568. [3] J. M. S. Lopes, A. A Batista, P. T. Araujo, N. M. Barbosa Neto, Supramolecular porphyrin as an improved photocatalyst for chloroform decomposition, RSC Adv., 13, (2023), 5473.

Title of the Event: Workshop do INEO 2023
City of the Event: Nazaré Paulista
Title of the Proceedings of the event: Anais do Workshop INEO 2023
Name of the Publisher: Even3
Means of Dissemination: Meio Digital

How to cite

LOPES, Jefferson Marcio Sanches et al.. EXCITED STATE ABSORPTION-BASED PHOTOCHEMISTRY IN MESO-TETRA(4-PYRIDYL) ZINC PORPHYRIN.. In: Anais do workshop INEO 2023. Anais...Nazaré Paulista(SP) Hotel Estância Atibainha, 2023. Available in: https//www.even3.com.br/anais/workshop-do-ineo-2023/612336-EXCITED-STATE-ABSORPTION-BASED-PHOTOCHEMISTRY-IN-MESO-TETRA(4-PYRIDYL)-ZINC-PORPHYRIN. Access in: 26/12/2024