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A porphyrin molecule that generates, traps, stores, and releases singlet oxygen

Paper ID Volume ID Publish Year Pages File Format Full-Text
26550 43962 2013 5 PDF Available
Title
A porphyrin molecule that generates, traps, stores, and releases singlet oxygen
Abstract

•Preparation of a composite molecule that has four 2-pyridone moieties bonded directly to a porphyrin photosensitizer dye.•These materials have the capacity to generate, store, and release singlet oxygen.•Oxidation of the mustard gas simulant, 2-chloroethyl ethyl sulfide (CEES), by singlet oxygen released in the dark from the sensitizer-storage molecule is demonstrated.

Tetraphenylporphyrin (H2TPP), covalently linked to four 2-pyridone moieties was synthesized (II) and studied. This composite molecule, in combination with light and ground state oxygen, has the ability to generate, trap, store, and release singlet oxygen. The process can be operated reversibly without detectable decomposition or side reactions using light with wavelength greater than 500 nm. Oxidation of the target molecule, 2-chloroethyl ethyl sulfide (CEES), by singlet oxygen released from the endoperoxide of the porphyrin-2-pyridone molecule (I) is demonstrated. Spectroscopic and kinetic data do not reveal evidence of perturbation between the porphyrin and pyridone ring systems of II. The decomposition kinetics for the endoperoxide adduct I are first order with activation parameters ΔH‡ = 26.7 (kcal/mol) and ΔG‡ = 24.0 (kcal/mol). Experimental and computational studies of unattached N-benzyl-2-pyridone peroxide are reported and compared to the experimental data for I.

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Keywords
Singlet oxygen; Photosensitizer; Porphyrin
First Page Preview
A porphyrin molecule that generates, traps, stores, and releases singlet oxygen
Publisher
Database: Elsevier - ScienceDirect
Journal: Journal of Photochemistry and Photobiology A: Chemistry - Volume 260, 15 May 2013, Pages 9–13
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering