Water-Soluble Naphthalene Diimides as Singlet Oxygen Sensitizers

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• 作者：Filippo Doria ; Ilse Manet ; Vincenzo Grande ; Sandra Monti ; Mauro Freccero
• 刊名：The Journal of Organic Chemistry
• 出版年：2013
• 出版时间：August 16, 2013
• 年：2013
• 卷：78
• 期：16
• 页码：8065-8073
• 全文大小：480K
• 年卷期：v.78,no.16(August 16, 2013)
• ISSN：1520-6904

文摘

Bromo- and/or alkylamino-substituted and hydrosoluble naphthalene diimides (NDIs) were synthesized to study their multimodal photophysical and photochemical properties. Bromine-containing NDIs (i.e., 11) behaved as both singlet oxygen (¹O₂) photosensitizers and fluorescent molecules upon irradiation at 532 nm. Among the NDIs not containing Br, only 12 exhibited photophysical properties similar to those of Br-NDIs, by irradiation above 610 nm, suggesting that for these NDIs both singlet and triplet excited-state properties are strongly affected by length, structure of the solubilizing moieties, and pH of the solution. Laser flash photolysis confirmed that the NDI lowest triplet excited state was efficiently populated, upon excitation at both 355 and 532 nm, and that free amine moieties quenched both the singlet and triplet excited states by intramolecular electron transfer, with generation of detectable radical anions. Time-resolved experiments, monitoring the 1270 nm ¹O₂ phosphorescence decay generated upon laser irradiation at 532 nm, allowed a ranking of the NDIs as sensitizers, based on their ¹O₂ quantum yields (桅_螖). The tetrafunctionalized 12, exhibiting a long-lived triplet state (蟿 32 渭s) and the most promising absorptivity for photodynamic therapy application, was tested as efficient photosensitizers in the photo-oxidations of 1,5-dihydroxynaphthalene and 9,10-anthracenedipropionic acid in acetonitrile and water.