Mandić, Leo; Džeba, Iva; Jadreško, Dijana; Mihaljević, Branka; Biczók, László; Basarić, Nikola (2020) Photophysical properties and electron transfer photochemical reactivity of substituted phthalimides. New Journal of Chemistry, 44 . pp. 17252-17266. ISSN 1144-0546
Abstract
Photochemical reactivity, photophysical and electrochemical properties for a series of N-adamantylphthalimides bearing carboxylic functional groups were investigated. Upon irradiations (with or without a triplet sensitizer), compounds undergo decarboxylation via a photoinduced electron transfer (PET) from the carboxylate to the phthalimide. UV-Vis and fluorescence pH titrations were used to determine pKa values for the prototropic forms, which were put in connection with quantum yields of the reaction (ΦR). Compounds bearing electron donors OH and OCH3 at the phthalimide 4 position are fluorescent (ΦF = 0.02-0.49) and PET takes place from both singlet and triplet excited states. Estimated rate constants for PET in the singlet excited states for methoxy- and amino-substituted phthalimides are (2.0 ± 0.1) × 10^9 s-1and (3.4 ± 1.0) × 10^7 s-1, respectively. Laser flash photolysis (LFP) was conducted to characterize triplet excited states, which are populated less efficiently for compounds with electron donors. The PET is reversible and the overall ΦR depends on the rates for back electron transfer, protonation of the phthalimide radical anion and decarboxylation. Plausible photochemical and photophysical pathways depend on the phthalimide substituents, which is important for the use of phthalimide derivatives in organic synthesis and photocatalysis.
| Item Type: | Article | ||||||||
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| Uncontrolled Keywords: | phthalimides; photodecarboxylation; photoinduced electron transfer; photophysics | ||||||||
| Subjects: | NATURAL SCIENCES > Chemistry NATURAL SCIENCES > Chemistry > Organic Chemistry |
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| Divisions: | Division for Marine and Enviromental Research Division of Materials Chemistry Division of Organic Chemistry and Biochemistry |
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| Depositing User: | Leo Mandić | ||||||||
| Date Deposited: | 17 Nov 2021 08:33 | ||||||||
| URI: | http://fulir.irb.hr/id/eprint/6728 | ||||||||
| DOI: | 10.1039/D0NJ03465G |
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