Basis for sensitive and selective time-delayed luminescence detection of hydroxyl radical by lanthanide complexes
| Autor: | Katie L. Peterson, Valérie C. Pierre, Maximilian J. Margherio, Phi Doan, Kyle T. Wilke |
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| Rok vydání: | 2013 |
| Předmět: |
Lanthanide
Aromatic acid Time Factors Molecular Structure Hydroxyl Radical chemistry.chemical_element Terbium Photochemistry Lanthanoid Series Elements Article Inorganic Chemistry Hydroxylation chemistry.chemical_compound Acetic acid chemistry Amide Luminescent Measurements Organometallic Compounds Hydroxyl radical Physical and Theoretical Chemistry Luminescence |
| Zdroj: | Inorganic chemistry. 52(16) |
| ISSN: | 1520-510X |
| Popis: | Molecular probes for the detection of hydroxyl radical (HO•) by time-delayed luminescence spectroscopy directly in water at neutral pH with high sensitivity and selectivity are presented. The bimolecular probes consist of a lanthanide complex with open coordination sites and a reactive pre-antenna composed of an aromatic acid or amide; the latter binds to and sensitizes terbium emission upon hydroxylation by HO•. These probes exhibit long luminescence lifetimes compatible with time-delayed measurements that remove interfering background fluorescence from the sample. Six different reactive pre-antenna (benzoate, benzamide, isophthalate, isophthalamide, trimesate, and trimesamide) and two different terbium complexes [Tb-(1,4,7,10-tetraazacyclododecane-1,4,7-tris(acetic acid)) (Tb-DO3A) and Tb-(1,4,7,10-tetraazacyclododecane-1,7-bis(acetic acid)) (Tb-DO2A)] were evaluated. Of these the trimesamide/Tb-DO3A system enables the most sensitive detection of HO• with an about 1000-fold increase in metal-centered time-delayed emission upon hydroxylation of the pre-antenna to 2-hydroxytrimesamide. Excellent selectivity for both the trimesamide/Tb-DO3A and trimesate/Tb-DO3A systems over other reactive oxygen and nitrogen species are observed. Notably, the increase in metal-centered luminescence intensity is not associated with a decrease in the hydration number (q) of Tb-DO3A, suggesting that the antenna is interacting with the lanthanide via a second sphere coordination environment or that coordination by the antenna occurs by displacement of one or more of the carboxylate arms of DO3A. Formation of a weak ternary complex Tb-DO3A•hydroxytrimesamide was confirmed by temperature-dependent titration and a decrease in K(app) with increasing temperature. |
| Databáze: | OpenAIRE |
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