Microwave-assisted synthesis of 3-hydroxy-4-pyridinone/naphthalene conjugates. Structural characterization and selection of a fluorescent ion sensor

• Type: Article in International Scientific Journal
• Date: 2010

Authors

Ana M G Silva (Author) Other; Andreia Leite (Author) Other; Mariana Andrade (Author) Other; Paula Gameiro (Author) FCUP; Paula Brandao (Author) Other; Vitor Felix (Author) Other; Baltazar de Castro (Author) FCUP; Maria Rangel (Author) ICBAS

Journal

Title: Tetrahedron

Vol. 66 No. 34

Pages: 8544-8550

ISSN: 0040-4020

Publisher: Elsevier

Indexing

ISI Web of Knowledge - 24 Citations

Scopus - 25 Citations

Scientific classification

FOS: Natural sciences > Chemical sciences

Other information

Authenticus ID: P-003-1SS

DOI: 10.1016/j.tet.2010.08.065

Abstract (EN): Two novel 3-hydroxy-4-pyridinone/naphthalene conjugates (L1 and L2) with different distances between the chelating and the fluorescent moieties were synthesized using conventional heating and microwave irradiation achieving a shorter reaction time. The structure of both compounds was confirmed by X-ray crystallography, revealing that these compounds were isolated as hydrochloride salts in dihydroxypyridinium forms. In solution and in the presence of a base, the tautomeric keto forms may be obtained as it was elucidated by NMR analysis. The dihydroxypyridinium form of L1 exhibits fluorescence at 450 nm, both in ACN and DMSO, whereas the corresponding keto form exhibits fluorescence at 365 nm. In contrast, the dihydroxypyridinium form of L2 only fluoresces in DMSO, exhibiting a band at 340 nm, while the keto form is non-fluorescent. These distinct fluorescent behaviors reveal that the tautomeric form in which the ligands are isolated and the distance between the chelating and fluorescent functions strongly influences their fluorescence properties. Ligand L1 exhibits better fluorescence properties and its fluorescence intensity is quenched in the presence of variable concentration of Cu(2+), Zn(2+), and Fe(3+), thus making it suitable to be used as ion sensor.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 7