Design of a Water Soluble Fluorescent 3-Hydroxy-4-Pyridinone Ligand Active at Physiological pH Values

• Type: Article in International Scientific Journal
• Date: 2016

Authors

Leite, A (Author) Other; Silva, AMG (Author) Other; Coutinho, C (Author) Other; Cunha Silva, L (Author) FCUP; de Castro, B (Author) FCUP; Maria Rangel (Author) ICBAS

Journal

Title: Journal of Fluorescence

Vol. 26

Pages: 1773-1785

ISSN: 1053-0509

Publisher: Springer Nature

Indexing

ISI Web of Knowledge - 3 Citations

Scopus - 3 Citations

Other information

Authenticus ID: P-00K-KT6

DOI: 10.1007/s10895-016-1869-1

Abstract (EN): In the present work we report the structure and the spectroscopic characterization of a new fluorescent 3-hydroxy-4-pyridinone ligand D-3,4-HPO. The synthesis of the compound was performed in two steps, which involve the reaction of the commercially available fluorophore dansyl chloride with a 3-hydroxy-4-pyridinone chelating unit and further deprotection. The new fluorescent chelator was characterized in the solid state by single-crystal X-ray diffraction and in solution by NMR, MS, absorption and fluorescence spectroscopies. The analysis of the variation of the absorption spectrum with pH allowed the determination of four pK (a) values (pK (a1) = 3.50, pK (a2) = 4.50, pK (a3) = 9.60, pK (a4) = 10.20) and establishment of the corresponding distribution diagram. The study of the fluorescence properties of the ligand show that in the pH range between 4 and 9 the fluorescence intensity is constant and has its maximum value thus allowing its further use at physiological pH values. The interaction of the ligand with copper(II) was accessed by fluorescence spectroscopy in MOPS buffer and the results show that the presence of copper(II) quenches the fluorescence of the ligand in ca 94 % at a ligand: metal ratio of 2:1. The latter result is consistent with the formation of a copper(II) complex with the bidentate ligand, as confirmed by the EPR spectroscopy.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 13