Alkynyl-naphthalimide Fluorophores: Gold Coordination Chemistry and Cellular Imaging Applications

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• 作者：Emily E. Langdon-Jones ; David Lloyd ; Anthony J. Hayes ; Shane D. Wainwright ; Huw J. Mottram ; Simon J. Coles ; Peter N. Horton ; Simon J. A. Pope
• 刊名：Inorganic Chemistry
• 出版年：2015
• 出版时间：July 6, 2015
• 年：2015
• 卷：54
• 期：13
• 页码：6606-6615
• 全文大小：487K
• ISSN：1520-510X

文摘

A range of fluorescent alkynyl-naphthalimide fluorophores has been synthesized and their photophysical properties examined. The fluorescent ligands are based upon a 4-substituted 1,8-naphthalimide core and incorporate structural variations (at the 4-position) to tune the amphiphilic character: chloro (L1), 4-[2-(2-aminoethoxy)ethanol] (L2), 4-[2-(2-methoxyethoxy)ethylamino] (L3), piperidine (L4), morpholine (L5), 4-methylpiperidine (L6), and 4-piperidone ethylene ketal (L7) variants. The amino-substituted species (L2鈥?b>L7) are fluorescent in the visible region at around 517鈥?35 nm through a naphthalimide-localized intramolecular charge transfer (ICT), with appreciable Stokes鈥?shifts of ca. 6500 cm^鈥? and lifetimes up to 10.4 ns. Corresponding two-coordinate Au(I) complexes [Au(L)(PPh₃)] were isolated, with X-ray structural studies revealing the expected coordination mode via the alkyne donor. The Au(I) complexes retain the visible fluorescence associated with the coordinated alkynyl-naphthalimide ligand. The ligands and complexes were investigated for their cytotoxicity across a range of cell lines (LOVO, MCF-7, A549, PC3, HEK) and their potential as cell imaging agents for HEK (human embryonic kidney) cells and Spironucleus vortens using confocal fluorescence microscopy. The images reveal that these fluorophores are highly compatible with fluorescence microscopy and show some clear intracellular localization patterns that are dependent upon the specific nature of the naphthalimide substituent.