New application of fluorescent organotin compounds derived from Schiff bases: synthesis, X-ray structures, photophysical properties, cytotoxicity and fluorescent bioimaging

Abstract

A series of eight new organotin compounds derived from Schiff bases has been prepared by a multicomponent reaction from 2-hydroxy-1-naphthaldehyde or 4-substituted-2-hydroxybenzalhedyde, benzhydrazine, and the corresponding diorganotin oxide (R₂SnO, R = ⁿBu or Ph). All of the compounds were fully characterized by NMR (¹H, ¹³C, and ¹¹⁹Sn), IR, UV/vis, elemental analyses and fluorescence spectroscopy. The crystal structures for some organotin compounds were determined by single crystal X-ray diffraction analysis. All of the compounds display fluorescence at room temperature with quantum yields of about 2 × 10^-4 to 0.56. The cytotoxic activity and cellular imaging studies were carried out with the newly synthesized compounds. To the best of our knowledge, this is the first report of organotin compounds with Schiff base ligands investigated for fluorescence bioimaging (FBI).