Organoboron Schiff bases as cell‐staining fluorescent probes: Synthesis, Chemio‐photophysical characterization, DFT, and X‐ray structures

Abstract

The fluorescence imaging technologies are becoming the most powerful and noninvasive diagnostic tools in cellular biology and modern medicine where abnormal cell arrangements are associated with diseases. Thus, these techniques require new fluorescent dyes with excellent chemical, physical, and photophysical properties. A series of four new Boron Schiff bases ( 1 – 4 ) has been prepared by condensation between phenylboronic acid with the corresponding ligand. The compounds were characterized by NMR ( 1 H, 13 C, and 11 B), U V / v is, fluorescence spectroscopy, and high‐resolution mass spectrometry. The crystal structures of three compounds showed tetracoordinated Boron atoms with semiplanar skeleton ligands. Interesting organoboron response to viscosity on their fluorescence (Φ: more than 3‐fold). Additionally, compounds 1 and 2 were found to serve as a fluorescent dye for cell imaging (B16F10, CaCo, and A‐431 cells) since it has the capability to rapidly accumulate within the cells and gave bright green fluorescence, it showed low cytotoxicity activity and high photostability in solution. Additionally, the compounds have also been investigated using DFT.