Naphthalimide-BODIPY dyads: Synthesis, characterization, photophysical properties, live cell imaging and antimicrobial effect

Naphthalimide-Borondipyrromethene (NI-BODIPY) dyads, bearing NI unit on the meso and styryl positions of BODIPY core were designed and subjected to photophysical, in vitro cell imagining and antimicrobial activity studies. The identities of synthesized compounds ( 3 - 5 ) were confirmed by using FT-IR, 1 H, 13 C NMR and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. The structure of the NI-BODIPY dyad ( 3 ) was also characterized by means of X-ray diffraction. Spectroscopic properties of dyad systems were explored in detail via UV-vis absorption and fluorescence emission spectroscopies. Mono- and distyryl- derivatives ( 4 and 5 ) revealed a substantial conjugation effect manifested by an expected bathochromic shift in absorption and emission spectra relative to dyad 3 . The use of NI-BODIPYs for live cell lines is demonstrated by flow cytometry and confocal microscopy in which compound 3 produced the brightest fluorescence in confocal microscopy. Furthermore in vitro antimicrobial activities were evaluated on Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli . Noticeably, the distyryl- derivative 5 functionalized with three NI units displayed superior antibacterial activity against both E. coli and S. aureus with MIC values of 76 and 110 mu M, respectively. Naphthalimide decorated BODIPY dyads have been proposed as both antibacterial and cell imaging agents.(c) 2022 Elsevier B.V. All rights reserved.