Bright NIR-Emitting Styryl Pyridinium Dyes with Large Stokes’ Shift for Sensing Applications

作者：Nirasha I. Wickramasinghe, Brian Corbin, Devni Y. Kanakarathna, Yi Pang, Chathura S. Abeywickrama, Kaveesha J. Wijesinghe · 发表于：Biosensors · 年份：2023 · DOI：10.3390/bios13080799 · 被引用次数：24 · 研究领域：Luminescence and Fluorescent Materials、Photochemistry and Electron Transfer Studies、Photodynamic Therapy Research Studies

Two NIR-emitting donor-π-acceptor (D-π-A) type regioisomeric styryl pyridinium dyes (1a–1b) were synthesized and studied for their photophysical performance and environment sensitivity. The two regioisomers, 1a and 1b, exhibited interesting photophysical properties including, longer wavelength excitation (λex ≈ 530–560 nm), bright near-infrared emission (λem ≈ 690–720 nm), high-fluorescence quantum yields (ϕfl ≈ 0.24–0.72) large Stokes’ shift (∆λ ≈ 150–240 nm) and high-environmental sensitivity. Probe’s photophysical properties were studied in different environmental conditions such as polarity, viscosity, temperature, and concentration. Probes (1a–1b) exhibited noticeable changes in absorbance, emission and Stokes’ shift while responding to the changes in physical environment. Probe 1b exhibited a significant bathochromic shift in optical spectra (∆λ ≈ 20–40 nm) compared to its isomer 1a, due to the regio-effect. Probes (1a–1b) exhibited an excellent ability to visualize bacteria (Bacillus megaterium, Escherichia coli), and yeast (Saccharomyces cerevisiae) via fluorescence microscopy.