Esi tof ms system

All chemicals for synthesis were purchased from Acros Organics and Sigma-Aldrich and used as received. Molecular biology-grade reagents for cell culture and fluorescent confocal microscopy experiments were purchased from Thermo Fisher. NMR characterization data were acquired on a Bruker 400 MHz NMR spectrometer. High-resolution mass spectrometric data were acquired using an ESI-TOF MS system (Waters, Milford, MA, USA). UV-vis studies were carried out in a Hewlett Packard-8453 diode array spectrophotometer at 25 °C. Fluorescence studies were conducted in a HORIBA Fluoromax-4 spectrofluorometer. Fluorescence confocal microscopy imaging was performed by a Nikon A1 confocal system with 100x oil objectives, a numerical aperture of 1.45, and a refractive index of 1.5. Throughout imaging, the temperature was maintained at 37 °C. Probes 3a–3b were synthesized according to the previously reported procedure [35 (link)].

All starting materials and the essential solvents were purchased from Sigma-Aldrich, TGI, Ark Pharma, Fischer Scientific, Alfa-Asaer and Across Organics and directly used without further purification. Starting materials 2-(Benzo[d]thiazol-2-yl)-4-methylphenol (8) and 2-(benzo[d]oxazol-2-yl)-4-methylphenol (10) were synthesized by using literature procedures. All deuterated solvents were purchased from Cambridge Isotopes and used as received. All NMR data were recorded on Varian 300 and 500 MHz instruments with all spectra referenced to deuterated solvents. HRMS data were acquired on an ESI-TOF MS system (Waters, Milford, MA). UV−vis studies were carried out in Hewlett-Packard-8453 diode array-based spectrophotometer at 25 °C. Fluorescence spectral analysis was conducted by using a HORIBA Fluoromax-4 spectrofluorometer.
Fluorescence lifetime was measured by using a time-correlated single-photon counting (TCSPC) method, on a Horiba DeltaPro lifetime system, which is capable of measuring a lifetime range of 30 ps-1 s. The instrument is equipped with a picosecond photon detection module comprising a fast, cooled, photomultiplier with 230–850nm response. All measurements were performed by exciting the sample solutions with a Horiba DeltaDiode^TM DD-405 Laser (peak wavelength at 405 nm +/−10 nm).