U 4100 uv vis nir spectrometer

¹H NMR spectra were obtained on a Bruker Advance 400 spectrometer (Germany). FT-IR spectra were obtained on a TENSOR II FTIR routine spectrometer from Bruker (Germany) after pelleting samples with KBr. The UV-Vis absorption measurement was carried out on a Hitachi U-4100 UV/Vis/NIR spectrometer (Japan). Fluorescence spectra were performed on a FluoroMax-4 high efficiency integrated fluorescence spectrometer (Horiba. United States), and each measurement was repeated three times. The pH of the solution was measured by a Mettler Toledo SevenCompact pH meter S210. Confocal laser scanning microscopy (CLSM) images were recorded on a Leica TCS SP8 lighting confocal microscope (Germany).

¹ H NMR (300 or 400 MHz) and ¹³C NMR (100 MHz) spectra were recorded on a Bruker Avance 300 or 400 spectrometer using CDCl₃, DMSO-d₆ or D₂O as solvent and tetramethylsilane (TMS) as an internal standard. HR-MS spectra were recorded on a Q-TOF6510 spectrograph (Agilent). IR spectra were recorded by use of the IR spectrophotometer VERTEX 70 FT-IR (Bruker Optics). Melting points were measured on an XD-4 digital micro-melting point apparatus. Thin-layer chromatography (TLC) was conducted on silica gel 60F₂₅₄ plates (Merck KGaA) and column chromatography was conducted over silica gel (mesh 200–300). Fluorescence measurements were conducted on a Perkin-Elmer LS-55 luminescence spectrophotometer, and UV-vis spectra were recorded on a U-4100 UV-Vis-NIR Spectrometer (Hitachi). Quartz cuvettes with a 1 cm path length and 3-mL volume were involved in fluorescence and UV-vis absorption measurements. The pH values were measured by use of a PHS-3C digital pH-meter (YouKe, Shanghai). All reagents were purchased from J&K, Aladdin and Sinopharm Chemical Reagent Co. and used without further purification.