Am 300 spectrometer

NMR spectra were measured using a Bruker AM300 spectrometer (Bruker Biospin GMBH, Rheinstetten, Germany) at 300 MHz for ¹H and 75.45MHz for ¹³C. Column chromatography was performed on neutral alumina or silica. Electrochemical measurements were performed on a CHI660C potentiostat (CH Instruments Company, Austin, TX, USA). The ligand and electrolyte (Bu₄NPF₆ or Bu₄NB(C₆F₅)₄) concentrations were typically 0.001, 0.1, and 0.05 mol·dm⁻³. A three-electrode one-compartment cell was used, including 500-µm-diameter platinum-disc working electrodes, a platinum wire counter electrode, and an Ag|Ag⁺ reference electrode.

The purity of Q3G was checked by Agilent 1260 HPLC–DAD on a Zorbax Eclipse Plus C18 column (2.1 × 150 mm, 3.5 μm). Elution conditions were as follows: 0.4 ml/min flow rate; 35 °C; solvent A, water/formic acid (99.9: 0.1 v/v); solvent B, acetonitrile (100%); isocratic elution of 11% B for 30 min, followed by washing and re-equilibration of the column. Qualitative analysis of Q3G was performed by an Agilent 6530 Q-TOF/MS system (Agilent Technologies, USA) equipped with an electrospray ionization (ESI) source. ¹H, ¹³C-NMR, HMBC and HSQC data of Q3G (TMS as internal standard) were recorded in CD3OD on a Bruker AM-300 spectrometer at 300 MHz.

The yield of obtained biomasses is identified by Equation (1):
where W_t and W₀ are the weight of obtained biomass and original product, respectively.
The purity of obtained biomasses is identified by Equation (2) via Area Normalization method:
where A_m and A_n are the peak area of analyte and the total area of all peaks, respectively.
¹H NMR and ¹³C NMR spectra were recorded on Bruker AM-300 spectrometer operating at 300 MHz and Bruker AM-400 spectrometer at 400 MHz, respectively. Fourier transmission infrared (FTIR) measurements were performed by a Nicolet MAGNA-550 FTIR (Nicolet Instrument Co., Madison, WI) at room temperature. The samples were dried and pressed in a KBr pellet. UV-vis spectra were carried out on a UV-2550 spectrophotometer (Beijing Sartorius Co., Ltd., China). The fluorescence spectra were conducted on a Hitachi F-4500 fluorescence spectrophotometer (Hitachi, Ltd., Tokyo, Japan). High-performance liquid chromatography (HPLC) analysis was carried out on Waters Alliance HPLC system, assembled by Waters 600 controller, Waters 600 pump, and Waters 2996 photodiode array detector (Waters, Milford, MA, USA). The chromatographic separation was performed by injecting a 5 μL sample volume on a C18 column (4.8 × 150 mm, 5 μm particle size).

¹H-NMR spectra was recorded from CDCl₃ solution on a Bruker AM 300 spectrometer. Column chromatography (silica gel 100–200) was used to check the purity of the products. A Perkin Elmer Pyris Diamond differential scanning calorimeter (Perkin Elmer, Waltham, MA, USA) was used to determine the thermal transitions with the maxima and minima of their endothermic or exothermic peaks, controlling the heating and cooling rates to 10 °C/min. X-ray scattering measurements were performed in transmission mode with synchrotron radiation at the 1W2A X-ray beam line at Beijing Accelerator Laboratory (Beijing, China). MALDI-TOF-MS was performed on a Perceptive Biosystems Voyager-DE STR (Applied Biosystems, Foster City, CA, USA) using a 2-cyano-3-(4-hydroxyphenyl) acrylic acid (CHCA) as matrix.