Avance 3 400 m nmr spectrometer

The molecular structures of urea, melamine, EUMF-1, and EUMF-4 were characterized by Fourier transform infrared (FT-IR) and ¹³C NMR spectroscopy. The FT-IR spectra of the samples were recorded on a Nicolet 6700 spectrometer in the range of 400–4000 cm⁻¹ at a scan number of 32 and a resolution of 4 cm⁻¹, and the ¹³C NMR spectra were recorded on a Bruker Avance III 400 M NMR spectrometer (Buchi, Switzerland) with a relaxation delay of 5 s. The samples were prepared by dissolving approximately 50–60 mg of product in 0.5 mL of deuterated dimethyl sulfoxide (DMSO-D6).

The morphology of the MMIPs was analyzed by a scanning electron microscope (SEM) (FEI, Nova NanoSEM 450, Hillsboro, OR, USA) in secondary electron mode, with an acceleration voltage of 10 kV. The samples were coated with a thin film of gold to enable SEM imaging. The magnetic properties (saturation magnetization and coercivity) were measured using a Lakeshore 7407 vibrating sample magnetometer. X-ray powder diffraction (XRPD) patterns were collected with a PANalytical Empyrean diffractometer using monochromatic Cu Kα radiation (λ = 0.154 nm). The applied voltage and current were set to 45 kV and 40 mA, respectively. The pattern was scanned over a 2θ angle range from 20° to 70°. FT-IR spectroscopy was measured using a thermo Nicolet iS10 FT-IR spectrometer. ¹H NMR and ¹³C NMR spectra were obtained from a Bruker Avance III-400M NMR spectrometer with D₂O as the solvent. Thermo-gravimetric analysis (TGA) was carried out using a Q5000 thermogravimetric analyzer (TA Instruments, New Castle, DE, USA) over a temperature range of 30–700 °C. The scan rate was set to 10 °C·min⁻¹ with dry nitrogen gas.