Avance dmx 400 mhz instrument

All reagents and solvents were of reagent grade or purified according to standard methods before use. Analytical thin-layer chromatography (TLC) was performed with silica gel plates using silica gel 60 GF₂₅₄ (Qingdao Haiyang Chemical Co., Ltd., Qingdao, China). Melting points were determined on an XT-4 digital melting point apparatus (Beijing Tech Instrument Co., Ltd., Beijing, China) and were uncorrected. Proton nuclear magnetic resonance spectra (¹H NMR) were recorded on a Bruker Avance DMX 400 MHz instrument (Bruker, Bremerhaven, Germany) in CDCl₃ or DMSO-d₆ using TMS (tetramethylsilane) as the internal standard. Mass spectrometry (MS) was carried out with a Waters XEVO TQ-D instrument (Waters, Milford, MA, USA). High-resolution mass spectrometry (HRMS) was carried out with a Xevo G2-SQTOF instrument (Waters, Milford, MA, USA).

All ¹H and ¹³C NMR spectra were recorded on a Bruker AVANCE DMX 400 MHz instrument (Bruker, MA, USA) in CDCl₃. Chemical shift values were referenced to CHCl₃ at 7.26 ppm for ¹H NMR and 77.16 ppm for ¹³C NMR. Molecular weights and molecular weight distributions of the resultant copolymers were determined with a PL-GPC220 chromatograph (Polymer Laboratories, CA, USA) equipped with an HP 1100 pump (Agilent Technologies, CA, USA). The GPC columns were eluted with THF with 1.0 mL/min at 40 °C. The sample concentration was 0.4 wt%, and the injection volume was 50 μL. Calibration was performed using monodisperse polystyrene standards covering the molecular weight range from 500 to 5,000,000 Da.

All reagents and solvents were of reagent grade or were purified according to standard methods before use. Analytical thin-layer chromatography (TLC) was performed with silica gel plates using silica gel 60 GF₂₅₄ (Qingdao Haiyang Chemical Co., Ltd., Qingdao, China). Melting points were determined on an XT-4 digital melting point apparatus (Beijing Tech Instrument Co., Ltd., Beijing, China) and were uncorrected. Proton nuclear magnetic resonance spectra (¹H NMR) were recorded on a Bruker Avance DMX 400 MHz instrument (Bruker, Bremerhaven, Germany) in CDCl₃ or DMSO-d₆ using TMS (tetramethylsilane) as the internal standard. High-resolution mass spectrometry (HRMS) was carried out with a Xevo G2-SQTOF instrument (Waters, Milford, MA, USA).