Avance spectrometer

Polyvinylidene fluoride (PVDF) (MW ~530,000) and Dimethylformamide (DMF) were purchased from Merck; Vulcan XC72 Carbon Black (CB) was used, and 0.05 mm thick conductive graphite paper (RERAS, purchased from China and used as electrode substrate) was used to prepare cathode materials.
Melting points were measured on a Kruess KSP 11 Melting Point Analyzer. ¹H NMR spectra were recorded on a Brucker Avance spectrometer at 300 or 500, respectively, in DMSO-d₆ or CDCl₃ solutions. Chemical shifts were expressed in parts per million (δ, ppm) relative to solvent signal (DMSO-d₆: 2.50 ppm CDCl₃: 7.26 ppm for ¹H NMR) [46 (link)]. Compounds 3a–g are too insoluble to record a qualitative ¹³C NMR spectrum. Elemental CHN analysis was carried out on a Euro Vector EA 3000 analyzer. FTIR spectra were recorded on a Perkin-Elmer Spectrum 100 FTIR spectrometer. The UV–Vis absorption spectra were acquired with a Perkin-Elmer 35 UV/Vis spectrometer using 1 cm length quartz cuvettes with a concentration of compound c = 2.5 × 10⁻⁵ M. Low-resolution mass spectra were acquired on a Waters EMD 1000MS mass detector (ESI + mode, voltage 30 V) with an Xterra MS C18 5 μm 2.1 × 100 mm column and gradient eluent mode using 0.1% HCOOH in deionized water and MeCN or MeOH.