Neo 400 mhz spectrometer

Ammonium metavanadate (NH₄VO₃, 99%) and D-mannitol (C₆H₁₄O₆, 98%), both from Sigma-Aldrich^® (St. Louis, MO, USA), and tetramethylammonium chloride (C₄H₁₂ClN, 98%) from Fluka^® were used without purification. Deuterium oxide (D₂O, 99.9 atom %D) was purchased from Oakwood Chemical and used as received. Ultrapure water (18.2 mΩ·cm) was used in the synthesis and characterization of V₁₅, excepted when otherwise stated. The ⁵¹V NMR data were collected on a Bruker NEO 400 MHz spectrometer with a 105.2 MHz frequency for vanadium at 298 K, using 4096 scans in the f1 domain, 8 steady-state transitions, a spectra width of 800 ppm, a transmitter frequency offset of −548 ppm, 0.01 s relaxation delay, a 0.08192 s acquisition time, and a 16 μs pulse. Fourier-transform infrared (IR) spectra (400 to 4000 cm^–1) were recorded from KBr pellets on a Bruker VERTEX-70 spectrometer with a resolution of 4 cm⁻¹. Electron paramagnetic resonance in X-band (EPR) spectra (9.5 GHz) were recorded at 77 K on an X-band (9.5 GHz) Bruker EMX-Micro spectrometer using a pulverized sample. Electronic absorption spectra of 0.250 mmol L⁻¹ aqueous solution of V₁₅ were observed from 340 to 900 nm, using an AvaLight UV-Vis/NIR light source and an AvaSpex-UL S2048 Fiber-Optic Spectrometer.