Avance 500 nmr spectrometer

All chemicals were purchased from Sigma-Aldrich, Acros Chemicals, Fluorochem or Alfa Aesar and used without further purification unless otherwise stated. Anhydrous acetonitrile was obtained from a MBraun SPS800 solvent purification system unless otherwise stated. Flash column chromatography was performed using Biotage Flash Purification system. ¹H NMR and ¹³C NMR spectra were measured on a Bruker Avance 500 NMR spectrometer and Bruker Avance DPX400 spectrometer. ¹H NMR and ¹³C NMR spectra are reported as chemical shifts in ppm downfield from TMS and J values are given in Hertz. ³¹P NMR spectra were recorded on Bruker Avance DPX400 spectrometer or Bruker Avance 500 NMR spectrometer and are reported in chemical shifts downfield from 85% H₃PO₄. Reverse phase HPLC was performed on a system comprising of a Dionex P680 pump and a Dionex UVD170U detector unit.

All the reagents involved in this research were commercially available and used without further purification unless otherwise noted. Solvents were either employed as purchased or dried before use by standard laboratory procedures. Thin-layer chromatography (TLC) was carried out on 0.25 mm Leyan silica gel plates (60F-254). Column chromatography was performed on silica gel (200-300 mesh) as the stationary phase. ¹H, ¹³C NMR, 2D NMR spectra were performed on Bruker Avance-500 NMR spectrometers. Chemical shifts are reported in ppm with residual solvents or tetramethylsilane (TMS) as the internal standards. The following abbreviations were used for signal multiplicities: s, singlet; d, doublet; dd, doublet of doublet; m, multiplet. Host-guest complexes were prepared by simply mixing the guests and hosts in 1: 1 stoichiometry in the corresponding solvent. Electrospray-ionization high-resolution mass spectrometry (ESI-HRMS) experiments were conducted on an applied Q-EXACTIVE mass spectrometry system. Circular Dichroism (CD) and UV-Vis spectra were recorded on an Applied Photo Physics Chirascan CD spectropolarimeter, using a 1 cm quartz cuvette. Fluorescent spectra were recorded on a spectrofluorometer (Edinburgh FS5), using a 1 cm quartz cuvette. Specific rotations were measured on Rudolph Research Analytical Autopol I Polarimeter (589 nm) in a 1 dm length cell under 25 °C.

Optical rotations were measured with a Rudolph Autopol I polarimeter (Rudolph, Hackettstown, NJ, USA). UV spectra were recorded on a Shimadzu UV-2550 spectrometer (Beckman, Kyoto, Japan). ECD spectra were measured on a JASCO J-715 spectrophotometer (JASCO, Tokyo, Japan). IR absorptions were obtained on a Nicolet 380 FT-IR instrument (Thermo, Pittsburgh, PA, USA) using KBr pellets. HRESIMS were determined by an API QSTAR Pulsar mass spectrometer (Bruker, Bremen, Germany) or 6200 series TOF/6500 series (Agilent, Palo Alto, CA, USA). The NMR spectra were recorded on Bruker Avance 500 NMR spectrometers (Bruker, Bremen, Germany), using TMS as an internal standard. HPLC purifications were performed on an analytical reversed-phase column (YMC-packed C₁₈, 250 mm × 10 mm, 5 µm) (YMC, Tokyo, Japan) using a G1311C 1260 Quat Pump VL and detected with a G1315D 1260 DAD VL detector (190–500 nm) (Agilent Technologies 1260 infinity, Palo Alto, CA, USA). Column chromatography was performed with silica gel (60–80, 200–300 mesh, Qingdao Haiyang Chemical Co., Ltd., Qingdao, China), ODS gel (20–45 µm, Fuji Silysia Chemical Co., Ltd., Durham, NC, USA), and Sephadex LH-20 (Merck, Darmstadt, Germany). TLC was carried out on NUSCRIPT silica gel GF254 (Qingdao Haiyang Chemical Co., Ltd., China), and peaks were detected by spraying with 5% H₂SO₄ in EtOH followed by heating.