Multinuclear NMR spectroscopy of ethanol isotopic forms in the liquid and gas phase

• Published in: Journal of molecular structure 2022-04, Vol.1254, p.132335, Article 132335
• Main Authors: Makulski, Włodzimierz, Godlewski, Mateusz
• Format: Article
• Language: English
• Subjects: Ethanol isotopomers; Gas-phase studies; Nuclear magnetic shielding; Spin-spin coupling constants
• ISSN: 0022-2860; 1872-8014
• DOI: 10.1016/j.molstruc.2022.132335

•1H, 13C and 17O NMR shielding in the isolated ethanol molecule were measured at 300 K.•All shielding gas-to-liquid shifts in ethanol are negative values.•1J(CH), 1J(CC) and 1J(OH) spin-spin coupling constants were measured in the gaseous ethanol molecule.•Second virial coefficients of intermolecular interactions Xe-C2H5OH and SF6C2H5OH were established. Several ethanol isotopic species were dissolved in the buffer gases, Xe and SF6, and carefully investigated by NMR spectroscopy. The 1H, 13C and 17O chemical shifts converted to magnetic shielding constants were obtained by extrapolation of the NMR parameters to the zero-density limit of the gaseous mixtures. These nuclear shielding constants are free from intermolecular interactions and can be directly compared with quantum calculation results. At the same time, the second virial coefficients of 1H, 13C and 17O chemical shielding were obtained from the slopes of density dependences. High resolution NMR spectra were also recorded for neat samples to allow measurements of appropriate gas-to-liquid shifts. They reflect the association processes which take place during condensation from gas to the liquid state. Several spin-spin coupling constants in the ethanol molecule were measured in the gas and liquid phase. The changes to the NMR parameters in different phases and isotopic compositions were given and briefly discussed. [Display omitted]