Correlation between ¹H NMR chemical shifts of hydroxyl protons in n-hexanol/cyclohexane and molecular association properties investigated using density functional theory

Association of n-hexanol molecules in cyclohexane forming clusters is studied by DFT and ¹H NMR. Geometry optimization, corrected binding energies, charge distributions, charge transfer energies, and ¹H NMR chemical shifts have been obtained. The calculated chemical shifts of hydroxyl protons have been correlated to experimental data obtained in the range of n-hexanol molar fraction between 0.002 and 0.2, showing that n-hexanol molecules at a molar fraction around 0.1, where well-structured hydrogen bond networks are observed, tend to form linear pentamers and hexamers. The experimental data are consistent with the continuous linear association thermodynamic model, showing a dimensionless association constant of 284.