Hydrogen bonding between phenols and fatty acid esters: (1)H NMR study and ab initio calculations

structure: see text] (1)H NMR measurements and ab initio calculations were used to study the interactions between hindered/nonhindered phenols and carboxylic acid esters. The dihedral angle (phi) between the OH group and a plane of the aromatic ring is close to 0 degrees in the hydrogen-bonded nonhindered phenols, whereas for 2,6-di-tert-butyl-4-methylphenol the OH group is completely twisted out of the aromatic plane (phi approximately 90 degrees ).