Solubilization and electrochemical stabilization of substituted phenols through the use of 2-hydroxypropyl-β-cyclodextrin

The effect of 2-hydroxypropyl-β-cyclodextrin (HPβCD) on the aqueous solubility and electrochemical stability of 2-substituted, 2,6-disubstituted and 2,4,6-trisubstituted phenols was investigated. All substituted phenols demonstrated an increase in water solubility ranging from 1.8 to 200-fold (in 40% HPβCD solutions). Cyclic voltammetry of a selected phenol, 2,6-diisopropylphenol, indicated addition of HPβCD increased the peak anodic potential and reduced the peak current consistent with cyclodextrin complex formation. Semiempirical molecular orbital methods (AM1) were used to examine complex structure and energetics.