Syntheses and characterization of aryl-substituted pyrogallol[4]arenes and resorcin[4]arenes

Seven aryl-substituted pyrogallol[4]arenes and six aryl-substituted resorcin[4]arenes were synthesized through the acid catalyzed reaction of either pyrogallol or resorcinol with a specific alkoxybenzaldehyde. Single crystal X-ray data was obtained for all thirteen compounds. In order to determine the effect of the different pendent -R groups, four properties were investigated: p-p distance, inward tilt, twist angle, and the angle between the planes containing the pendent -R groups. Positioning of the -R groups, the carbon atom chain length of the -R groups, the number of upper-rim hydroxyl groups (resorcin[4]arene vs. pyrogallol[4]arene), and the number of substituted phenyl groups all influenced these four properties. The trends that develop are investigated and discussed.