Manipulating the conformation and interplay of p-sulfonated calix[4]arenes by lower rim tri-substitution with N′-cyanocarbamimidate groups†
Abstract
p-Sulfonatocalix[4]arenes with three of the lower rim hydroxyl groups substituted with N′-cyanocarbamimidate groups crystallizes in the 1,3-alternate conformation rather than the common cone conformation for unsubstituted calixarenes, which also results in departure from the common bilayer arrangement of sulfonated calix[4]arenes. The new calixarene formed via reaction of the phenolic moieties of the p-sulfonatocalix[4]arene with the dicyanamide anion derived from an ionic liquid with an imidazolium cation.