Monoester copillar[5]arenes: synthesis, unusual self-inclusion behavior, and molecular recognition.

The self-inclusion behavior of monoester copillar[5]arenes depends on the position of the ester group, which causes different guest selectivities. Monoester copillar[5]arenes bearing an acetate chain can form stable self-inclusion complexes in low- and high-concentration solution and exhibit high guest selectivity. However, a monoester copillar[5]arene bearing a butyrate chain can not form a self-inclusion complex and exhibits low guest selectivity. Thus, a new class of stable self-inclusion complexes of copillar[5]arenes was explored to improve the selectivity of molecular recognition.