Synthesis, Molecular Recognition Of Novel Imidazolium Cyclophanes And Self-Assembly Of Imidazolium Compounds

The mimicking of biological functional systems is one of the active areas of modern chemistry, and two important factors of enzyme mimic are molecular recognition and self-assembly. The excellent behavior and application potential of imidazolium cyclophanes in enzyme mimic urged the article to concentrate on the design and synthesis of novel imidazolium cyclophanes as well as the study of their recognition abilities. In addition, the basic exploration about the self-assembly of imidazole compounds without metal cations has also been processed. A series of novel imidazolium cyclophanes with phenols have been designed and synthesized. And, an effective methodology to novel large cyclophanes with four imidazolium cations has been developed through introducing protective groups to argument spacial resistance. A type of interesting large imidazolium cyclophanes with alkyl spacer has highly symmetrical structures. UV spectraphotometric titration has been employed to investigate the molecular recognition ability of small imidazolium cyclophanes in acetonitrile. The binding constants Ks (dm3·mol-1) and Gibbs free energy changes -?G0 (kJ mol-1) were calculated according to the modified Benesi-Hildebrand equation. The experimental results indicate that cyclophane hosts can recognize simple molecular as well as guests with two-functional groups. The molecular recognition was mainly due to the second-order interaction such as π-π,cation-πinteractions and hydrogen bond of phenols. A regular assembly structure built by π-πstacking and hydrogen bond between imidazolium compounds and Br-has been analyzed under the help of X-ray, which provided references for the further investigation of self-assembly of imidazole compounds without metal cations.