Self assembled macrobicycle and tricycle cages containing pyrrole rings by dynamic covalent chemistry method

Abstract

Synthesis of discrete macrobicycle and oligocycle molecules with three dimensional cavities in high yields remains very important because of their potential applications in the area of molecular recognition. Dynamic covalent chemistry method has effectively been used to synthesize such molecules. The Schiff base condensation reaction between tris(α-formylpyrrolyl-α′-methyl)amine and ethylenediamine readily afforded the large size [2 + 3] macrobicycle in very high yield. The analogous reaction between this trialdehyde and tris(2-aminoethyl)amine gave the [2 + 2] macrotricycle Schiff base in good yield. Subsequent reduction reactions using sodium borohydride yielded the corresponding saturated products in good yields. The anion binding ability of the [2 + 3] saturated macrobicycle was explained through the X-ray structure of the chloride anion encapsulated complex.