Chiral [1]rotaxanes with a two-fold bridge based on phenylacetylene macrocycles (PAMs): two different chiroptical properties created by 7PAM

Abstract

We describe the unique chiroptical properties of chiral [1]rotaxanes 1 and 2 based on the assembly of an achiral ring of phenylacetylene macrocycle (7PAM) and an achiral p-phenylene ethynylene rod with a two-fold bridge. In both cases, mechanical helical chirality is generated by the relative occupation of the ring and rod. Through the intramolecular transmission of the mechanical helical chirality to the bridge, we demonstrate that two different chiral conformations were present in a particular form of enantiomers in 2.