A Novel Strategy To Assemble Achiral Ligands to Chiral Helical Polyrotaxane Structures

Using the achiral N,N′-bis(2-pyridylmethyl)-1,6-hexanediamine ligand bearing two end pyridyl groups as the source of conformational chirality, a novel type of TMeQ[6]-based helical polyrotaxane was prepared and characterized by X-ray crystallography and 1H NMR spectroscopy. The chirality of the polyrotaxane was generated from twisting of the hexylidene of the N,N′-bis(2-pyridylmethyl)-1,6-hexanediamine “string” when bound within the hydrophobic cavity of TMeQ[6]. Two opposite chiral helical polyrotaxanes crystallize as a racemic compound.