Chiral Moieties-Oriented Single-Stranded Helical Assembly of Calix[4]azacrown Derivatives

Bridging of calix[4]arene derivatives with optically active subunits derived from chiral l / d -amino alcohols has resulted in two novel calix[4]azacrowns enantiomers S -C 51 H 64 NO 7 ·CH 3 OH·H 2 O ( S -1 ) and R -C 51 H 64 NO 7 ·CH 3 OH·H 2 O ( R -1 ), which were crystallized separately. Single crystal X-ray diffraction studies revealed that they each encapsulate a methanol molecule by weak interactions and that they form supramolecular enantiomeric helical arrangements along the crystallographic axis, which are constructed via C–H···O hydrogen bonds involving bridging water molecules. A similar helical arrangement was also found in the crystal structure of a previously reported calix[4]azacrown compound S -C 108 H 146 N 2 O 16 ( S - 2 ).