CH···O Hydrogen Bonds in “Clicked” Diketopiperazine-Based Amide Rotaxanes
摘要:
Two amide [2]rotaxanes were synthesized in high yields using a novel N,N-clipropargyl diketopiperazine axle centerpiece as the template to which the stoppers are attached through "click chemistry". H-1 and 2D NMR spectra provide evidence for two different H-bonding motifs, in one of which the triazole CH groups form C-H center dot center dot center dot O=C bonds with the wheel carbonyl O atoms. This motif can be controlled and switched reversibly by competitive anion binding.