Synthesis of [n]Rotaxanes by Template-Directed Clipping: The Role of the Dialkylammonium Recognition Sites

Linear and rectangular [n]rotaxanes were synthesized by template-directed clipping of heterocrown ether components onto the dumbbell-shaped molecules containing different dialkylammonium recognition sites. The effect of the structure of the dialkylammonium sites on the clipping efficiency was investigated, and selective clipping led to formation of a rectangular [4]rotaxane.