Triphenylphosphonium stoppered [2]rotaxanes

[GRAPHICS] The template directed syntheses of two [2]rotaxanes, one carrying one and t he other two triphenylphosphonium stoppers, have been achieved using a thre ading-followed-by-stoppering approach. Either one or two benzylic bromide f unctions-located at the para positions of dibenzylammonium-based ions, whic h become encircled by dibenzo[24]crown-8 macrocycles during the initial the rmodynamically controlled phases that mark the recognition events-serve as sites for nucleophilic attack by triphenylphosphine during the subsequent k inetic stages that lead to the formation of the two [2]rotaxanes.