Study of [2]- and [3]Rotaxanes Obtained by Post-Synthetic Aminolysis of a Kinetically Stable Carbonate-Containing Pseudorotaxane

Abstract

Here is reported the synthesis and study of dibenzo-24-crown-8 (DB24C8)-based [2]- and [3]rotaxanes that contain an ammonium as the best molecular station and carbamate moieties as secondary molecular stations. The common post-interlocking synthesis relies on the aminolysis of the N-succinimidyl carbonate extremity of an activated though insulated pseudorotaxane. The N-succinimidyl carbonate-based thread's extremity proved to be small enough to allow the slow slippage of the DB24C8 around the thread and large enough to allow insulation of the kinetically stable pseudorotaxane. Due to its sensitivity towards amine compounds, the activated carbonate end of the encircled thread allowed post-interlocking aminolysis-based conversion into mechanically interlocked rotaxanes by providing the same way the carbamate secondary station for the DB24C8 in the thread backbone. Translation of the DB24C8 along the threaded axle between the two molecular stations was investigated.