Secondary amide catenane 1a was converted to the corresponding tertiary amide catenane 1b by repetitive treatment with a methylating system of CH 3I and KOH in DMSO. The amide functions of 1b were reduced with borane in refluxing THF to give the corresponding tertiary amine catenane 1c. Their structures were characterized by NMR, IR, and FAB-MS spectroscopies. An X-ray crystallographic analysis of 1c showed that its solid-state structure was stabilized by a CH-π interaction between the p-xylylene and m-xylylene units, together with a π-π stacking interaction between the two m-xylylene units. A variable temperature 1H NMR study suggested that 1c had components of highly enhanced mobility in CDCl 3, even at lower temperature, although a much weaker interaction, such as the CH-π interaction, existed between their components in solution. Tertiary amine rotaxane 3c was obtained from the corresponding secondary amide rotaxane 3a by a procedure similar to that used for 1a. The 1H NMR spectra indicated that the mobility of the components of 3c is sufficiently high even at lower temperature.
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