IR spectroscopy on jet-cooled isolated two-station rotaxanes.

High-resolution IR spectroscopy has been employed to study isolated, switchable [2]rotaxanes. IR absorption spectra of two-station rotaxanes, their separate thread, and macrocycle components, as well as those of the individual stations incorporated into the thread, have been measured in the 1800-1000 cm(-1) region. These spectra have been fully analyzed, aided by quantum chemical predictions of the IR spectra. From these analyses, a comprehensive picture emerges of the conformational structure and binding interactions between the mechanically interlocked components of the rotaxane.