In addition to the 1 H- N HMQC spectrum for rotaxane 1 (Fig. ), spectra for the axle 2 and macrocycle 3 components were obtained to account for through bond correlations of non-hydrogen bonded spin systems (see ESI Fig. ). To maximize F1 resolution, the N chemical shift window was restricted between 40-160 ppm, nJ NH long-range correlations that were deshielded outside this window are aliased in F1 as a consequence of the echo-antiecho selection used in the gradient HMQC sequence. Such spectral folding is observed in all spectra (See ESI for further details and Fig. as an example). A downfield shift for the triazole proton H A from 8.24 ppm to 10.30 ppm was observed for the rotaxane relative to the component axle 2 indicative of hydrogen-bonding (see ESI, Fig. ). All five nitrogen environments for rotaxane 1 were observed (Fig. ) and could be assigned using 1 and 2D NMR (Table ). Correlation between proton H A on the triazole, and bipyridine nitrogen atoms N a and N b is observed indicating through-space interaction. This through-space correlation signifies direct orbital communication between the hydrogen and nitrogen atoms, i.e. a proximity enforced hydrogen bond. The two pyridyl rings in the bipyridine are inequivalent and move upfield relative to macrocycle 3. Prior solid-state studies on mechanically interlocked architectures incorporating macrocycle 3 imply preferential hydrogen-bonding of H A to N a , however a preference cannot be established on the basis of this NMR experiment. ppm corresponding to the bipyridinium proton H l (Fig. ). In the 1 H-15 N HMQC spectra for 1[HPF6] all five nitrogen environments are observed (Table , see also Fig. ). Bipyridine nitrogen atoms N a and N b move downfield relative to the unprotonated macrocycle, in particular N a , indicating protonation. The cross peak for H l resolves as a doublet (see also Fig. ), with a 1J coupling constant of 86.7 Hz, typical of 1J values observed in enriched systems. The experiment thus unambiguously establishes the site of protonation which is in agreement with that proposed for a previously reported solid-state structure for a related rotaxane. No correlation was observed between H l and the nitrogen atoms of the triazole.