Supporting Information

Files in this Data Supplement:

Supporting Table 3
Supporting Figure 5
Supporting Figure 6
Supporting Figure 7
Supporting Text
Supporting Figure 8
Supporting Figure 9
Supporting Figure 10
Supporting Figure 11
Supporting Figure 12
Supporting Scheme 3
Supporting Scheme 4
Supporting Scheme 5




Supporting Figure 5

Fig. 5. Transient absorption difference spectra (degassed acetonitrile solution, room temperature) of rotaxane 1⁶⁺ 0.6 (a), 1.2 (b), 1.7 (c), 2.5 (d), and 4.0 (e) ms after 532-nm nanosecond laser excitation. (Inset) Transient absorption spectrum observed 6 m s after light excitation.

Supporting Figure 6

Fig. 6. Transient absorption difference spectra (degassed acetonitrile solution, room temperature) of reference compound 3²⁺ 0.6 (a), 1.2 (b), 1.7(c), and 2.7 (d) ms after 532-nm nanosecond laser excitation. (Inset) Transient absorption kinetics monitored at 450 nm (dashed line) and at 398 nm (full line).

Supporting Figure 7

Fig. 7. Transient absorption kinetics, monitored at l_iso = 398 nm, of rotaxane 1⁶⁺, dumbbell-shaped component 2⁶⁺, and model compound 3²⁺ after 532-nm nanosecond laser excitation (degassed acetonitrile solution, room temperature).

Supporting Figure 8

Fig. 8. Detail of the transient UV-Vis absorption difference spectra of deaerated acetonitrile solutions containing 1.0 ´ 10^–4 mol·liter^–1 1⁶⁺ (a) or 2⁶⁺ (b) and 5.0 ´ 10^–5 mol·liter^–1 ptz, recorded at delays of 7, 40, 80, 130, 200, 300, 400, 550 and 850 ms after 532-nm laser excitation at 303 K.

Supporting Figure 9

Fig. 9. Comparison of the normalised transient difference absorption spectra in the 378-403 nm spectral region obtained 7 ms (full line) and 900 ms (dashed line) after the laser pulse for rotaxane 1⁶⁺ (a) and the ringless compound 2⁶⁺ (b) in the presence of ptz (degassed acetonitrile, 303 K).

Supporting Figure 10

Fig. 10. Comparison of the normalised transient difference absorption spectra in the 378-403 nm spectral region for rotaxane 1⁶⁺ (full line) and the ringless compound 2⁶⁺ (dashed line) in the presence of ptz, obtained 7 ms (a) and 900 ms (b) after the laser pulse (degassed acetonitrile, 303 K).

Supporting Figure 11

Fig. 11. Eyring plot showing the temperature dependence of k_rd in the range 284–303 K.

Supporting Figure 12

Fig. 12. Simulation of the transient absorption experiments in the presence of ptz, carried out by using the determined kinetic parameters. (a) Simulated time profiles of the concentration of conformations B' and C' (Scheme 3) at 284 K. (b) Simulated transient absorption spectra, obtained by Eq. S4 with the concentration profiles shown in a, at various times from 0 to 2 ms. Gaussian-shaped bands were assigned to each conformation (fwhm = 25 nm; |l_max,0 – l_max,¥| = 3 nm). (c) Simulated values of l_max of the bands shown in b as a function of time (full line). The experimental values of l_max are plotted as circles. For more details on these calculations, see the text.

Supporting Scheme 3

Scheme 3. The processes which take place after generation of conformation B' of 1⁵⁺ by light excitation of 1⁶⁺ in the presence of phenothiazine. The phenothiazine radical cation, ptz⁺, is produced in concomitance with 1⁵⁺ (processes 2 and 8 in Scheme 2b).

Supporting Scheme 4

Scheme 4. The processes which take place after generation of conformation B by light excitation of 1⁶⁺.

Supporting Scheme 5

Scheme 5. Free energy changes for the processes associated with the reversible one-electron reduction of rotaxane 1⁶⁺. (a) Square scheme representing the processes. For simplicity, we have represented only the part of 1⁶⁺ containing the bipyridinium stations. (b) Graphical representation of how the energy profile of shuttling changes upon reduction of >A₁²⁺. The thermodynamic parameters in the square scheme are as indicated in the text and labels I–IV correspond to the structures in part A.