Fig. 3: Light- and redox-induced switching of BTX.

a Schematic depiction of all three switching states of BTX. b Change of absorbance of BTX-gel upon irradiation with 365 nm light in water at 25 °C. c Change of absorbance of BTX-gel upon oxidation to BTX-gel²⁺ by chemical oxidation with 15 mm CAN in water. d–f CVs of BTX-MA and BTX-gel (on ITO) in CH₂Cl₂, 100 mm TBAPF₆. The black arrows indicate the starting point and direction of the first scan. For solution-phase studies, a glassy carbon (GC) working electrode was used (see also Supplementary Fig. 13 for CVs measured using Pt). d 0.5 mm BTX-MA at ν = 100 mV s⁻¹. The absence of a reduction peak in the first (light blue) scan illustrates the hysteretic, dynamic nature of the redox switching; unless the dicationic switching state is first (electrochemically) generated, no reduction is observed. The peak marked with an asterisk arises from the oxidation of the syn-folded state. e 0.25 mm BTX-MA at ν = 25 mV s⁻¹. f BTX-gel on ITO at ν = 100 mV s⁻¹. The syn-folded state, obtained by continuous, in situ irradiation of the solution with 365 nm light, displays a significantly more cathodic oxidation potential (e and f).