Fig. 6: Formation and isomerization behaviour of (1–H)+.
From: Controlling forward and backward rotary molecular motion on demand
a Interconversion of 1 s and (1–H)s+. b UV-vis spectra of (1–H)+ (1.0·10–5 m) in MeCN at 20 °C before and after irradiation to PSS with a 395 nm LED. The spectrum of 1 s before addition of HBF4·OEt2 is shown for comparison. The inset shows a fatigue study where the absorbance at 408 nm was followed over ten subsequent 180° rotations. c 1H NMR spectra (1–H)+ (2.5·10–3 m) in MeCN-d3 at −30 °C before and after irradiation to PSS with a 395 nm LED as well as after completed THI. d Potential energy diagram of isomerization pathways of (1–H)+ under high polarity conditions. The energies of the lowest energy pyrrolidine conformer as obtained by DFT (SMD(MeCN)-CAM-B3LYP/6-31 G(d,p)) are reported in kJ·mol–1. The experimental value for the activation barrier of THI is shown for comparison.
