Dynamics of Hydrogen Bonding in Three‐Component Nanorotors

The dynamics of hydrogen bonding do not only play an important role in many biochemical processes but also in Nature's multicomponent machines. Here, a three‐component nanorotor is presented where both the self‐assembly and rotational dynamics are guided by hydrogen bonding. In the rate‐limiting step of the rotational exchange, two phenolic O‐H–N,N((phenanthroline)) hydrogen bonds are cleaved, a process that was followed by variable‐temperature (1)H NMR spectroscopy. Activation data (ΔG (≠) (298)=46.7 kJ mol(−1) at 298 K, ΔH (≠)=55.3 kJ mol(−1), and ΔS (≠)=28.8 J mol(−1) K(−1)) were determined, furnishing a rotational exchange frequency of k (298)=40.0 kHz. Fully reversible disassembly/assembly of the nanorotor was achieved by addition of 5.0 equivalents of trifluoroacetic acid (TFA)/1,8‐diazabicyclo[5.4.0]undec‐7‐ene (DBU) over three cycles.