Lanthanide‐Functionalized Water‐Soluble Ionic Motors: Synergetically Regulated Rotary Motion by Allostery and Triplet Sensitization.

Molecular motors, based on overcrowded alkenes (L) serving as ligands to chelate lanthanide nitrate, afford the first lanthanide‐functionalized water‐soluble ionic compound [L2‐Ln(NO3)2(H2O)2]·NO3 (LnL2). Benefitting from the "pull–push" feature of L together with 3LMCT from L to LnIII, irradiation with visible light not only drives photochemical isomerization but also induces energy transfer from L to LnIII, decreasing their intensity of low‐energy 3LMCT (ligand‐to‐metal triplet energy transfer) absorptions and sensitizing the Ln‐based luminescence. Thus, the typical EuIII‐based luminescence of EuL2 favors tracing its movement by time‐resolved luminescence, and temperature‐dependent luminescence renders it possibly to be used as potential luminescent thermometers. Very excitingly, besides a contraction of the stator by Ln–L interactions on decreasing the steric hindrance on the "fjord region," the efficiency of intramolecular 3LMCT sensitization synergetically regulates the rotary motion of lanthanide‐complexed motors in thermal helix inversion steps. [ABSTRACT FROM AUTHOR]