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

摘要

Molecular motors, based on overcrowded alkenes (L) serving as ligands tochelate lanthanide nitrate, afford the first lanthanide-functionalizedwater-soluble ionic compound [L_2-Ln(NO_3)_2(H_2O)_2]·NO_3 (LnL_2). Benefittingfrom the “pull–push” feature of L together with ~3LMCT from L to Ln~Ⅲ,irradiation with visible light not only drives photochemical isomerization butalso induces energy transfer from L to Ln~Ⅲ, decreasing their intensity oflow-energy ~3LMCT (ligand-to-metal triplet energy transfer) absorptions andsensitizing the Ln-based luminescence. Thus, the typical Eu~Ⅲ-basedluminescence of EuL_2 favors tracing its movement by time-resolvedluminescence, and temperature-dependent luminescence renders it possiblyto be used as potential luminescent thermometers. Very excitingly, besides acontraction of the stator by Ln–L interactions on decreasing the sterichindrance on the “fjord region,” the efficiency of intramolecular ~3LMCTsensitization synergetically regulates the rotary motion oflanthanide-complexed motors in thermal helix inversion steps.