Self-assembly and luminescence of trinuclear lanthanide based supramolecular circular helicates

Abstract

A series of trinuclear lanthanide circular helicates [Ln₃L₃]Cl₃ have been synthesized via supramolecular subcomponent self-assembly. Photophysical studies demonstrate that the unique helical bis-tetradentate 1,29-dialdehyde ligand L²⁻ could serve as an effective sensitizer for Sm^III, Eu^III, Nd^III and Yb^III ions exhibiting efficient characteristic fluorescence emission because of the shell-type blocking of the ligand, which makes them the first circular helicates exhibiting near-infrared lanthanide fluorescence.