Self-Assembly of Triple-Stranded Lanthanide Molecular Quasi-Lantern Containing 2,2 & PRIME;-Bipyridine Receptor: Luminescence Sensing and Magnetic Property

Ln(2) L (3)-type supramoleculararchitectureshave received significant attention recently due to their unique magnetismand optical properties. Herein, we report the triple-stranded Ln(2) L (3)-type lanthanide molecular quasi-lanterns,which are fabricated by the deprotonation self-assembly of a linearligand featuring a & beta;-diketone chelating claw and 2,2 & PRIME;-bipyridine(bpy) moiety with lanthanide ions (Ln = Eu3+ and Dy3+). The crystal structure analysis indicates that Eu3+ and Dy3+ ions are all coordinated by eight oxygen donorsbut in different coordination geometries. The eight oxygen donorsin Eu-2 L (3) and Dy-2 L (3) are arranged in a square antiprism and triangulardodecahedron geometry, respectively. Taking into account the factthat the bpy moiety has a strong coordination affinity for transitionmetal ions, luminescence sensing toward Cu2+ ions has beendemonstrated with Eu-2 L (3), bearinga detection of limit as low as 2.84 ppb. The luminescence sensingbehavior of Eu-2 L (3) is ascribed tothe formation host-guest complex between Eu-2 L (3) and Cu2+ ions with a 1:2 bindingratio. Dynamic AC susceptibility measurements for Dy-2 L (3) reveal the relaxation of magnetization in it.This work provides a potential way for design and fabrication of lanthanide-basedmolecular materials with functions endowed by the ligands.