Structural diversity of four lanthanide metal–organic frameworks based on 2,6-naphthalenedicarboxylate: synthesis, structures and photoluminescent properties

Abstract
We report the crystal structures of four different neutral lanthanide (Ln = La, Nd, Eu and Gd) metal–organic frameworks based on the organic linker 2,6-naphthalenedicarboxylate (NDC). The materials are three-dimensional and crystallize in three distinct topologies, with distinct bonding modes of NDC and lanthanide coordination numbers ranging from seven to nine and varying geometry. We denote our materials SLUG-49 [La6(NDC)9(DMF)3·6 DMF], -50 [Nd2(NDC)3O(DMF)2], -51 [Eu2(NDC)3(DMF)2·DMF], and -52 [Gd4(NDC)6(DMF)4] (DMF = N,N-dimethylformamide). The structures exhibit similar thermal decomposition profiles and infrared spectra. The Eu(III)-based material exhibits a sharp red-orange luminescence at 613 nm with a quantum efficiency of 3.56%.
Funding Information
  • Division of Chemical, Bioengineering, Environmental, and Transport Systems (1603754)