Solvothermal synthesis and structures of lanthanide-organic sandwich coordination polymers with 4,4′-biphenyldicarboxylic acid

Abstract

First examples of lanthanide coordination polymers with 4,4′-biphenyldicarboxylic acid (4,4′-H 2bpdc), Ln(4,4′-Hbpdc)(4,4′-bpdc)(H 2O) 2 (Ln=Pr(1), Eu( 2), Gd( 3)) and Er(4,4′-bpdc) 1.5(H 2O) 2 ( 4) were prepared by the solvothermal synthesis. Crystallographic data show that complexes 1– 3 are isostructural and each lanthanide(III) ion is coordinated to six 4,4′-Hbpdc ligands, and display 3D sandwich structure with lanthanide ion layers and organic ligand layers alternately linking up with each other. Complex 4 shows different coordination modes of 4,4′-bpdc ligands from 1– 3 and each Er(III) ion is attached to four 4,4′-bpdc ligands to construct 3D sandwich structure. The emission spectrum of 2 shows one Eu 3+ ion site, which is consistent with the results of the X-ray crystal structure analysis.