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

First examples of lanthanide coordination polymers with 4,4'-biphenyldicarboxylic acid (4,4'-H(2)bpdc), Ln(4,4'-Hbpdc)(4,4'-bpdc)(H2O)(2) (Ln = Pr(1), Eu(2), Gd(3)) and Er(4,4'-bpdc)(1.5)(H2O)(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 Eu3+ ion site, which is consistent with the results of the X-ray crystal structure analysis. (C) 2004 Elsevier B.V. All rights reserved.