Solvothermal synthesis and structural characterization of a novel erbium(III)-carboxylate polymeric complex

A novel erbium(III)-carboxylate polymeric complex [{Er(H2btec)2/4(btec)3/6(H2O)}·2H2O]n, simplified as ECPC, (H4btec=1,2,4,5-benzenetetracarboxylic acid) was synthesized under solvothermal conditions (H2O/acetic acid). ECPC obtained was characterized by differential thermal analysis/thermogravimetry (DTA/TG), single-crystal X-ray diffraction, elemental analysis and FT-IR analysis techniques. The result of single-crystal X-ray diffraction analysis shows that the ECPC crystallizes in monoclinic symmetry, and the space group P2(1)/n, a=10.6933(15) Å, b=7.1243(10) Å, c=17.092(2) Å, α=γ=90°, β=97.109(2)°, V=1292.1(3) Å3, Z=4, R1=0.0286, wR2=0.0686. ECPC demonstrates a 3-D supramolecular framework containing nine-coordinate erbium centers and channels. The uncoordinated water molecules occupy the channels in ECPC. The results of TG/DTA, IR and elemental analysis performed also give positive information of the proposed crystal structure.