A 3-D Supramolecular Framework with Open Channels Constructed from Lanthanide Ions and Mixed Ligands

摘要

A 3-D supramolecular framework, [Er(pybz)2(Hnds)(H2O)2]·H2O (1, Hpybz = 4- pyridin-4-yl-benzoic acid, H2nds = naphthalene-1,5-disulfonic acid), based on lanthanide ions and mixed ligands has been hydrothermally synthesized. The structure was determined by single- crystal X-ray diffraction and further characterized by IR, elemental analysis and thermogravimetric analysis. Compound 1 crystallizes in the monoclinic system, space group P21/n with a = 9.849(2), b = 22.526(5), c = 17.167(4) , β =105.461(4)° and V = 3670.9(2) 3. In 1, two seven-coordinated Er3+ ions are bridged by two pybz- ligands to form a dimeric [Er2(COO)2] unit, which is further orderly linked by carboxyl of pybz- ligand to obtain a 1-D chain running along the a axis. Interestingly, significant H-bonding and π-π stacking interactions link the neighboring parallel chains leading to a 3-D supramolecular network structure which displays 1-D rhombus open channels (17.2 × 22.5).