Construction of a series of coordination polymers based on 1,4-naphthalenedicarboxylic and flexible dipyridyl ligands

Six new coordination polymers, {[Ag(bpa)]center dot(1,4-Hndc)}(n) (1), {[Ag(bpp)]center dot(1,4-Hndc)}(n) (2), [Cd(1,4-ndc)(bpa)(0.5)](n) (3), [Cd-2(1,4-ndc)(2)(bpp)](n) (4), [Zn(1,4-ndc)(bpa)(0.5)](n) (5) and [Co-2(H2O)(1,4-ndc)(2)(bpp)](n) (6), have been prepared under hydrothermal conditions (bpa = 1,2-bis(4-pyridyl) ethane, bpp = 1,3-bis(4-pyridyl) propane, 1,4-H(2)ndc = 1,4-naphthalenedicarboxylic). All these compounds were characterized by elemental analysis, IR spectroscopy, powder X-ray diffraction and single crystal X-ray diffraction. 1 and 2 are 1D coordination polymers. They are further linked by hydrogen-bonding interactions or Ag center dot center dot center dot Ag and hydrogen-bonding interactions to form a 2D (4,4) or (6,3) supramolecular network, respectively. 3 and 4 are 3D (4,5)-connected frameworks with the same structural motif. 5 comprises a 3D pcu net, and the pcu net is interpenetrated by a crystallographic equivalent net to form a two-fold interpenetrating 3D architecture. 6 exhibits a 3D 12-connected net. Thermal stability and photoluminescent properties of 1-6 were also investigated.