Hydrothermal syntheses and crystal structures of two rectangular grid coordination polymers based on unique prismatic [M₈(ip)₈(4,4′-bipy)₈] building blocks [M = Ni(II) or Cd(II), ip = isophthalate, bipy = bipyridine]

Two new coordination polymers formulated as [Ni(ip)(4,4′-bipy)] (1) and [Cd(ip)(4,4′-bipy)]H₂O (2) have been hydrothermally prepared and structurally characterized. They crystallize in the triclinic space group P1̄ with Z=2 for 1 and monoclinic space group P2/c with Z=4 for 2, respectively. The dinuclear [M₂L₄(carboxylate)₄] units in each complex are bridged by V-shaped ip and linear 4,4′-bipy spacers to form unique prismatic [M₈(ip)₈(4,4′-bipy)₈] building blocks, which are further inter-connected through the mixed organic ligands to generate two-dimensional rectangular grids. The packing modes of the two two-dimensional grids are slightly different in the orientations of the ip aromatic rings with respect to the planes of the rectangular grid coordination polymers.