title: A three-dimensional coordination polymer based on the Zn₄(μ₃-OH)₂ unit: poly[[(μ₄-benzene-1,4-dicarboxylato)bis(μ₃-benzene-1,4-dicarboxylato)bis(μ₃-hydroxido)bis(1,10-phenanthroline-5,6-dione)tetrazinc] dihydrate].
abstract: The title compound, {[Zn4(C8H4O4)3(OH)2(C12H6N2O2)2]·2H2O}n, has been prepared hydrothermally by the reaction of Zn(NO3)2·6H2O with benzene-1,4-dicarboxylic acid (H2bdc) and 1,10-phenanthroline-5,6-dione (pdon) in H2O. In the crystal structure, a tetranuclear Zn4(OH)2 fragment is located on a crystallographic inversion centre which relates two subunits, each containing a [ZnN2O4] octahedron and a [ZnO4] tetrahedron bridged by a μ3-OH group. The pdon ligand chelates to zinc through its two N atoms to form part of the [ZnN2O4] octahedron. The two crystallographically independent bdc(2-) ligands are fully deprotonated and adopt μ3-κO:κO':κO'' and μ4-κO:κO':κO'':κO''' coordination modes, bridging three or four Zn(II) cations, respectively, from two Zn4(OH)2 units. The Zn4(OH)2 fragment connects six neighbouring tetranuclear units through four μ3-bdc(2-) and two μ4-bdc(2-) ligands, forming a three-dimensional framework with uninodal 6-connected α-Po topology, in which the tetranuclear Zn4(OH)2 units are considered as 6-connected nodes and the bdc(2-) ligands act as linkers. The uncoordinated water molecules are located on opposite sides of the Zn4(OH)2 unit and are connected to it through hydrogen-bonding interactions involving hydroxide and carboxylate groups. The structure is further stabilized by extensive π-π interactions between the pdon and μ4-bdc(2-) ligands.
authors: College of Chemistry, Fuzhou University, Fuzhou, Fujian 350116, People's Republic of China.
authors: Meng
authors: M
authors: Wen
authors: College of Chemistry, Fuzhou University, Fuzhou, Fujian 350116, People's Republic of China.
authors: Zu-Ping
authors: ZP
authors: Xiao
authors: College of Chemistry, Fuzhou University, Fuzhou, Fujian 350116, People's Republic of China.
authors: Chun-Ya
authors: CY
authors: Wang
authors: College of Chemistry, Fuzhou University, Fuzhou, Fujian 350116, People's Republic of China.
authors: Xi-He
authors: XH
authors: Huang
keywords: 1,10-phenanthroline-5,6-dione; benzene-1,4-dicarboxylic acid; crystal structure; pcu net; polynuclear metal clusters; tetranuclear zinc polymer; three-dimensional coordination polymer; α-Po topology