1D and 3D coordination polymers with the M(mu(1),mu(1)-X)(2)M motif (M = Na, Zn, Cd): Observation of a linear [Na(H2O)(4)](n)(n+) cation and a five-connected sqp-net

Artikel i vetenskaplig tidskrift, 2007

Three polymeric complexes [Zn(pydz)(N-3)(SO4)](n)[Na(H2O)(4)](n)(H2O)(4n) (1), [Cd(3-ampy)(N-3)Cl](n) (2), and [Cd(DENA)Cl-2(H2O)](n)(3), (pydz = pyridazine or 1,2-diazine, 3-ampy = 3-aminopyridine, DENA = NN-diethylnicotineamide) have been synthesized and characterized by spectral and structural methods and their network topologies analysed. Complex 1 crystallizes in monoclinic C-centred space group C2/m, the Zn(1) center is octahedrally coordinated; and simultaneously bridged by EO-azido, NN'-pydz, and O,O'-sulphato ligands. The ZnN4O2-octahedra form a ID anionic chain along b-axis. The Na(OH2)(6)-octahedra have also common water molecules, thus also forming a 1D chain along b-axis. The cationic and anionic chains are connected via hydrogen bonds of type O-H...O including lattice water molecules to form a supramolecular 3D network structure. In complex 2, the Cd(1) is six-coordinated by two EE-bridging azide groups, and two nitrogen atoms of bridging NN', 3-ampy ligand, and two bridging chloro ligands. The three different bridging ligands connect the distorted octahedra of the Cd(II) centres to form a 3D network structure with the topology of a square pyramidal net (4(3) (.) 6(6)-sqp). The centrosymmetric Cd2Cl2-rings are planar and the NH2- of the 3-ampy groups forms additional hydrogen bonds of type N-H...N to the adjacent azido groups. In complex 3, the octahedrally coordinated Cd(1) centres are occupied by alternating monodentate DENA ligand and a water molecule and the other four sites are occupied by four bridging chloro ligands. Thus the Cd2Cl2-rings form common edges to form 1D chains of Cd(II) octahedra along the b-axis of the monoclinic unit cell. 2D supramolecular sheets extended along the bc-planes of the unit cell are formed by the 0-H...O hydrogen bond. The IR spectra of the three complexes were measured and they confirm the X-ray structural data. (C) 2007 Elsevier Ltd. All rights reserved.