Xiu-Qing Zhang

Synthesis, structures, and characterization of cadmium(II), cobalt(II), and copper(II) metal polymers with tetrazole-1-acetate

Three new coordination polymers {[Cd(tza)(2,2′-bpy)(H2O)](ClO4)} n 1, {[Co(tza)(2,2′-bpy)(H2O)](ClO4)} n 2, and {[Cu(tza)(phen)](ClO4)} n 3 (Htza = tetrazole-1-acetic acid, 2,2′-bpy = 2,2′-bipyridyl, phen = 1,10-phenanthroline) were synthesized and characterized by X-ray single-crystal diffraction, elemental analysis, and IR spectra. Complexes 1 and 2 exhibit 3-D architectures formed by π–π interaction of 2,2′-bpy ligands interlinking to the adjacent 2-D layers. Complex 3 is a 1-D zigzag double chain and the 3-D structure is formed by π–π stacking interaction of phen and nonclassical hydrogen bonding.

{N,N-Dimethyl-N′-[phen­yl(2-pyrid­yl)methyl­ene]ethane-1,2-diamine-κ3N,N′,N′′}dithio­cyanato-κN,κS-copper(II)

In the title complex, [Cu(NCS)2(C16H19N3)], the CuII atom is coordinated by a total of four N atoms; three from one tridentate Schiff base ligand and one from one of the NCS− ions. The S atom from the other NCS− ion completes the distorted square-pyramidal coordination.

Synthesis, crystal structures, and fluorescence properties of transition metal complexes derived from an unsymmetrical N-heterocyclic ligand

Four transition metal complexes, [Mn(Hbimtz)2(H2O)2(NCS)2] (1), [Co(Hbimtz)2(H2O)2(NCS)2] (2), [Pb(Hbimtz)Br2] n (3), and {[Ag2(Hbimtz)3]SO4 · 4H2O} n (4) (Hbimtz = 1-[(1H-benzimidazol-2-yl)-methyl]-1,2,3,4-tetrazole), were synthesized and characterized by single-crystal X-ray diffraction. The Mn(II) of 1 and Co(II) of 2 are six-coordinate with two nitrogen atoms from Hbimtz, two nitrogen atoms from thiocyanate and two water molecules. The geometry of Pb(II) in 3 is a distorted octahedron with two nitrogen atoms of two Hbimtzs and four Br− ions, including the weak bond between the Pb1 and N6 of Hbimtz. Complex 3 is assembled into a 1-D [PbBr2] n inorganic chain by μ 2-Br− and into a 2-D layer by weak interactions. The Ag(II) of 4 has two geometries, linear and tetrahedral. Hbimtz bridges the two kinds of Ag(II) into a 1-D helical chain. Fluorescence of 3 and 4 were also investigated.

Aqua[N-(2,5-dihydroxybenzyl)imino­diacetato]copper(II)

The title complex, [Cu(C11H11NO6)(H2O)], contains a CuII atom in a distorted square-pyramidal geometry. The metal centre is coordinated in the basal sites by one water molecule and two carboxylate O atoms and one N atom of the tetradentate ligand [Cu—O range, 1.9376 (11)–1.9541 (12), Cu—N, 1.9929 (12) Å] while the apical site is occupied by a hydroquinone O donor atom [Cu—O, 2.3746 (12) Å]. Intermolecular hydrogen bonding interactions involving both hydroquinone hydroxy groups and the coordinated water as donors give a three-dimensional framework structure.

Synthesis, crystal structures and thermogravimetric analyses of Mn(II) and Cu(II) complexes derived from 1,4,5,6-tetrahydro-6-oxo-3-pyridazinecarboxylic acid

Two Cu(II) complexes: [Cu(topca)2]·2H2O, [Cu(topca)2]·4H2O, and two Mn(II) complexes: {[Mn(topca)(H2O)3](topca)·2H2O}n and {[Mn(topca)(H2O)3](ClO4)}n (where Htocpa = 1,4,5,6-tetrahydro-6-oxo-3-pyridazinecarboxylic acid), have been synthesised and their structures determined. The Cu(II) centres are four-coordinated with two pyridazinyl N atoms and two carboxyl O atoms from two ligands, while the geometry of the Mn(II) atoms is distorted octahedral with O, N atoms of two ligands and O atoms of three water molecules. The two Mn complexes are assembled in a 1-D chain structure by bridging carboxyl-O atoms.

Synthesis and crystal structures of four transition metal complexes with 1,4,5,6-tetrahydro-6-oxo-3-pyridazinecarboxylic acid

Four transition metal complexes [Zn(topca)2(H2O)2], [Zn(topca)2(H2O)2]·2H2O, [Ni(topca)2(H2O)2]·2H2O and [Cd(topca)2 (H2O)2], (Htocpa = 1,4,5,6-tetrahydro-6-oxo-3- pyridazinecarboxylic acid), have been synthesised and their X-ray structures determined. The complexes are isomorphous, and the metal centres are six-coordinated with two pyridazinyl N atoms, two carboxyl O atoms from two ligands and two water molecules.

Hexaaqua-cobalt(II) 5,5'-(propane-1,3-diyldithio)bis-(1H-tetra-zole-1-acetate).

The asymmetric unit of the title complex, [Co(H2O)6](C9H10N8O4S2), contains one-half of a [Co(H2O)6]2+ cation and one-half of a 5,5′-(propane-1,3-diyldithio)bis(1H-tetrazole-1-acetate) (battp2−) anion. The CoII center is coordinated by six H2O molecules in a distorted octahedral coordination environment. In the crystal structure, intra- and intermolecular O—H⋯O and O—H⋯N hydrogen bonds link the cations and anions into a three-dimensional network. π–π contacts between the tetrazole rings [centroid–centroid distance = 3.346 (1) Å] may further stabilize the structure.