We have used positron annihilation spectroscopy to study the introduction and recovery of point defects in electron-irradiated n-type ZnO. The irradiation Eel=2 MeV, fluence 6 1017cm−2 was performed at room temperature, and isochronal annealings were performed from 300 to 600 K. In addition, monochromatic illumination of the samples during low-temperature positron measurements was used in ident...

The title complex, [ZnBr(2)(C(7)H(6)N(4))](n), was formed under hydro-thermal conditions using the ligand 4-(3-pyrid-yl)-4H-1,2,4-triazole (L). The unique Zn(II) ion is coordinated by one triazole N atom, one pyridine N atom and two Br atoms in a slightly distorted tetra-hedral coordination environment. Symmetry-related Zn(II) ions are connected by bridging L ligands into chains parallel to [00...

This review focusses on two questions: (1) How can the intracellular toxicity of ions such as Ca 2 + or Zn 2 § be reconciled with their extracellular benefit? (2) Why is the dietary requirement for Zn 2 § so high when its documented biological role is that of a tightly-bound prosthetic group of certain enzymes? An answer to both questions is provided by the observation that extracellular cation...

In the title compound, [Zn(N(3))(2)(C(10)H(9)N(3))](n), tetra-hedrally coordinated Zn(II) ions with two monodentate azide ligands are linked into zigzag one-dimensional chain motifs by di-4-pyridylamine (dpa) tethers. Individual [Zn(N(3))(2)(dpa)](n) chains are connected into supra-molecular layers via N-H⋯N hydrogen bonding between the central amine groups of the dpa ligands and terminal unlig...

The electron capture dissociation (ECD) and collision-induced dissociation (CID) of complexes of polyamidoamine (PAMAM) dendrimers with metal ions Ag(+), Cu(2+), Zn(2+), Fe(2+), and Fe(3+) were determined by Fourier transform ion cyclotron resonance mass spectrometry. Complexes were of the form [PD + M + mH](5+) where PD = generation two PAMAM dendrimer with amidoethanol surface groups, M = met...

Achillea tenuifolia Lam. (Asteraceae) afforded a dichloromethane fraction from which three known compounds β-sitosterol (compound1), 5-hydroxy, 4',6,7– trimethoxy flavone (salvigenin compound 2), and methyl-gallate (compound 3) were isolated for the first time. The structure of isolated compounds was elucidated by different spectroscopic methods. Applying the molar-ratio method, the complexat...

In the title compound, [Zn(C(10)H(14)O(4))(C(4)H(6)N(2))](n), each Zn(II) ion is coordinated by one N atom from one 2-methyl-1H-imidazole ligand and three O atoms from two camphorate (cap) ligands in a distorted tetra-hedral geometry. In one of the cap ligands, one methyl group is disordered between positions 1 and 3 in a 0.518 (12):0.482 (12) ratio. Each cap ligand bridges three Zn(II) ions, f...

In the title coordination polymer, {[Zn(C(8)H(5)NO(4))(C(3)H(4)N(2))]·0.25H(2)O}(n), the Zn(2+) cation has an N(2)O(2) donor set involving two carboxyl-ate O atoms from two 5-amino-isophthalate anions, one N atom from a 5-amino-isophthalate anion, and one imidazole N atom displaying a slightly distorted tetra-hedral geometry with two additional O-atom neighbours, with Zn-to-ligand distances of ...

Metal contamination of water is a serious challenge faced by environmental chemists, but there is also economic value in the removal of metals for recycling or extraction. Our prior observation that hydroxyfullerenes [C60O(x)(OH)y](n-) act as chelate agents to Fe(3+) suggests that these material, or derivatives, may be used for co-precipitation. We report the removal of main group (Al(3+), Ag(+...

The atomic level mechanism of incorporation of Zn(2+) into hydroxyapatite (HAp), which is a potential dopant to promote bone formation, was investigated, based on first principles total energy calculations and experimental X-ray absorption near edge structure (XANES) analyses. It was found that Zn(2+)-doped HAp tends to have a Ca-deficient chemical composition and substitutional Zn(2+) ions are...