Reductive Dehalogenation of Arylhalides and Alkylhalides with Zinc in THF Saturated Aqueous Ammonium Chloride

A low‐cost and highly effective zinc/THF‐saturated aqueous ammonium chloride has been developed for dehalogenation of arylhalides and alkylhalides in aqueous systems.     

Ammine Complexes of Na‐, Ag‐, Mn‐, and Zn‐Azides

The synthesis of ammine metal azides is achieved through a simple route in liquid ammonia solution. Azides of silver, sodium, manganese, and zinc were obtained as ammine complexes from liquid ammonia and the solid compounds were characterized. The NH₃ solutions were investigated by means of NMR spectroscopy as well. The triamminesilver(I) azide as well as the unusual tetraamminesilver(I) and pentaamminesodium(I) azides are presented. The structures of the hexaamminemanganese(II) and hexaamminezinc(II) azides, which crystallize with four ammonia molecules of solvation, are elucidated. From these compounds the binary azides Mn(N₃)₂ and Zn(N₃)₂ were obtained by (careful) heating.     

Crystal structures and spectroscopic properties of a new zinc phosphite cluster and an unexpected chainlike zinc phosphate obtained by hydrothermal reactions

A new zinc phosphite cluster, Zn₂(4,4′-dmbpy)₂(H₂PO₃)₄1, and a new chainlike zinc phosphate, Zn₂(5,5′-dmbpy)₂(HPO₄)(H₂PO₄)₂2, have been synthesized under hydrothermal conditions (4,4′-dmbpy=4,4′-dimethyl-2,2′-dipyridy, 5,5′-dmbpy=5,5′-dimethyl-2,2′-dipyridy). Compound 1 is a molecular zinc phosphite constructed from ZnO₃N₂ trigonal bipyramids, H₂PO₃ pseudo-pyramids and 4,4′-dmbpy ligands. Compound 2 possesses a 1D chainlike framework constructed from ZnO₃N₂ trigonal bipyramids, HPO₄ tetrahedra, H₂PO₄ tetrahedra and 5,5′-dmbpy ligands. Both compounds 1 and 2 exhibit intensive photoluminescence originated from the intraligand π-π* transitions. Crystal data: 1, monoclinic, P2₁/n, , , , β=110.857(3)°, , Z=2, R1=0.0297, wR₁=0.0801; 2, triclinic, P-1, , , , α=64.995(9)°, β=65.952(9)°, γ=65.296(8)°, , Z=2, R₁=0.0418, wR₁=0.1010.     

A Novel Two‐dimensional Coordination Polymer based on Rhombic Tetrameric Subunit Zn4O4 as Building Block

Hydrothermal reaction of olsalazine sodium, phenanthroline and Zn(ClO₄)₂·6H₂O in the presence of water and ethanol affords a two‐dimensional coordination polymer [Zn₄(OSA)₃(Phen)₂(H₂O)₂]_n ( 1 ) (OSA = olsalazine) which is characterized by single X‐ray determination, IR and UV spectrum. The local coordination around all zinc ions can be best described as a slightly distorted triangle bipyramid. Complex 1 consists of a tetrameric subunit, which is made up of four Zn atoms bridged by four O atoms. Two types of osalazine ligands can be found in the complex according to their different coordination modes of carboxyl groups. Crystal data for 1 : , a = 10.087(7), b = 12.830(9), c = 14.545(11) Å, α =114.598(10)°, β = 92.552(10)°, γ = 108.515(10)°, V = 1588(2) ų, Z = 2, R1 = 0.0818, wR2 = 0.1855. In comparison with the free ligand, the UV spectrum of 1 in solution (H₂O: EtOH = 1:1) shows a small Einstein shift probably due to the formation of coordination polymer and supramoleculer hydrogen‐bonding interactions.     

Synthesis and solvent effects on the electronic absorption and fluorescence spectral properties of substituted zinc phthalocyanines

The synthesis and spectroscopic properties of the following tetra- and octa-substituted aryloxy zinc(II) phthalocyanines are reported for the first time: 1,(4)-(tetrabenzyloxyphenoxyphthalocyaninato) zinc(II) (7); 2,(3)-(tetrabenzyloxyphenoxyphthalocyaninato) zinc(II) (8); 2,3-(octabenzyloxyphenoxyphthalocyaninato) zinc(II) (9). The new compounds have been characterized by elemental analysis, IR, ¹H NMR spectroscopy and electronic spectroscopy. Spectroscopic properties of these compounds were investigated in different solvents. Protonation of non-peripherally substituted complex 7 resulted in the splitting and red-shifting of the Q-band. The peripherally substituted derivatives 8 and 9, did not show the split in the Q-band. Fluorescence spectra of the derivatives show Stokes shifts typical of MPc complexes.     

Isovalent vs. aliovalent transition metal doping of zinc oxide lithium-ion battery anodes — in-depth investigation by ex situ and operando X-ray absorption spectroscopy

The precise determination of de-/lithiation mechanisms in alternative lithium-ion battery electrode materials is crucial for their potential future success, but quite challenging — e.g., due to the occurrence of multiple crystalline and (frequently) amorphous phases. Herein, we report an in-depth ex situ/operando characterization of (carbon-coated) Fe- and Co-doped zinc oxide anodes via X-ray absorption spectroscopy to probe the oxidation state and local structural environment of the different metals upon de-/lithiation. The results provide fundamental insights into the mechanism of the conversion and alloying reaction taking place for these two active materials. In addition, this comparative investigation allows for an evaluation of the impact of isovalent (Co²⁺) and aliovalent (Fe³⁺) doping on the lithiation mechanism, having an impact on the initial lithiation kinetics, while both dopants generally enable a greatly increased re-oxidation of zinc compared to pure zinc oxide and, thus, a more reversible conversion reaction.     

Nickel ferrite/zinc oxide nanocomposite: Investigating the photocatalytic and antibacterial properties

A facile strategy was used for the synthesis of nickel ferrite/zinc oxide (NiFe₂O_4/ZnO) nanocomposite via an ultra-sonication method and observed its recyclability and photostability with enhanced visible light-driven photocatalytic performance. The photo degradation activities of as-synthesized photocatalysts were investigated using various dyes including methylene blue, crystal violet and methyl orange under solar light irradiation. Prepared material degrades 49.2% methyl orange, 44.4% methyl blue and 41.3% crystal violet in 40 min. Further, the synergistic effect of nickel ferrite and zinc oxide can reduce the probability of recombination of charge carrier and boost the charge separation which leads to remarkable photocatalytic performance. Magnetic properties of nickel ferrite reduces the agglomeration of material and increases the recyclability. The NiFe₂O_4/ZnO nanocomposites also exhibited better antibacterial activity for Pseudomonas aeruginosa and Staphylococcus aureus, which shows that they can be used for both environmental and biological applications.     

A highly sensitive fluorescent probe for tracking intracellular zinc ions and direct imaging of prostatic tissue in mice

A highly sensitive fluorescent sensor ZnDN was designed, synthesized and used for tracking intracellular zinc ions in various living cells and direct imaging of prostatic tissue in mice. ZnDN was prepared from the heterocyclic-fused naphthalimide fluorophore, and the zinc receptor, N,N-bis(2-pyridylmethyl)ethyl-enediamine (BPEN). Upon addition of Zn²⁺ to the solutions of ZnDN, a remarkable fluorescence enhancement was observed, which could be attributed to the photo-induced electron transfer (PET) mechanism. Since ZnDN exhibited high sensitivity toward Zn²⁺ in phosphate buffer solution, with a limit of detection of 4.0×10^-9 mol/L, it was further applied for the imaging of exogenous and endogenous Zn²⁺ in different living cells. Living cells imaging experiments suggested that ZnDN could image the changes of intracellular free zinc ions, and could be used for two-photon imaging. Moreover, flow cytometry suggested that ZnDN could distinguish cancerous prostate cells from normal cells. Animal experiments indicated that ZnDN had the potential in imaging prostate tissue in vivo.     

Photophysical insights on quantum dots-zinc porphyrazine system studied in solution

The present study reports spontaneous interaction of a quantum dots, namely, CdS_xSe_1-x/ZnS (QD) with zinc porphyrazine (1) in toluene. It is observed from steady state fluorescence measurements that photoluminescence of QD suffers quenching by 1. Time resolved fluorescence measurements reveal small change in the lifetime of QD (16.10 ns) following it interaction with 1 (15.77 ns). The magnitude of k_q for QD-1 system, i.e., k_q ​= ​5.25 ​× ​10¹² ​L⋅mol⁻¹⋅sec⁻¹ (evaluated from the stern-volmer plot) establishes that photoexcited QD undergoes decay by 1 according to static quenching mechanism. The results emerging from above study confirm that QD-1 system may be judiciously applied as an energy storage material in near future.     

不同维度ZnO能带结构和电子态密度的研究

本文采用基于密度泛函理论的第一性原理计算方法来研究不同维度ZnO的能带结构和电子态密度.参考实验上的ZnO晶格参数构建不同维度的ZnO模型并进行结构优化后再计算能带结构和电子态密度.研究结果表明二维和三维ZnO都属于直接带隙半导体且二维ZnO的禁带宽度大于三维ZnO;从三维变到二维,ZnO的电子局域化程度变高且Zn 3d轨道电子从能量较低的能级向能量较高的能级跃迁.本文的研究展示了二维和三维ZnO能带结构和电子态密度的异同,为二维ZnO基的器件研究提供了一定的理论参考价值.