جستجوی مقالات مرتبط با کلیدواژه "zinc (ii)" در نشریات گروه "شیمی"

In this paper, we report the syntheses and crystal structuredetermination of three mononuclear and four-coordinated zinc(II) bromide complexes with chemical formula of [Zn(tsc)2]Br2 (1), Zn(PPh3)2Br2 (2) and Zn(Brcatsc)Br2 (3). The synthesized complexes are characterized by elemental analysis (CHN) and theircrystal structures are investigated by single crystal X-ray diffraction. In complex 1, the TSC coordinates to the zinc(II) ion as a bidentate ligand via N and S atoms. In complex 3, the thiosemicarbazone ligand Brcatsc coordinates to zinc(II) ion as a monodentate ligand via S atom. In these complexes, the zinc(II) ion coordinated in a distorted tetrahedral coordination geometry.

Hollow fiber-solid phase microextraction (HF-SPME) technique containing multiwalled carbon nanotubes (MWCNTs) reinforced sol-gel nanocomposite coupled with UV–Vis spectrophotometry was applied for preconcentration and determination of lead, zinc and silver in water samples. In this technique, a high efficiency sorbent containing mixture of MWCNTs and a microporous gel was injected into a piece of a polypropylene hollow fiber for in situ gelation. The method validation was included and satisfying results were obtained. It owes large surface area and porosity of the nano-adsorbent. Under the optimal conditions, linear calibration curves were established for the concentration of Pb2+, Zn2+ and Ag+ in the range of 0.2–7.0, 0.3–7.0 and 2.0–50 µg/mL respectively. The limits of detection were 0.032, 0.057 and 0.325 µg/mL for Pb2+, Zn2+ and Ag+. The relative standard deviations (RSDs) were found to be less than 8.0 %.

Metal-Organic Frameworks (MOFs) represent a new class of highly porous materials. On this regard,  two nano porous metal-organic frameworks of [Zn2(1,4-bdc)2(H2O)2∙(DMF)2]n (1) and [Zn2(1,4-bdc)2(dabco)]·4DMF·1⁄2H2O (2), (1,4-bdc = benzene-1,4-dicarboxylate, dabco = 1,4-diazabicyclo[2.2.2]octane and DMF = N,N-dimethylformamide) were synthesized and characterized. They were used for preparation of ZnO nanomaterials. With calcination of 1, agglomerated ZnO nanoparticles could be fabricated, but by the same process on 2, the tendency of ZnO nanoparticles to agglomeration was decreased. In addition, the ZnO nanoparticles prepared from compound 2 had smaller diameter than those obtained from compound 1. In fact, the role of organic dabco ligands in 2 is similar to the role of polymeric stabilizers in formation of nanoparticles. Finally, considering the various applications of ZnO nanomaterials such as light-emitting diodes, photodetectors, photodiodes, gas sensors and dye-sensitized solar cells (DSSCs), it seems that preparation of ZnO nanomaterials from their MOFs could be one of the simple and effective methods which may be applied for preparation of them.