Controlled synthesis of ZnO nanoparticles from a Zn(II) coordination polymer: Structural characterization,optical properties and photocatalytic activity

A zinc coordination polymer derived from pyridine-2,6-dicarboxylate (PDC), {[Zn₂(PDC)₂]}_n, was successfully prepared via conventional, sonication and microwave-irradiation methods. The composition and characteristics of the obtained coordination polymers (CPs) were investigated by elemental analysis, TGA/DTA, X-ray diffraction and spectroscopic techniques. The so obtained CPs were heat-treated in the air at 600 °C for 2 h to produce ZnO of nanosized particles (NPs). It is of interest to note that the synthesis approach of the precursor greatly affects both the nanoparticle size and the structure of the resulting ZnO NPs. Moreover, the smallest particle size was associated with the sample derived from the ultrasonically prepared precursor. TEM analysis revealed that all samples have sphere-like morphologies. Structural analysis of the prepared ZnO samples was conducted and compared using Rietveld analysis of their PXRD patterns. Optical band gap calculations based on analysis of the UV–vis spectra of ZnO samples using Tauc's power law were achieved. The highest band gap of 3.63 eV was observed for ZnO sample obtained from the ultrasonically prepared precursor. Furthermore, the photocatalytic activity of ZnO NPs for the removal of Eosin Y color was monitored. The highest removal efficiency was recorded for ZnO originated from the ultrasonically synthesized precursor. Enhancement of removal efficiency that reached 98% was attained in only a period of 8 min. Its recycling test showed that it can be reused without structural changes over four cycling experiments.     

一种水相脱卤催化剂的红外光谱解析

水相脱卤催化剂PVP-PdCl2-MnCl2/GLM-PEG400,用于催化难溶于水的芳香卤化物水相脱卤,对芳香卤化物呈现出高的脱卤活性.通过IR光谱表征探讨了催化剂各组分在催化脱卤中的作用.     

Synthesis of 2-substituted indoles by palladium-catalyzed heteroannulation with Pd-NaY zeolite catalysts

Various 2-substituted indoles were prepared by heteroannulation of o-iodoanilines and terminal alkynes in a one-pot reaction with a Pd(II)-NaY zeolite catalyst. The product formation largely depended on the solvent, base, and reaction temperature. The recycled catalyst showed good reusability in the heteroannulation reaction.     

A New Two‐Dimensional Coordination Polymer of Mercury(II) with very High Thermal Stability

A 2D Hg^II coordination polymer containing ligands 1,2,4‐triazole (Htrz) and thiocyanate, [Hg(μ₃‐trz)(SCN)]_n ( 1 ) has been synthesized and characterized by elemental analysis and IR spectroscopy. The single‐crystal X‐ray data show the coordination number of Hg atoms is four and the ligand trz^? acts as a three‐fold donor. The thermal stability of compound 1 was studied by thermal gravimetric and differential thermal analyses. The composition and formation of the complex in methanol solution were found to be in support of its solid state structure.     

Synthesis and applications of chiral bis-THF in asymmetric synthesis

The synthesis of enantiopure bis-THF is described, starting from d-mannitol. Bis-THF is used as chiral ligand for organolithium reagents in four different reactions. The enantioselectivity provided by this ligand is moderate, and the asymmetric induction is in line with the expected model.     

Applications of fast atom bombardment mass spectrometry (FAB MS) to organometallic and coordination chemistry

This article describes the technique of fast atom bombardment mass spectrometry (FAB MS) and its applications to the analysis of organometallic and coordination complexes. Sections on ion generation and matrices are followed by a Periodic Group-based review of FAB MS results obtained from Transition Metal and Main Group compounds, organometallic cluster carbonyls and their derivatives, and salts of poly-oxo-anions. The literature has been surveyed from 1981 to approximately mid-1986.     

Strained silacycle-catalyzed asymmetric Diels-Alder cycloadditions: the first highly enantioselective silicon Lewis acid catalyst

The first highly enantioselective silicon Lewis acid catalyst for an asymmetric organic transformation has been developed. The catalyst derives its activity from the strain induced in the silicon center by virtue of being constrained in a five-membered ring. A simple tridentate ligand has been developed and the derived chlorosilane complex catalyzes the Diels-Alder cycloaddition of methacrolein and cyclopentadiene with 94% ee.     

正交实验设计法研究ZSM-5催化剂的积炭量

用NaOH溶液吸收法研究了ZnNiZSM-5芳构化催化剂的积炭量,用色谱纯二氧化碳考察了此方法的准确度.用热失重法确定了烧炭的最佳温度为570℃,根据实验确定了烧炭时间为7h,空气流量为120mL/min.采用正交实验设计法对影响芳构化催化剂积炭量的温度、空速、高径比进行了研究.通过实验结果可知,积炭量最少的最佳工艺条件是温度为560℃,空速为1. 5h-1,高径比为6.1.     

12-Ring Network Coordination Polymer——{[Cu(C_4N_2H_(10))_4]_2·H_4V_4O_(14)}_n Formed by Linking cyclo-[H_4V_4O_(14)]~(4-) with Cu(C_4N_2H_(10))~(2+)_4 Cation Clusters

IntroductionThe interest in polyoxometalates that are widelyused in medical chemistry, catalyst reactions, and ma-terial sciences stems from their complicated aggregatesformed by means of corner-, edge- and face-sha-ring[1—4]. The exploitation of new str…     

Catalytic air oxidation of ambient temperature hydrocarbons

Catalytic air oxidation of the aliphatic hydrocarbons n-decane, hexanes, gasoline and diesel fuel was conducted at ambient temperature with novel iron catalysts. The concentration of n-decane in water was reduced from 1.42 g in 100 ml to 0.07 g in 100 ml in 5 h at room temperature forming carbon monoxide and water by means of intermediate aldehydes. Results of FT–IR and GC–MS analyses demonstrated formation of aldehydes and unsaturated alcohols. Carbon monoxide was detected on catalyst residues and in the vapor phase. The indicated catalytic reaction mechanisms are discussed.