Condensation of ethyl phenylpropiolate with some cyanoacetyl and cyanomethylene heterocycles

N-Cyanoacetyl pyrrolidine, piperidine and morpholine reacted with ethyl phenylpropiolate to give the rearranged Michael addition products III. Some interesting results obtained from the bromination, hydrolysis and reduction of III are reported. 2-Thiophene and 2-furaneaceto-nitriles reacted with ethyl phenylpropiolate to give the Claisen addition products XVIII. Reaction of either III or XVIII with hydrazine hydrate, phenylhydrazine and hydroxylamine hydrochloride afforded 3-phenylpyrazol-5-one, 1,3-diphenylpyrazol-5-one and 3-phenylisoxazol-5-one together with the appropriate starting cyanoacetyl or cyanomethylene compounds, respectively. The mechanism for the formation of the various reaction products beside the ir and nmr spectral results are discussed.     

Reactions with heterocyclic amidines. VI. Synthesis and chemistry of pyrazol-5-yl,and 1,2,4-triazol-5-ylhydrazonyl chlorides

The 4-bromo-3-phenylpyrazol-5-ylhydrazonyl chlorides (Ia,b) and 1,2,4-triazol-5-ylhydrazonyl chlorides (IIa,b) were prepared via coupling of diazotized 4-bromo-3-phenyl-5-aminopyrazole (III) and 5-amino-1,2,4-triazole (IV) with α-chloro derivatives of acetylacetone and of ethyl aceto-acetate. Compounds Ia and IIa,b were utilised for the synthesis of several new heterocyclic derivatives.     

Dipolar interactions and origin of spin ice in ising pyrochlore magnets

Recent experiments suggest that the Ising pyrochlore magnets Ho2Ti2O7 and Dy2Ti2O7 display qualitative properties of the nearest-neighbor "spin ice" model. We discuss the dipolar energy scale present in both these materials and discuss how spin-ice behavior can occur despite the presence of long-range dipolar interactions. We present results of numerical simulations and a mean field analysis of Ising pyrochlore systems. Based on our quantitative theory, we suggest that the spin-ice behavior in these systems is due to long-range dipolar interactions, and that the nearest-neighbor exchange in Dy2Ti2O7 is antiferromagnetic.     

Pristine and supported ZnO-based catalysts for phenazopyridine degradation with direct solar light

In search for safe techniques to manage waste pharmaceutical compounds drained in water, solar-driven degradation of phenazopyridine (a model drug) was investigated in aqueous media using different ZnO-based catalyst systems. Naked ZnO, CdS-sensitized ZnO (ZnO/CdS) and activated carbon-supported ZnO (AC/ZnO) have been studied. Both naked ZnO and AC/ZnO were highly efficient in mineralizing phenazopyridine, reaching complete removal in ～50 min, with AC/ZnO having the higher edge. The ZnO/CdS system showed lower efficiency, due to screening of light by CdS. Moreover, the tendency of CdS to leach out Cd²⁺ ions discouraged the use of CdS as sensitizer in this work. In both ZnO and AC/ZnO systems, the photo-degradation reaction was induced by the UV tail of the solar light. The visible region, with wavelength longer than 400 nm, failed to induce photo-degradation. The reaction was faster with higher catalyst loading, until a maximum efficiency was reached at a certain concentration. The rate of reaction increased with higher drug concentrations up to a certain limit. The effect of pH value was studied, and the catalysts showed highest efficiencies at pH close to 7. Stability of ZnO to degradation was studied. Both catalyst systems showed lowered efficiencies on recovery and reuse. The results suggest that complete mineralization of waste drugs, commonly dumped in sewage water, with direct solar light is a potentially feasible strategy using the AC/ZnO catalyst.     

Experiments on the sputtering of neutral Cu2 dimers from Cu by Ar+ ions (60–300 eV)

A planar polycrystalline copper target was bombarded normally by Ar⁺ ions with energies ranging from 60 to 300 eV. in the source of a mass spectrometer. The neutral particles sputtered normally from the target were post-ionized and analyzed in the mass spectrometer. A thermionically sustained, magnetically confined low pressure arc plasma was used to supply the bombarding ions, and for post-ionization of the neutral sputtered species. It was found that the relative yields of the sputtered neutral post-ionized Cu₂ dimers are linearly proportional to S², where S is the total sputtering yield for Ar⁺ -Cu. The results support the recombination model for the formation of neutral dimers in sputtering.     

配合物(BenzMeIm)2[PtCl4]的合成与表征

通过离子液体氯化1-苄基-3-甲基咪唑（BenzMeIm-Cl）与PtCl₂的反应,合成了配合物（BenzMeIm）₂[PtCl₄],并用元素分析、红外光谱、紫外-可见光谱、¹H NMR、¹³C NMR和单晶X射线衍射对其进行了表征。单晶X射线分析表明,配合物结构属于P2₁/c空间群,晶胞参数和结构解析参数为：a=0.981 80（5）nm,b=0.861 47（3）nm,c=0.144 332（7）nm,β=92.480（2）°,V=121.96（1）nm³,R₁=0.014 4,wR₂=0.038 8。     

Kinetics and mechanisms of oxidation of 1-octene and heptanal by crown ether-solubilized potassium permanganate in non-aqueous solvents

The kinetics of oxidation of 1-octene and heptanal by 18-crown-6-ether-solubilized KMnO₄ in benzene and CH₂Cl₂ have been investigated. In benzene, the oxidation of 1-octene is first order with respect to the oxidant and zero order with respect to the substrate, whereas in CH₂Cl₂ the reaction is first order with respect to both substrate and oxidant. The reaction of heptanal followed different kinetics being first order with respect to both substrate and oxidant, regardless of whether benzene or CH₂Cl₂ was employed as the solvent. The values of activation energy E _a, standard enthalpy H ^*, standard entropy change S ^*, and standard free energy G ^*, for the reaction, are reported. Mechanistic pathways for the studied reactions are also proposed.     

A study of some quinolizone derivatives

The condensation of methyl 2-pyridylacetate and ethyl phenylpropiolate has been found to be a simple and convenient method for the preparation of 4-quinolizone derivatives. Upon hydrolysis and decarboxylation, the initial condensation product, l-carbethoxy-2-phenyl-4H-quinolizin-4-one (V) was converted to 2-phenyl-4H-quinolizin-4-one (VII). Nitration and bromination of these quinolizones were affected under mild conditions. Nitration of V displaced the carbethoxy group, while bromination did not and 1,3-dinitro-4H-quinolizin-4-one and 1-carbeth-oxy-2-phenyl-3-bromo-4H-quinolizin-4-one were obtained, respectively.     

菲啶和三苯基膦的Cu(Ⅰ)/Cu(Ⅱ)配合物的合成、表征和X射线晶体结构分析

以三苯基膦（PPh₃）为共配体,合成了2种新的铜（Ⅰ）和铜（Ⅱ）与菲啶（Phend）的配合物,其组成为[Cu（κ¹-Phend）₂Cl₂]（1）和[Cu₂（κ¹-Phend）₂（κ¹-PPh₃）₂（μ-Cl）₂]（2）。这些配合物的结构通过元素分析、摩尔电导率、FT-IR、UV-Vis和单晶X射线衍射进行了研究。典型配合物1的X射线衍射分析显示,Cu（Ⅱ）配位构型为扭曲的平面四方形,而双核配合物2的Cu（Ⅰ）中心为含μ-Cl^-离子的不规则四面体构型。FT-IR谱、元素分析以及UV-Vis谱证实了它们的成分、几何形状和配体相互作用。2种配合物的结构通过密度泛函理论（DFT）计算进行了优化,以解释电子光谱特性。