Synthesis of pyrimidine derivatives via multicomponent reaction catalyzed by ferric chloride

An eco-friendly and practical approach was developed for the synthesis of pyrimidine derivatives via a one-pot, three-component coupling reaction of commercially available aldehydes, alkynes, and indazole3/triazole catalyzed by ferric chloride with good to excellent yields. The advantages of this method include environmentally friendly catalyst, easily available materials, and ease of product isolation.     

Shear-induced Precursors of Fibrillar Crystals of Poly(butene-1): A Rheological Study

Chinese Journal of Polymer Science - Strong preshear flow stretches poly(butene-1) chains to form flow-induced precursors of fibrillar crystals. The formation leads to further growth of...     

Synthesis and insecticidal activity of novel 1,2,4-triazole derivatives containing trifluoroacetyl moieties

Molecular Diversity - A series of compounds containing trifluoroacetyl groups were synthesized, and their insecticidal activity against Nilaparvata lugens and Aphis craccivora was evaluated. The...     

一类海-气耦合振子模型行波解的渐近解法

热带海-气振子是一个复杂的自然现象.本文是对一个海-气耦合振子模型,利用一个待定系数和摄动理论相结合的新方法,得到了相应模型的行波渐近解.     

5-溴水杨基荧光酮-曲拉通x-100-羟丙基-β-环糊精荧光猝灭法测定痕量锰

在羟丙基-β-环糊精(HP-β-CD)和曲拉通X-100(Triton X-100)存在下,以NaAc-HAc缓冲溶液为介质,5-溴水杨基荧光酮(5-BrSAF)为荧光试剂,建立了用荧光猝灭法测定痕量锰的新方法.研究了缓冲溶液、显色剂用量、表面活性剂对体系的影响,确定了最佳实验条件.体系的最大激发波长λex=375nm,最大发射波长λex=535nm,Mn2+含量在0.026-3.5μg/25mL范围内与荧光猝灭值△F呈线性关系,方法检出限为1.02μg/L.已用于面粉中锰的测定.     

Using colloid lithography to fabricate silicon nanopillar arrays on silicon substrates

In this study, we partially grafted geminal silanol groups in the protecting organic shells on the surfaces of gold nanoparticles (AuNPs) and then assembled the alkyl-AuNP-Si(OH)(4) particles onto the surfaces of silicon (Si) wafers. The density of assembled AuNPs on the Si surface was adjusted by varying the geminal silanol group content on the AuNP surface; at its optimal content, it approached the high assembly density (0.0254 particles/nm(2)) of an AuNP assembled monolayer. Using reactive-ion etching (RIE) with the templates as masks, we transferred the patterned AuNP assemblies to form large-area, size-tunable, Si nanopillar arrays, the assembly density of which was controlled by the dimensions of the AuNPs. Using this colloidal lithography (CL) process, we could generate Si nanopillars having sub-10-nm diameters and high aspect ratios. The water contact angles of the high-aspect-ratio Si nanopillars approached 150°. We used another fabrication process, involving electron beam lithography and oxygen plasma treatment, to generate hydrophilic 200-nm-resolution line patterns on a Si surface to assemble the AuNPs into 200-nm-resolution dense lines for use as an etching mask. Subsequent CL provided a patterned Si nanopillar array having a feature size of 200 nm on the Si surface. Using this approach, it was possible to pattern sub-10-nm Si nanopillar arrays having densities as high as 0.0232 nm(-2).     

一类大气非线性动力热力学反应-扩散系统解的稳定性态

研究了一类大气非线性系统. 利用大气非线性热力动力学理论, 讨论了大气非线性强迫耗散系统的速度、温度和湿度所满足的非线性反应-扩散系统, 再利用微分方程Lyapunov稳定性理论, 得到了大气非线性反应-扩散系统在均匀定态解邻域内的微扰解. 最后由系统的控制参数的变化, 得到了大气非线性强迫耗散系统有关的物理量的有序-无序-有序状态的转化过程, 从而可以预报和预测相应的局部大气非线性强迫耗散系统的稳定性态.     

Effect of the linkage position in ruthenium dyes on the photoelectrochemical perfomance

A series of newly designed Ru-dyes constructed with [Ru(bpy)(bpp)Cl]⁺ (bpp?=?2,6-bis(N-pyrazolyl)pyridine, bpy?=?bipyridine) as template were evaluated by studying the frontier molecular orbital energy, charge distribution, absorption spectrum, light harvesting efficiency, as well as photogenerated current density by using (time-dependent) density functional theory. The calculation results reveal that the light harvesting efficiency and current density are enhanced with only one linkage group attached onto the 4 site of pyridine ligand. Mounting the linkage groups to 3 or 3′ position on pyridine ligand introduces super strong UV absorption.     

Preparation and Characterization of Uranium–Iron Triple-Bonded UFe(CO)3− and OUFe(CO)3− Complexes

We report the preparation of UFe(CO)₃⁻ and OUFe(CO)₃⁻ complexes using a laser-vaporization supersonic ion source in the gas phase. These compounds were mass-selected and characterized by infrared photodissociation spectroscopy and state-of-the-art quantum chemical studies. There are unprecedented triple bonds between U 6d/5f and Fe 3d orbitals, featuring one covalent σ bond and two Fe-to-U dative π bonds in both complexes. The uranium and iron elements are found to exist in unique formal U(I or III) and Fe(−II) oxidation states, respectively. These findings suggest that there may exist a whole family of stable df–d multiple-bonded f-element-transition-metal compounds that have not been fully recognized to date.     

一类广义飞秒脉冲激光对纳米金属传导模型的同伦解法

研究了一类飞秒脉冲激光对纳米金属薄膜传导模型.首先求出一个特殊模型的精确解析解,然后利用泛函同伦映射理论和方法,得到了相应模型的任意次近似解析解.最后论述了解的意义.