Highly fluorous zirconocene(IV) complexes and their catalytic applications in the polymerization of ethylene

The catalytic activities of the highly fluorous systems formed by the zirconocene(IV) complexes [Zr{η⁵-C₅H₄SiMe₂C₂H₄R_F}₂Cl₂] (R_F = C₆F₁₃ (4a), C₁₀F₂₁ (4b)) or [Zr-{η⁵-C₅H₃(SiMe₂C₂H₄C₆F₁₃)₂}₂Cl₂] (5a) and MMAO in toluene have been studied and compared with analogous nonfluorous systems generated from [Zr{η⁵-C₅H₄SiMe₃}₂Cl₂] and [Zr{η⁵-C₅H₅}₂Cl₂]. Although less active than the reference systems, the fluorous catalysts are stable over prolonged polymerization times, giving rise to polymers with similar molecular weights to those obtained with [Zr{η⁵-C₅H₄SiMe₃}₂Cl₂].     

铑(Ⅲ)催化N-磺酰基2-甲酰苯胺与烯烃环化制备(2H)喹啉(英文)

开发了一种用铑(III)催化的N-磺酰基2-氨基苯甲醛与烯烃环化生成喹啉衍生物的方法,得到较高产率的喹啉衍生物,并且在反应条件下,反应具有较好的官能团兼容性.这是首次运用铑(III)作为催化剂合成烷基1-磺酰基-1,2-二氢喹啉-3-羧酸酯.该催化体系表现较好的催化性且反应操作较为简单.     

Preparation and Application of Fullerene C60‐Polymers in Piezoelectric Quartz Crystal Sensors for Hemoglobin and Olefins

The C60—polycinnamaldehyde (C₆₀—PCA) and C60—polyphenylacetylene (C60—PPA) polymers were synthesized by the Friedel—Craft reaction and applied as piezoelectric (PZ) quartz crystal coating materials. A C60—polycinnamaldehyde (PCA) coated piezoelectric quartz crystal liquid sensor with a homemade computer interface was prepared and applied as a PZ hemoglobin sensor. The adsorption of hemoglobin onto the C60—PCA coated crystal resulted in a decreased oscillating frequency. The variations in crystal frequency were converted to voltage with a frequency to voltage converter, followed by amplification with OPA and data acquisition with an analog to digital converter. The PZ hemoglobin sensor exhibited good sensitivity of 6530 Hz/(mg/mL) with a detection limit at the ppm level for hemoglobin. Further, a C60—polyphenylacetylene (C60—PPA) coated piezoelectric quartz crystal gas sensor with an Intell‐8255 data processing system for various olefin vapors was also made. The aromatic hydrocarbons such as toluene seem to have greater adsorption onto C60—PPA membrane than alkynes, alkenes, and alkanes. The adsorption of polycyclic aromatic hydrocarbons (PAHs) onto the C60—PPA membrane was also examined. The C₆₀—PPA coated PZ crystal gas sensor showed much better sensitivity for PAHs than for other olefins such as toluene, 1‐hexyne and 1‐hexene, and a much larger frequency shift for naphthalene than other PAHs was also found.     

Non-covalently dendronized flavins as organocatalysts for aerobic reduction of olefins

A variety of association complexes of synthetic flavin with diaminopyridine and melamine receptors are described in terms of synthesis, association properties, and catalytic activities for aerobic hydrogenation of olefins. The 1:1 association complex of lumiflavin 1 with 2,6-bis(acylamino)pyridine receptor bearing 3,4,5-trialkoxybenzyl ether dendron unit 2 acts as an efficient supramolecular organocatalyst for the aerobic reduction of styrene at ambient temperature under atmospheric air pressure.     

Ultrasound-Assisted Epoxidation of Olefins and α,β-Unsaturated Ketones over Hydrotalcites Using Hydrogen Peroxide

Abstract

An efficient ultrasound-assisted epoxidation of olefins and α,β-unsaturated ketones over hydrotalcite catalysts in the presence of hydrogen peroxide and acetonitrile is described. This general and selective protocol is relatively fast and is applicable to a wide variety of substrates.     

高密度聚乙烯共混调控烯烃嵌段共聚物拉伸性能

通过熔融共混法制备了高密度聚乙烯(HDPE)与烯烃嵌段共聚物(OBC)的共混物,研究了HDPE含量对共混体系结晶和拉伸行为的影响.实验结果表明,共混物熔体存在相分离.结晶时两组分互相影响,出现共结晶现象.共混物具有优异弹性回复与高断裂伸长率,而拉伸模量与断裂强度随着HDPE含量增加而逐渐增大.借助Slip-link橡胶弹性理论对应力应变曲线进行了分析,发现拉伸曲线可以很好的用理论模型进行拟合.将共混物的微观结构变化同模型参数进行了对比,建立了共混物结构和性能的有效关联.     

The influence of N-heterocyclic carbene steric and electronic properties in Ru-catalysed cross metathesis reactions

The present study examines the influence of N-heterocyclic carbene (NHC) ligand electronic and steric parameters on the activity of ruthenium indenylidene complexes in cross metathesis. The NHC ligands tested lead to varied E/Z selectivities with the pre-catalyst bearing an IMes ligand exhibiting high activity.