Transition metal compound, catalyst composition comprising same, and method for producing olefin polymer using same
申请人:LG CHEM, LTD.
公开号:US10280238B2
公开(公告)日:2019-05-07
The present invention provides a transition metal compound, a catalyst composition comprising the same, and a method for producing an olefin polymer using the catalyst composition, the transition metal compound being capable of exhibiting high activity in olefin polymerization reaction, and also being capable of easily controlling the physical properties of an olefin polymer. When the transition metal compound is used, it is possible to provide an olefin polymer having an excellent energy-saving effect at the time of processing or molding.
Fine Tuning of the Rotary Motion by Structural Modification in Light-Driven Unidirectional Molecular Motors
作者:Javier Vicario、Martin Walko、Auke Meetsma、Ben L. Feringa
DOI:10.1021/ja058303m
日期:2006.4.1
The introduction of bulky substituents at the stereogeniccenter of light-driven second-generation molecular motors results in an acceleration of the speed of rotation. This is due to a more strained structure with elongated C=C bonds and a higher energy level of the ground state relative to the transition state for the rate-limiting thermal isomerization step. Understanding the profound influence
Increased Speed of Rotation for the Smallest Light-Driven Molecular Motor
作者:Matthijs K. J. ter Wiel、Richard A. van Delden、Auke Meetsma、Ben L. Feringa
DOI:10.1021/ja036782o
日期:2003.12.1
six-membered rings, but is also applicable to achieve the unidirectional movement for molecular motors having five-membered rings. Although X-ray analyses show that the five-membered rings in the cis- and trans-isomer of the new molecular motor are nearly flat, the energy differences between the (pseudo-)diaxial and (pseudo-)diequatorial conformations of the methyl substituents in both isomers are still
在本文中,我们展示了最小的人造光驱动分子马达,仅由 28 个碳原子和 24 个氢原子组成。通过在空间过度拥挤的烯烃的中心烯键旁边引入立体中心在分子水平上控制旋转运动的方向性的概念不仅适用于具有六元环的分子马达,也适用于实现单向运动具有五元环的分子马达的运动。尽管 X 射线分析表明新分子马达的顺式和反式异构体中的五元环几乎是平的,两种异构体中甲基取代基的(伪)双轴和(伪)双轴构象之间的能量差异仍然大到足以引导分子的一半相对于另一半以顺时针方式旋转。完整的旋转循环包括四个连续的步骤:两个光化学异构化,每个后面跟着一个热螺旋反转。两种光化学顺反异构化都优先考虑不稳定的双赤道异构体而不是稳定的双轴异构体。与其六元环类似物相比,这种运动分子的螺旋反转的热障显着降低,最快步骤的半衰期在室温下仅为 18 秒。两个光化学异构化,每个都紧跟一个热螺旋反转。两种光化学顺反异构化都优先考虑不稳定的双赤道异构体而
New procedure for the preparation of highly sterically hindered alkenes using a hypervalent iodine reagent
作者:Matthijs K. J. ter Wiel、Javier Vicario、Stephen G. Davey、Auke Meetsma、Ben L. Feringa
DOI:10.1039/b414959a
日期:——
New methodology is described to construct the olefinic bond in overcrowded alkenes using a hypervalent iodine reagent, and applied in the synthesis of molecular motors.
描述了一种使用高价碘试剂在过度拥挤的烯烃中构建烯烃键的新方法,并将其应用于分子马达的合成中。
Molecular Stirrers in Action
作者:Jiawen Chen、Jos C. M. Kistemaker、Jort Robertus、Ben L. Feringa
DOI:10.1021/ja507711h
日期:2014.10.22
spectroscopy in a variety of solvents with different polarity and viscosity. Quantitative analyses of kinetic and thermodynamic parameters show that the rotary speed is affected by the rigidity of the substituents and the length of the rigid substituents and that the differences in speed are governed by entropy effects. Most pronounced is the effect of solventviscosity on the rotary motion when long