在这里,我们报告了不对称取代的偶氮苯衍生物的合成,一侧具有间烷基取代基,另一侧具有给电子或吸电子基团的间芳基部分。这些分子的热 ( Z ) 到 ( E ) 异构化的半衰期是在正辛烷中测量的,这可以研究它们的取代基之间芳基-烷基相互作用的强度。发现烷基底物的伦敦分散供体强度是观察到的稳定化的决定性因素,而芳基片段的电子结构不会显着影响异构化。
Using solid-state 15N NMR spectroscopy, the cis/trans isomerization in a 2-D array of surface-mounted azobenzene-based switches was detected for the first time. In order to achieve this, a new class of rod-shaped molecular switches, suitable for formation of two-dimensional regular arrays on large facets of tris(o-phenylenedioxy)cyclotriphosphazene (TPP) nanocrystals, was synthesized. A mechanochemical
Attraction or Repulsion? London Dispersion Forces Control Azobenzene Switches
作者:Luca Schweighauser、Marcel A. Strauss、Silvia Bellotto、Hermann A. Wegner
DOI:10.1002/anie.201506126
日期:2015.11.2
entirely repulsive through steric hindrance. Such groups have additional attractive effects arising from weak Londondispersionforces between the neutral atoms. Steric interactions are recognized to have a strong influence on isomerization processes, such as in azobenzene‐based molecular switches. Textbooks indicate that steric hindrance destabilizes the Z isomers. Herein, we demonstrate that increasing
Cyclopentadienyl titanium hydroxylaminato complexes as highly active catalysts for the polymerization of propylene
作者:Andrew P. Dove、Xiangjin Xie、Robert M. Waymouth
DOI:10.1039/b418778d
日期:——
Half sandwich complexes of titanium bearing eta1 or eta2 bound nitroxide ligands are highly active catalysts for the polymerisation of propylene to high molecular weight atactic poly(propylene).
photochromic ligand that binds in one configuration but dissociates in the other form. We present mathematical proof that the maximum efficiency in property switching by such a photodissociableligand (PDL) is only dependent on the ratio of the association constants of both configurations. Rationaldesign by using DFT calculations was applied to develop a photoswitchable ligand with a high switching efficiency
An Incremental System To Predict the Effect of Different London Dispersion Donors in All‐
<i>meta</i>
‐Substituted Azobenzenes
作者:Chiara Di Berardino、Marcel A. Strauss、Dominic Schatz、Hermann A. Wegner
DOI:10.1002/chem.202104284
日期:2022.2.24
An incremental system for London dispersion has been developed that allows an easy back-of-the-envelope estimation when systematically altering the London dispersion donors. A simple equation is proposed that nicely reproduces the experimental results within error.