Asymmetry of molecules can make the difference between a drug and a poison. It is therefore vital to control this parameter in synthesis. Polish researchers found how stirring a reaction mixture in the presence of suitable seeding crystals can strongly affect the products. They report their findings in the European Journal of Inorganic Chemistry.
Witold Rybak and co-workers at the University of Wroc³aw investigated the synthesis of a platinum(IV) polysulfide anionic complex (NH4)2[Pt(S5)3]•2H2O and observed that vigorous stirring during the preparation played a unique role in determining the properties of the product obtained. Without stirring, the product was racemic, its composition did not depend upon the reactants or on the crystals used for seeding.
When the reaction mixture was stirred vigorously during the whole synthesis in the presence of a particular seeding crystal, however, the properties of the product were surprisingly similar to those of the seeding crystal used. This observation and the accompanying study also led to the elucidation of the mechanism of this chiral synthesis.
Previously, the asymmetric transformation of the reaction product during crystallization was believed to determine the properties of the final product obtained; however, this assumption had not been able to explain some experimental observations. A closer study has now led to the recognition of the true mechanism: the reason behind the formation of a product of a certain configuration is a crystallization-induced autocatalytic asymmetric synthesis mechanism. The seeding crystal molecule catalyzes the formation of more molecules of its own kind.
This discovery can be used to synthesize products of the desired chirality by selecting the seeding crystal with the right configuration and performing the synthesis under continuous stirring.Author: Witold Rybak, Uniwersytet Wroc³awski (Poland), http://faculty.pages.wchuwr.pl/pracownik/WitoldRybak/en
European Journal of Inorganic Chemistry , 2012, No. 23, Permalink to the article: http://dx.doi.org/10.1002/ejic.201200479
Witold Rybak | Wiley-VCH
Symbiotic bacteria: from hitchhiker to beetle bodyguard
28.04.2017 | Johannes Gutenberg-Universität Mainz
Nose2Brain – Better Therapy for Multiple Sclerosis
28.04.2017 | Fraunhofer-Institut für Grenzflächen- und Bioverfahrenstechnik IGB
More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.
Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...
Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.
"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...
The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.
Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...
The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...
Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.
Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...
28.04.2017 | Event News
20.04.2017 | Event News
18.04.2017 | Event News
28.04.2017 | Medical Engineering
28.04.2017 | Earth Sciences
28.04.2017 | Life Sciences