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
At last, butterflies get a bigger, better evolutionary tree
16.02.2018 | Florida Museum of Natural History
New treatment strategies for chronic kidney disease from the animal kingdom
16.02.2018 | Veterinärmedizinische Universität Wien
Breakthrough provides a new concept of the design of molecular motors, sensors and electricity generators at nanoscale
Researchers from the Institute of Organic Chemistry and Biochemistry of the CAS (IOCB Prague), Institute of Physics of the CAS (IP CAS) and Palacký University...
For photographers and scientists, lenses are lifesavers. They reflect and refract light, making possible the imaging systems that drive discovery through the microscope and preserve history through cameras.
But today's glass-based lenses are bulky and resist miniaturization. Next-generation technologies, such as ultrathin cameras or tiny microscopes, require...
Scientists from the University of Zurich have succeeded for the first time in tracking individual stem cells and their neuronal progeny over months within the intact adult brain. This study sheds light on how new neurons are produced throughout life.
The generation of new nerve cells was once thought to taper off at the end of embryonic development. However, recent research has shown that the adult brain...
Theoretical physicists propose to use negative interference to control heat flow in quantum devices. Study published in Physical Review Letters
Quantum computer parts are sensitive and need to be cooled to very low temperatures. Their tiny size makes them particularly susceptible to a temperature...
Let’s say the armrest is broken in your vintage car. As things stand, you would need a lot of luck and persistence to find the right spare part. But in the world of Industrie 4.0 and production with batch sizes of one, you can simply scan the armrest and print it out. This is made possible by the first ever 3D scanner capable of working autonomously and in real time. The autonomous scanning system will be on display at the Hannover Messe Preview on February 6 and at the Hannover Messe proper from April 23 to 27, 2018 (Hall 6, Booth A30).
Part of the charm of vintage cars is that they stopped making them long ago, so it is special when you do see one out on the roads. If something breaks or...
15.02.2018 | Event News
13.02.2018 | Event News
12.02.2018 | Event News
16.02.2018 | Information Technology
16.02.2018 | Health and Medicine
16.02.2018 | Physics and Astronomy