Conjugated tetraenes are important key substructures in electronic materials, natural products and pharmaceutical molecules. However, they are difficult to synthesize. They are conventionally prepared by repetitions of the stoichiometric reactions using phosphorus reagents and subsequent reduction and partial oxidation. For making one C=C double bond, one needs to conduct 3 step reactions by this procedure. Each process produces wastes of phosphorus oxides and metal compounds such as lithium, aluminum and manganese. Removal of organic solvents and purification processes are also required. An alternative catalytic approach is the cross-coupling reaction catalyzed by a Pd complex but this method needs to prepare an activated alkenyl or dienyl metal species in advance.
TUAT researchers have achieved the new synthetic route of conjugated tetraenes from inexpensive and easily available 1,3-butadiene and substituted acetylenes by a one-pot approach under mild conditions. This is the most straightforward synthetic method ever reported. This new method has been published in the ACS journal, Organometallics.
“The Ru catalyst precisely distinguishes butadiene and substituted acetylene molecules and new carbon-carbon bonds are formed among a butadiene with two acetylenes just by migration of the terminal hydrogen atoms in butadiene. Interestingly, this catalysis proceeds regio- and stereoselectively and no wastes are produced from the reaction” said Masafumi Hirano, a TUAT professor of chemistry and principal of the study.
The current scope is, however, limited to internal alkynes (1,2-disubstituted acetylenes), and the present reaction entails internal side groups in the conjugated tetraenes. However, facile detachment of some side groups is possible to give the linear conjugated polyenes and this protocol will be disclosed in the 98th annual meeting of the Chemical Society of Japan.
Instead of 1,3-butadiene, 1-substituted 1,3-butadienes such as 1,3-pentadiene or 2,4-pentadienoate are also possible to use for the reaction but conjugated trienes are produced in this case.
The mechanism is revealed by the isotopic labeling experiments and the stoichiometric reactions by use the 1,3-butadiene complex of ruthenium. These studies demonstrate this reaction to be a formal syn addition of the terminal C-H bond in butadiene to acetyelene.
Conjugated tetraenes are important key substructures in organic-electronic materials, biologically active natural products such as vitamins, and anti-mycotic drugs and this new method may contribute to the preparations of them. “The ultimate goal is versatile synthesis of targeted conjugated polyene molecules and to supply conjugated polyene substructures by this inexpensive method”, said Masafumi. That could lead to facile and inexpensive synthesis of molecules for electronic materials and anti-mycotic drugs.
Masafumi and colleagues set out to prepare the targeted molecules containing conjugated tetraene substructures.
What do smart phones, electric vehicles and solar panels have in common? They all demand more and more battery power to keep our homes, jobs and vehicles running. Lithium ion is still the “gold standard,” but researchers are looking at the entire periodic table for new combinations of elements that can conduct and store electrons in smarter ways. And the sooner they find it, the sooner society can get off fossil fuels and use more sustainable energy sources. “With the combination of new materials, new design concepts, and new production and manufacturing methodologies, I believe we will get there,” said Esther Takeuchim, professor of advanced power systems at SUNY Buffalo, Here’s a look at five new battery techs – some ready for market in the next year, others just over the horizon.
Sendyne Corp., a developer of sensing, modeling/simulation, and control products, announces the immediate availability of CellMod, the first lithium-ion battery simulation tool that can predict cell and pack behavior with an accuracy of better than 5 percent under a wide range of test conditions. The software includes Sendyne’s Pseudo-2D compact physics-based Li-ion battery cell model coupled with Sendyne’s proprietary dtSolve™, a tool that executes several orders of magnitude faster than other commercially available numerical solvers. The software may be used as a standalone tool or can be integrated with other simulation packages for whole system co-simulation via the Functional Mockup Interface (FMI), an open standard supported by all major simulation platforms.
Photosynthesis: fundamental mechanism for life on this planet, scourge of GCSE biology students, and now a potential way to fight climate change. Scientists are working hard to develop an artificial method that mimics how plants use sunlight to transform CO2 and water into something we can use as fuel. If it works, it’ll be a win-win scenario for us: not only will we benefit from renewable energy produced in this manner, but it could also become an important way to reduce CO2 levels in the atmosphere.
Seventy two (72) more mineral blocks are set to go under the hammer before the end of this financial year.
London-based brokerage SP Angel has outlined the key trends that characterised the basket of energy metals during 2017 and the the outlook for 2018 in its new ‘Battery Raw Material Review, Outlook – SP Angel Commodity Research Book’ published on Wednesday.