An international team of chemists has discovered a new piece to the puzzle of how a powerful base used in organic synthesis, cesium carbonate, plays a pivotal role during a catalytic reaction.
The research, published by the Journal of the American Chemical Society, was led by Jamal Musaev, a theoretical chemist at Emory University, and Ken Itami, an experimental chemist from Nagoya University in Japan. Sun Yat-Sen University in Guangzhou, China, also contributed to the findings.
Many organic chemistry reactions are acid/base reactions, involving the exchange of positively charged hydrogen atoms. Acids donate the positively charged hydrogen and bases accept it.
The current research focused on the use of cesium carbonate as a base. Cesium carbonate has recently been observed to accelerate a particular class of catalytic reactions, a phenomenon termed the "cesium effect."
The use of cesium carbonate base and carboxylic acids co-catalysts have been shown to be critical in a number of recent carbon-hydrogen (C-H) bond functionalization reactions.
The full story behind the impact of this base was previously not clear. It was known that the cesium base removed hydrogen protons, or scavenged acidic acid, from the solution, and was also involved in the exchange of ligands during a reaction, but these two factors did not explain the acceleration seen.
This recent work offers a new explanation. The researchers found that cesium base can generate an aggregate state: The molecules come together creating a cluster that is actually the starting point for the catalytic reaction, and not the discreet carboxylic acids and carbonate complexes as was previously thought.
"One-by-one, we are identifying key components of catalytic reactions and then putting them all together," Musaev says. "It's difficult work, but important, because the more your understand the reaction the better you can predict ways to modify it and control it."
The findings about how the base acts in these reactions has the potential to impact the development of not just new C-H functionalization reactions, but the way that catalytic reactions in general are considered.
The collaboration of chemists from across three continents is a result of the Center for Selective C-H Functionalization (CCHF), an NSF National Center for Chemical Innovation headquartered at Emory.
C-H functionalization holds the potential to make organic synthesis faster, simpler and greener, and could open up new ways to develop drugs and other fine-chemical products.
The CCHF encompasses 15 top research universities from across the United States, and recently expanded to include institutes in Asia and Europe. The global network forged by the CCHF brings together leading players from around the world, representing the range of specialties that will be required to make the critical breakthroughs needed to bring C-H functionalization into the mainstream of chemical synthesis.
Megan McRainey | Eurek Alert!
Could this protein protect people against coronary artery disease?
17.11.2017 | University of North Carolina Health Care
Microbial resident enables beetles to feed on a leafy diet
17.11.2017 | Max-Planck-Institut für chemische Ökologie
The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.
Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...
Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.
That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...
Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.
During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....
The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.
Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...
Pillared graphene would transfer heat better if the theoretical material had a few asymmetric junctions that caused wrinkles, according to Rice University...
15.11.2017 | Event News
15.11.2017 | Event News
30.10.2017 | Event News
17.11.2017 | Physics and Astronomy
17.11.2017 | Health and Medicine
17.11.2017 | Studies and Analyses