Spent the weekend on the coast in scorching temperatures, so posting the latest Alchemist link a little late – The Alchemist Newsletter: July 27, 2011 – New understanding of high-temperature superconductors meshes theory and experiment after twenty years of research and could lead to new developments, even a temperature rise, The Alchemist learns. In energy news, farmyard ordure is on the agenda, while in medicine magnetic nanoparticles could blast tumor cells with heat. A serendipitous discovery in organometallic chemistry could lead to color-change detectors for toxic gases while an open source solution to molecular database management is revealed for the smaller laboratory. Finally, female recognition from the ACSM after 56 years.
Fluorine in organic chemistry is an important topic across the synthetic pharmaceutical, agrochemical and materials areas because switching out hydrogen atoms selectivity for this element allows chemists to tune the reactivity of specific groups within a given molecule.
Now, chemists in Switzerland have turned to fluorine to help them make specific carbon-carbon bonds. The formation of C-C bonds is one of the most important steps in organic chemistry for the construction of complex molecules from simpler sub-units. Perhaps most important among the tools for building C-C bonds is the Friedel-Crafts reaction. It involves an attack on a carbocation-type substrate generated by a Lewis acid by the electron-rich pi-clouds of aromatic rings leading to an alkylated or acylated version of the aromatic ring.
A complete field within organometallic chemistry has emerged to support the Friedel-Crafts C-C endeavor. However, the instability of the phenyl ion means that coupling aromatic group to aromatic group using this chemistry has until now required a range of metal-mediated approaches. Jay Siegel and his colleagues at the University of Zürich hoped to simplify the schemes and avoid the need to use often expensive metal catalysts.
They have used Lewis acid activation of aryl fluorides to make biaryls intramolecularly. The Lewis acids are silicon cations generated by catalytic super acid, he told Chemistry Views. In a synthetic methods paper published in Science, Siegel and colleagues build on research published in Angewandte Chemie in which they revealed the C-F activation and work also published in Angewandte and JACS on the structure and properties of the silicon cations.
Siegel explains that this is a, “physical-organic success story of looking at a fundamental reactive intermediate and ending up with a new synthetic methodology.” He adds that, “Given that people put CF bonds into molecules to make them more inert, it is special that our method targets exactly these sites.”
Allemann, O., Duttwyler, S., Romanato, P., Baldridge, K., & Siegel, J. (2011). Proton-Catalyzed, Silane-Fueled Friedel-Crafts Coupling of Fluoroarenes Science, 332 (6029), 574-577 DOI: 10.1126/science.1202432
- The ‘molecular octopus’: A little brother of ‘Schroedinger’s cat’ – For the first time, the quantum behaviour of molecules consisting of more than 400 atoms was demonstrated by quantum physicists based at the University of Vienna in collaboration with chemists from Basel and Delaware.
- Neutral atoms made to act like electrically charged particles – Completing the story they started by creating synthetic magnetic fields, scientists from the Joint Quantum Institute (JQI), a collaboration of the National Institute of Standards and Technology (NIST) and the University of Maryland, have now made atoms act as if they were charged particles accelerated by electric fields.
- Imaging the paintings under the paintings of the Old Masters – Speaking at the 241st National meeting & Exposition of the American Chemical Society, an international team of scientists have now described use of a new technique to see the paintings under the paintings of Rembrandt, Caravaggio, Rubens, and other 17th Century Old Master painters.
- Amino acid synthesis hints at how the genetic code expanded – The detailed pathway for the biosynthesis of pyrrolysine – the 22nd and latest amino acid to be discovered – has been outlined by US researchers. The results show that each pyrrolysine is made from two lysine precursors, pointing towards a route by which new amino acids could have been introduced into the genetic code during evolution.
- Nanoparticles help reveal hidden fingerprints – Criminal investigations may benefit from new forensic methods based on nanoparticles. A technique using gold nanoparticles in combination with antibodies has shown promising results for enhancing fingerprints that are over a week old.
- A New Twist on Aqua Regia – By coupling common organic reagents with the inorganic reagent thionyl chloride (SOCl2), a team of Georgia Tech materials chemists has created an organic version of aqua regia, the centuries-old 1:3 mixture of concentrated nitric and hydrochloric acids that is one of the few substances known to dissolve noble metals such as gold.
Chemist and writer Robert Slinn picks six of the best for his regular web column on Reactive Reports – Slinn Pickings.
- Opalinus Clay as a potential host rock for nuclear waste repositories – Scientists at Johannes Gutenberg University Mainz (JGU, Germany) have studied natural claystone in the laboratory for more than four years in order to determine how the radioactive elements plutonium and neptunium react with this rock.
- Chemist discovers shortcut for processing drugs – A prolific University of Missouri chemist has discovered a quicker and easier method for pharmaceutical companies to make certain drugs.
- Sunlight can influence the breakdown of medicines in the body – A study from the Swedish medical university Karolinska Institutet has shown that the body's ability to break down medicines may be closely related to exposure to sunlight, and thus may vary with the seasons. The findings offer a completely new model to explain individual differences in the effects of drugs, and how the surroundings can influence the body's ability to deal with toxins.
- Synthetic biology: TUM researchers develop novel kind of fluorescent protein – Since the 1990s a green fluorescent protein known as GFP has been used in research labs worldwide. Protein designers at Technische Universitaet Muenchen have now taken it a step further: They have managed to incorporate a synthetic amino acid into the natural GFP and thus to create a new kind of chimeric fluorescent bio-molecule by means of synthetic biology. By exploiting a special physical effect, the fluorescent protein glows in turquoise and displays unmatched properties.
- New molecular robot can be programmed to follow instructions – Scientists have developed a programmable "molecular robot" — a sub-microscopic molecular machine made of synthetic DNA that moves between track locations separated by 6nm. The robot, a short strand of DNA, follows instructions programmed into a set of fuel molecules determining its destination, for example, to turn left or right at a junction in the track. The report, which represents a step toward futuristic nanomachines and nanofactories, appears in ACS's Nano Letters.
- Discovery of a biochemical basis for broccoli’s cancer-fighting ability – Scientists are reporting discovery of a potential biochemical basis for the apparent cancer-fighting ability of broccoli and its veggie cousins. They found for the first time that certain substances in the vegetables appear to target and block a defective gene associated with cancer. Their report, which could lead to new strategies for preventing and treating cancer, appears in ACS' Journal of Medicinal Chemistry.
- Dark-Colored Sodas May Have Toxic Backwash, Or Not – The Center for Science in the Public Interest (CSPI) has made a claim that “caramel coloring” used to improve the eye appeal of colas and other dark-colored soft drinks contains the carcinogenic by-products 2-methylimidazole and 4-methylimidazole (shown) and thus might be a cause of thousands of cancers in the U.S. The nonprofit consumer advocacy organization made its announcement via a regulatory petition filed with the Food & Drug Administration on Feb. 16.
- Measuring cells’ oxygen levels with PEBBLEs – Scientists in Germany have developed a strategy to visualise oxygen concentrations in cells to better understand its role in biological reactions such as metabolism.
- Chemical mystery of antifungal compound solved – US researchers have applied synthetic organic chemistry to crack a mystery that has baffled scientists for more than 50 years: how the powerful, naturally occurring antifungal compound amphotericin B interacts with sterols in cell membranes.<br />
The work, carried out by Martin Burke's group at the University of Illinois at Urbana-Champaign, could open the way to reducing amphotericin's toxic side effects, and to developing new drugs to replace faulty proteins in human cells – as a kind of molecular prosthesis.
- World’s ‘coolest’ physics study – The interior of a powerful machine newly installed at The University of Western Australia is not only the coldest place in the State, it is colder by far than anywhere in Antarctica or even in outer space.
The latest issue of “Slinn Pickings”. Chemistry news handpicked by chemist and writer Robert Slinn, who distils the chemical web in his regular guest blog posts for Reactive Reports.
- Sugarcane bioethanol: Environmental implications – An article in the current issue of Global Change Biology Bioenergy assessed the net greenhouse gas savings of bioethanol from sugarcane as compared to the use of fossil fuels.
- New growth inhibitors more effective in plants, less toxic to people – A Purdue University scientist and researchers in Japan have produced a new class of improved plant growth regulators that are expected to be less toxic to humans.
- Blood protein in lung cancer could improve diagnosis and treatment – Scientists are reporting discovery of a protein in the blood of lung cancer patients that could be used in a test for the disease — difficult to diagnose in its earliest and most treatable stages — and to develop drugs that stop lung cancer from spreading. Their study appears in ACS's Journal of Proteome Research.
- Hair dyeing poised for first major transformation in 150 years – Technological progress may be fast-paced in many fields, but one mundane area has been almost left in the doldrums for the last 150 years: The basic technology for permanently coloring hair. That's the conclusion of an analysis of almost 500 articles and patents on the chemistry of permanent hair dyeing, which foresees much more innovation in the years ahead, including longer lasting, more-natural-looking dyes and gene therapy to reverse the gray. The article appears in ACS's journal Chemical Reviews.
- Does fluoride really fight cavities by ‘the skin of the teeth’? – In a study that the authors describe as lending credence to the idiom, "by the skin of your teeth," scientists are reporting that the protective shield fluoride forms on teeth is up to 100 times thinner than previously believed. It raises questions about how this renowned cavity-fighter really works and could lead to better ways of protecting teeth from decay, the scientists suggest. Their study appears in ACS's journal Langmuir.
- Combined molecular study techniques reveal more about DNA proteins – Illinois researchers have combined two molecular imaging technologies to create an instrument with incredible sensitivity that provides new, detailed insight into dynamic molecular processes. Two physics professors combined their expertise in single-molecule biophysics — fluorescence microscopy and optical traps — to create a unique instrument that measures both a DNA-regulating protein's motion and conformational changes as it acts.
- Penn Physicists Develop Scalable Method for Making Graphene – New research from the University of Pennsylvania demonstrates a more consistent and cost-effective method for making graphene, the atomic-scale material that has promising applications in a variety of fields, and was the subject of the 2010 Nobel Prize in Physics.
- Protein identified that serves as a switch in a key pathway of programmed cell death – Work led by St. Jude Children's Research Hospital investigators provides fresh insight into mechanisms controlling programmed cell death pathways and offers new targets in the fight against cancer and virus-infected cells. Work led by St. Jude Children's Research Hospital scientists identified how cells flip a switch between cell survival and cell death that involves a protein called FLIP.
- Earth’s missing xenon could be hiding in quartz – What's happened to the Earth's missing xenon? For decades scientists have known that the abundance of xenon is curiously lower than predicted from comparisons with the other noble gases. Yet they have been unable to determine why. Now chemists in Canada have evidence that it is residing in the ground beneath our feet.
- Unravelling chromosomes – Danish scientists have used a micro device to isolate centimetre-long portions of human DNA to help study the genetic make-up of diseased cells. Rodolphe Marie at the Technical University of Denmark, Kongens Lyngby, and colleagues made the device to isolate chromosomes from cell extract samples and manipulate them in such a way that the strands remain intact.
Robert Slinn scours the web for the latest chemistry news for Reactive Reports.
- Researchers Discover New Way to Design Metal Nanoparticle Catalysts – Researchers at Northwestern University have discovered a new strategy for fabricating metal nanoparticles in catalysts that promises to enhance the selectivity and yield for a wide range of structure-sensitive catalytic reactions.
- Simpler way of making proteins could lead to new nanomedicine agents – Researchers have developed a simple method of making short protein chains with spiral structures that can also dissolve in water, two desirable traits not often found together. The researchers observed that as they increased the length of the side chains with charges on the end, the polypeptides' propensity for forming helices also increased. Such structures could have applications as building blocks for self-assembling nanostructures and as agents for drug and gene delivery.
- Needle-in-a-haystack search identifies potential brain disease drug – Scientists who examined more than 10,000 chemical compounds during the last year in search of potential new drugs for a group of untreatable brain diseases, are reporting that one substance shows unusual promise. The early positive signs for so-called prion diseases come from research in laboratory mice and cell cultures, they say in a report in ACS' Journal of Medicinal Chemistry.
- Bacteria living on old-growth trees ?may help forests grow – By collecting mosses on the forest floor and then at 15 and 30 meters up into the forest canopy, Dr. Lindo was able to show both that the cyanobacteria are more abundant in mosses high above the ground, and that they "fix" twice as much nitrogen as those associated with mosses on the forest floor.
- New high-performance lithium-ion battery ‘top candidate’ for electric cars – Scientists are reporting development of an advanced lithium-ion battery that is ideal for powering the electric vehicles now making their way into dealer showrooms. The new battery can store large amounts of energy in a small space and has a high rate capacity, meaning it can provide current even in extreme temperatures.
- Sifting Through Complex 2-D NMR Data – To understand how an organism's biochemistry relates to biological functions, such as reproduction or cell-to-cell communication, researchers struggle to make sense of complex chemical mixtures of metabolites. Now a study demonstrates a technique to analyze two-dimensional nuclear magnetic resonance data.
- Power of Research: a new online game to inspire the scientists of the future – A new strategy browser game – the "Power of research" – is officially launched today. Supported by the European Commission, "Power of Research" has been developed to inspire young Europeans to pursue scientific careers and disseminate interesting up-to-date scientific information.
- Researchers achieve a full film frame of a family of proteins essential for cell function – Researchers at IRB Barcelona have completed the 3D structural sequence adopted by several essential proteins in the exchange of substances between the extra and intracellular milieu. This finding provides a global perspective of the structural changes that occur in these relevant proteins during basic cell processes, such as protein synthesis, the regulation of metabolism and cell volume, and nerve transmission.
- Polymer coat helps nanoparticles penetrate mucus – US researchers have shown how biodegradable, medically safe polymer coatings can help nanoparticles penetrate the mucus lining that protects human tissues to deliver drugs efficiently.
- Capsules for safer and more reliable lithium ion batteries – Capsules coated onto electrodes could mitigate potential problems with lithium ion batteries by turning the batteries off when they overheat and 'healing' the electrodes when they crack and degrade, according to a researcher in the US. Scott White from the University of Illinois at Urbana-Champaign says that in his lab self-healing materials have inspired a new concept for battery safety and self-repair.
More chemistry news from chemist Robert Slinn for Reactive Reports in his regular column: Slinn Pickings.