ChemWeb Newsletter

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This week The Alchemist learns of an award to an entire nation for its efforts in energy research and development. In research news we hear of a record-breakingly short metal-metal bond that beats the textbook great, counterintuitive results of electron pairing comes to light in bismuth, and how to extract the organic from water for a fresher taste using older sand filters instead of new. Also in this week's issue, a biotech solution to sweetness and a heads up for a Mickey Mouse protein involved in channeling potassium ions.




A double award for Canada at the twentieth annual World Energy Congress in Rome, Italy, sees the nation commended for its leadership in hydrogen and fuel cell technologies with an award to British Columbia's Hydrogen Highway program winning the Technical Achievement Award. The International Partnership for the Hydrogen Economy (IPHE) has also elected Canada as its new chair. "The Government of Canada is proud to be recognized on the world stage for our work on the BC Hydrogen Highway," said Deputy Minister of Natural Resources Canada Gary Lunn. "Canada is doing what it takes to be a world leader in the fight against climate change and in the development of clean energy. The development of Hydrogen fuel cell technologies is part of our balanced plan aimed at reducing emissions of greenhouse gases and air pollutants and encouraging our economic growth."





A dichromium coordination compound with the shortest new Cr-Cr distance seen in almost three decades has been synthesized by chemists at the University of Delaware. The new shortest distance record, a mere 1.803 A?ngstroms, set by Klaus Theopold and his colleagues beats Albert Cotton's 1978 record for a dichromium compound. Theopold and Kevin Kreisel had been researching the chemistry of chromium for several years, the metal is an important industrial catalyst for making plastics such as polyethylene, when they serendipitously hit on the new compound. They confirmed its structure and bond lengths using X-ray crystallography. "This molecule is probably not practically useful. We're not going to get a patent here or cure cancer," Theopold says, "Records define the range in which things can exist. It's just an interesting molecule from a fundamental scientific standpoint."





The same pairs of electrons that give rise to superconductivity in the BCS model of those materials can also form in their opposite number - electrical insulators. The finding is entirely counterintuitive, according to Brown University's James Valles. "Cooper pairing is not only responsible for conducting electricity with zero resistance," he explains, "but it can also be responsible for blocking the flow of electricity altogether." The BCS theory, named for John Bardeen, Leon Cooper and Robert Schrieffer, (Cooper is currently at Brown), says that superconducting electrons form pairs that correlate their motion with other electron pairs to flow smoothly and infinitely. Stewart has now observed the same Cooper pairs in bismuth, which is a superconductor in a thick layer but in very thin layer just tens of nanometers thick it is a strong insulator. The findings could help researchers understand the limits of superconductivity and, perhaps, push them to create insulated wires that conduct electricity without heating up. Cooper said the work sheds important and intriguing new light on quantum effects.





Two organic molecules that give fresh water an earthy taint are perfectly harmless but undesirable to many people. Now, Australian scientists have discovered that old sand filters with an active biological film are much more effective at breaking down these molecules, geosmin and methylisoborneol (MIB), than new filters with no biofilm. According to Gayle Newcombe, Research Leader at the Applied Chemistry Unit of the Australian Water Quality Centre in Salisbury, South Australia, "Although adverse odors do not present a risk to human health, their presence often leads to a misconception that the water is unsafe for drinking." Geosmin is also familiar to many people as the earthy smell of rain it is itself a bacterial natural product.





Food manufacturers are ever on the look out for new sweet-tasting compounds that are easy to produce or extract, have the same effect on the palate as sugar but with close to zero food calories. Now, a new sweetener, based on a protein extract from a West African fruit, could provide all the sweetness and "lite". Indeed, researchers at the University of Wisconsin have spent the last few years investigating the structure-activity relationships in sweet proteins. They have also devised a production method that should allow scale-up of this extract, brazzein, for the low-calorie drinks and food industries. Brazzein is 2000 times sweeter than sucrose when compared to a 2% sucrose solution in water, has none of the bitter after taste of other artificial sweeteners and is heat stable.





A detailed structure of a potassium ion channel protein has been obtained revealed by a Nobel team in the US. The structure shows the channel in a relatively natural state and reveals how lipid molecules within the cell membrane influence channel function. They do so through their interaction with the voltage-sensing Mickey Mouse ears that protrude into the lipid layer. Membrane-bound proteins are among the most fascinating molecules in biology but are notoriously difficult to crystallize and study in detail in their natural, or even near-natural state. Now, Roderick MacKinnon and colleagues at HHMI have developed a new technique, lipid-detergent-mediated crystallization, which could open the door to studying the hundreds of membrane proteins previously inaccessible in their natural environment to crystallography.