ChemWeb Newsletter

Not a subscriber? Join now.December 29, 2010

contents
what's new on ChemWeb

The Events Calendar at ChemWeb.com lists conferences, seminars, trade shows, user group meetings, webinars and many other events of interest to ChemWeb members. The listings are free and they come from you - our members. We invite ChemWeb members to submit events to share with the ChemWeb community. Visit www.chemweb.com and click on *events* in the top navigation bar. To submit an event to the calendar, you should first login to the site and look for the *add item* link on the events page.



overview

This week The Alchemist learns, it seems, that IUPAC has been meddling with alchemical matters and changing the atomic weights of ten chemical elements while carbon allotrope graphene gets turned on and tuned in to radio. In the natural world new insights into how terpenes are biosynthesized could open up a whole new approach to organic synthesis of natural product like molecules. Mimicking mussels looks like a good way to stick DNA to any surface for biotech applications, as it were, while metal methane could be the next step in the evolution of the chemical industry away from oil-based feedstocks. Finally, the US government is sending out strict memos to scientists ordering greater transparency and scientific integrity; heads of departments are on a deadline to set their compliance programs in motion.




The atomic weights of a clutch of chemical elements are to be revised under an IUPAC directive. Since it was first introduced in 1869, the periodic table of the chemical elements has been added to on many occasions. But, the latest changes will see the atomic weight values for a ten elements being replaced with a range of values to better accommodate their isotopic distribution. The elements that will be affected are: hydrogen, lithium, boron, carbon, nitrogen, oxygen, silicon, sulfur, chlorine and thallium. Elements with only a single isotope or with very rare isotopes, such as fluorine and gold, will retain their fixed weights.





Graphene has not been out of the news since its discovery and especially since it became a physics Nobel chemical. Now, a nanoscopic trampoline comprising a single graphene sheet suspended between two electrodes has been shown to pick up radio signals. The device might be useful in the next generation of radio devices. Researchers have been hoping to exploit nanoelectromechanical resonators to filter and generate radio signals directly for some time. The new graphene device side-steps the problem of parasitic capacitance seen with other resonators and so ensures the signals are not drowned out at radio frequencies. Graphene can resonate at Gigahertz frequencies, which is the part of the spectrum of most interest to mobile phone manufacturers and those making other radio-frequency communications devices.





The first X-ray crystal structure of taxadiene synthase, an enzyme key to terpene and terpenoid biosynthesis in many living organisms, confirms a theoretically predicted link between two enzyme classes in the evolution of potentially hundreds if not thousands of diverse compounds, including the natural product anticancer drug Taxol, and many chemicals that give flowers and foods their color, taste, and odor. The X-ray work reveals that the enzyme taxadiene synthase has a class I domain similar to that seen in another enzyme, pentalenene synthase and other class II regions that resemble those seen in the enzyme squalene-hopene cyclase. The research not only improves our understanding of terpene and terpenoid evolution but could be exploited in engineered microbes to make synthetic terpenes for medicine and agriculture.





Mussels can stick well to almost any surface whether wave-lashed rock, the metal supports of a pier or the wooden hull of a fishing boat. Now, this well-remarked adhesive ability has been mimicked in the laboratory with a catecholamine polymer allowing US researchers to attach DNA firmly to a substrate for microarray applications that side-step costly adhesion techniques that can only be used with one substrate. The new technology allows DNA and other biomolecules to be attached firmly to almost any surface, lending mussel muscle to biotech and biomedical research. The adhesive can be used for glass substrates, as well as less common substrates such as gold, platinum, oxides, semiconductors, or other polymers, without interfering with the activity of the biomolecules being anchored.





Chemists have finally succeeded in adding a metal atom to a methane gas molecule, so creating a class of organometallic compound that could reinvigorate the chemical industry, especially in the area of organic synthesis. Researchers at The University of Arizona have also determined the precise structure of their metal-methane hybrid molecule, made with zinc, and confirm theoretical calculations that suggested such a species might be feasible. The so-called metal-methane insertion required to make this hybrid is not a complicated chemical reaction but nor is it something that is likely to happen in nature. "There is a big push in the chemical industry and in chemistry in general, to make use of fairly common organic compounds such as methane and turn them into something that can serve as a source for a product," explains team leader Lucy Ziurys. This milestone could be the big push the industry needs to move forward.





The White House has issued a memo to all heads of departments and agencies to help enforce President Obama's March 9, 2009 didact on scientific integrity. This latest memo from John P. Holdren provides further guidance to Executive Branch leaders as they implement Administration policies on scientific integrity. The new memorandum describes the minimum standards expected as departments and agencies craft scientific integrity rules appropriate for their particular missions and cultures, including a clear prohibition on political interference in scientific processes and expanded assurances of transparency. Responsible heads have now got about 4 months to respond on their progress in fullfiling these rules.