ChemWeb Newsletter

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Absolute configurations reveal themselves through NMR using Residual Dipolar Couplings in small molecules, according to an international team who have put it to work on an anticancer compound, while a failed antidepressant could be marketed as a novel treatment for female sexual dysfunction. In the world of inorganic materials, researchers have discovered a new class of composites in which dihydrogen layers trap atoms of the noble gas xenon to form a stable solid under extreme pressures. A new approach to carbon nanotubes provides chemists with an insider view of these unique materials, while an award for $2.8 million looks set to lead the way to truly room temperature superconductors. Finally, controversial claims about the state of the environment suggest that total economic collapse or the building of a nuclear power station a day is the only way rising carbon emissions will be stymied.




A new approach to NMR spectroscopy allows chemists to obtain more information than is usually possible about the structure of their compounds. Roberto Gil of Carnegie Mellon University in Pittsburgh and colleagues have used Residual Dipolar Couplings in the small molecule jaborosalactol 24, a potential anticancer drug, to work out its three-dimensional structure, something that would otherwise be possible only with diffraction techniques. They verified the structure with X-ray powder diffraction data. The NMR technique will be useful for compounds for which X-ray data are unavailable as well as offering a quicker and simpler structure determination.





A failed antidepressant turns out to have a side-effect that could improve the sex lives of women with low libido. A reduction in sex drive affects between one in ten and one in four women depending on age and whether they have been through the menopause. German pharmaceutical company Boehringer Ingelheim claims that its drug, flibanserin, "boosted" satisfying sexual activity in female participants in a trial of the antidepressant. A daily 100 milligram dose apparently increased satisfying sexual events per month from about 3 to between 4 and 5, on average. Placebo also increased such events to almost 4 per month, on average. Such figures do not fill all observers with confidence, especially those who see the medicalization of normal life as a serious problem of the modern industry.





A new approach to storing large volumes of hydrogen gas has been discovered, which might take us one step closer to a so-called hydrogen economy. When compressed at high pressure with the relatively unreactive noble gas xenon, molecular hydrogen forms a previously unknown solid, according to Maddury Somayazulu of the Carnegie Institution's Geophysical Laboratory. The novel material forms at 41000 atmospheres in a diamond anvil device and is stable with xenon pair distances close to those seen in dense metallic xenon. Xenon is actually too heavy and expensive for practical applications, but the insights the team is gaining into the behaviour of hydrogen under such conditions may lead them to a less dense and cheaper alternative.





There are limitations to studying carbon nanotubes (CNTs) particular as it is very difficult to get an insider view. That could change thanks to work by Nadya Mason and colleagues at the University of Illinois at Urbana-Champaign and Norman Birge at Michigan State University. They have developed a technique to map out changes in conductance through a CNT quantum dot. Superconducting tunneling spectroscopy allows the team to see what is happening inside the CNT rather than merely at its contacts. The approach could open up studies into CNT transistors and possibly even quantum computing devices.





Rising levels of the greenhouse gas may not be stabilized unless the global economy collapses or until we are building one nuclear power station every day. Tim Garrett, associate professor of atmospheric sciences at the University of Utah suggests that energy conservation will not be enough to ward off potentially catastrophic changes in the planet's climate caused by anthropogenic carbon emissions. "Stabilization of carbon dioxide emissions at current rates will require approximately 300 gigawatts of new non-carbon-dioxide-emitting power production capacity annually - approximately one new nuclear power plant (or equivalent) per day," Garrett says. "Physically, there are no other options without killing the economy."





A $2.8m grant to Professor Paul Ching-Wu Chu, founding director of the Texas Center for Superconductivity at the University of Houston, could lead to the development of truly high-temperature superconductors. Chu has everything to try for as no experimental or theoretical evidence exists to suggest that superconductivity at temperatures above room temperatures are not achievable. Superconductivity without the need for significant cooling could lead to near resistance-free electrical generation and transmission.