ChemWeb Newsletter

Not a subscriber? Join now.December 6, 2005


The Alchemist this week turns on to molecular switches, neutron news, antimatter molecules, and cannabis inhalers. Finally, we also get turned on to super compressible nanotube foams.

Researchers at Pennsylvania State, Rice, and Oregon Universities have devised a method for switching the state of single molecules. The research demonstrates that single-molecule switches can made to respond predictably in an electric field. The researchers engineered different molecules to switch on and others to switch off in response to the same electric field. Paul Weiss and colleagues will publish details of their work in JACS in December. The next step is for chemists to find a way to wire these molecular switches together.

November 24, the Max Planck Institute for Metals Research in Stuttgart and the Technical University of Munich inaugurated a new kind of neutron/X-ray reflectometer called "N-REX +" which the developers say will provide new insights into materials such as high temperature superconductors, semiconductors, and ceramics. High flux neutrons could be key to understanding the behaviour of materials and thin films at the atomic level.

"Molecules" composed of matter and its opposite number antimatter have been observed in a fleetingly short-lived gas. The molecules form as a result of interactions between positronium atoms - a bound electron and positron - in a dense but short-lived gas of such atoms. Allen Mills of the University of California at Riverside and his colleagues collected and compressed positrons in a magnetic trap and then fired super-intense positron pulses at a thin film of "nano-porous" silica. The team observed a much higher positronium decay rate than expected, suggesting that some of the atoms were joining up to form "molecules".

UK multiple sclerosis sufferers, and potentially those with rheumatoid arthritis, could soon be puffing on "cannabis" inhalers thanks to a government ruling. The British Home Office will allow the mouth spray drug, Sativex, to be imported for individual patients in exceptional cases, provided it is physician recommended. It is unclear how many of the estimated 85,000 MS patients in the UK might benefit from Sativex. Anecdotal evidence suggests, however, that some use more traditional forms of cannabis to relieve their symptoms.

Films of aligned carbon nanotubes are apparently super-compressible and could be used to create nanotube foams that maintain their resilience even after thousands of compression cycles. In conventional foams, strength and flexibility are mutually exclusive. With the carbon nanotube foam, there is no such tradeoff. These nanotubes can be squeezed to less than 15% of their normal lengths and might be useful in flexible electromechanical systems or energy-absorbent coatings.