ChemWeb Newsletter

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overview

This week, The Alchemist takes a look at ionic liquid drugs, puzzles over the possibility of anti-magnets, discovers that gamma radiation could improve artificial joints, and spots a stretched carbon-carbon bond. In theoretical chemistry, we hear how mathematics is improving modeling, a long-serving science writer receives a major award from the American Chemical Society.




Ionic liquids have commonly been touted as safer, more environmentally benign alternatives to toxic and flammable volatile organic solvents. They are usually made from bulky cation and anion pairs the energy of crystallization of which precludes them from forming a solid at room temperature so they remain liquid. Australian chemists have now demonstrated that by choosing a pharmaceutically active ion as one of the pair and a biocompatible base as the other component it is possible to make a liquid form of drug that is more stable and more soluble than the parent compound. Such ionic liquid drugs could be used in rapid transdermal delivery. They also side-step a significant problem of many solid, crystalline drugs in that being liquid and so amorphous there are no issues of active drugs degrading to less active polymorphic forms.





Scientists have experimented with magnetism for centuries, but one aspect that has remained elusive is a way to shield, or cloak, a magnet. Spanish researchers have now come up with a scheme based on a hybrid meta-material containing a superconducting component that could "switch off" the field of a permanent magnet without actually modifying the field. The meta-material prevents an external magnet from affect an object hidden within and also prevents any magnetic fields within from leaking out, rendering a magnet undetectable. The research is analogous to the recent develop of meta-materials that can render objects "invisible" to microwaves and putatively visible light. The team suggests that antimagnets might have applications in improving magnetic resonance imaging or in creating "stealth" ships or aircraft.





Gamma radiation can improve the biocompatibility and wear resistance of artificial, or prosthetic, joints according to researchers in China. Maoquan Xue of the Changzhou Institute of Light Industry Technology, has investigated the effect of adding ceramic particles and fibers to two experimental materials for coating prosthetic joints, UHMWPE (ultra-high-molecular-weight polyethylene) and PEEK (polyether ether ketone). He has demonstrated that radiation treatment of these composites leads to much more robust materials for prosthetic joints.





Research undertaken at two universities in Europe and the SLAC National Accelerator Laboratory at Stanford reveals that attractive forces between different parts of a single molecule can boost the stability of very long carbon-carbon bonds. The researchers joined pairs of diamondoids together to make three new alkanes with ultra-long central C-C bonds. It was the presence of the bulky diamondoid groups that forced these C-C bonds to be stretched far beyond their normal lengths from about q5 nanometers to the longest C-C bond ever recorded in an alkane at 17 nm. The molecules are surprisingly stable because attractive forces on opposite sides pull the molecule tight.





A new, improved approach to the mathematics of molecular dynamics simulations sees atomistic data being put back in the frame. A team at the University of Oregon has devised an analytic approach that takes into account often-neglected thermodynamic and molecular parameters to produce much richer simulations than were previously possible. They examined simulations in which thousands of macromolecules of polyethylene were represented as interacting soft particles, coarse-grained modeling in other words and successfully applied their new approach to bring the missing fine-grained information back into the simulations to make them more realistic.





Veteran science writer Paul Raeburn is the 2012 recipient of the James T. Grady-James H. Stack Award for Interpreting Chemistry to the Public. Raeburn currently is a media critic at the Knight Science Journalism Tracker and is well known for his many years of reporting on science for the Associated Press during 1981 to 1996. Raeburn is developing a new graduate program in science, medical and environmental journalism at Florida Atlantic University. He will receive the Grady-Stack award at the ACS' 243rd National Meeting & Exhibition in San Diego in March 2012.