ChemWeb Newsletter

Not a subscriber? Join now.January 24, 2006


A nanocontainer and an elephant's tale catch is The Alchemist's all-seeing eye this week and appearing in the swirling mists - crystalline proteins, cannabinoids and bone, and walking water.

There is an obstacle to exploiting nanocontainers that might hold other molecules within - complex synthetic schemes. Now, Ralf Warmuth and colleagues at Rutgers University in New Jersey, USA, have produced an octahedral nanocontainer made up of eighteen distinct components that assembles itself in a single, elegant chemical reaction, removing the need for the usual long, complicated sequence of reactions. Their nanocontainer is big enough to trap small molecules and could be used as a novel catalyst, molecular sieve, or for pharmaceutical transportation.

Chemical analysis could help elephants and people live more harmoniously in countries such as Kenya where large free-roaming herds can wreak havoc on villages, livestock, and farmed crops. Researchers at the University of Utah analysed chemicals in elephant tail hair from those animals tagged with radio-GPS collars and so could track the diet and movements of the elephants across Kenya. Geochemist Thure Cerling and colleagues at the University of Utah determined the stable isotopes of carbon and nitrogen in African elephants' tail hair to help them correlate what the animals ate with where they ate it on the basis of GPS (Global Positioning System) data. Cerling says it is "important to quantify how much of elephants' diet comes from crops. It's going to help resolve elephant-human conflict by quantifying the crop damage done by elephants."

The bane of protein crystallographers is the common problem of proteins that simply will not crystallize; this is especially poignant when it comes to some of the more biomedically interesting of their number, such as the numerous membrane proteins, many of which do not succumb to even the most sophisticated crystallization techniques. Now, researchers at Imperial College London and the University of Surrey, both in the UK, have developed a new technique for crystallizing proteins, which could open up a whole range of materials to this powerful analytical technique. Naomi Chayen and colleagues have now successfully used porous BioGlass as novel nucleant to trap and encourage the growth of protein crystals. They found BioGlass induced the crystallisation of the largest number of proteins ever crystallised using a single nucleant, which could open up a whole new tranche of proteins to crystallographic studies.

A new approach to the debilitating bone loss disease osteoporosis could be on the horizon thanks to research by Andreas Zimmer and Meliha Karsak from the Bonn-based Life & Brain Center in Germany and collaborators in Israel, the UK, and the USA. The researchers have discovered a regulatory mechanism involved in bone loss linked to a chemical receptor in our bodies with a previously unknown function, which could lead to a new treatment. The team has now developed a new synthetic compound, HU-308, which activates CB2 and slows the development of osteoporosis in mice. This compound forms the basis for a cannabinoid-based, anti-osteoporotic type drug which has also been found to be free of any psychoactive side effects.

Droplets of water can "walk" uphill across a surface under their own steam according to Heiner Linke and his colleagues from the University of Oregon in Eugene. The self-propelled liquids could find use as a novel way to keep microprocessors cool and so allow them to run at higher speeds. To get droplets of water and other liquids to walk across a surface, the researchers etched a piece of brass with ratchet-like corrugations and then heated it to well above water's boiling point and exposed it to water. This produces a layer of water vapour, a Leiden frost layer, above the surface that allows a droplet of water to sit "on" the surface and to scoot across it with even the tiniest of applied forces.

Not a subscriber? Join now.January 10, 2006


This week, The Alchemist sniffs out a pong detector, looks at floppy space-age molecules, measures an enantiomeric success, and finds out how ongoing studies have revealed the longer-term benefits of the Alzheimer's drug Namenda. Finally, we go atmospheric to unearth the complex interactions of water and carbon dioxide.

Krishna Persaud and colleagues at the University of Manchester, UK, have developed a remote sensor for monitoring foul odors emerging from landfill and waste-water treatment sites. The new device makes manual sampling and human sniffers redundant by allowing real-time measurements of low concentration odorous gases to be detected. "Ultimately, this device has the potential to create a much healthier environment which will benefit both local communities and waste management companies by alerting them to the build up of bad odours and enabling them to ensure monitor methane emissions remain at a safe level," says Persaud.

US researchers hope to boldly go where no chemist has gone before, by taking the first step toward overcoming a decades-old challenge in chemistry - explaining reactions that occur within very cold clouds among the stars. Their findings could lead to new approaches to more down to earth chemistry. David Nesbitt and colleagues at JILA, a joint institute of the Commerce Department's National Institute of Standards and Technology (NIST) and University of Colorado at Boulder, and Joel Bowman at Emory University, Atlanta and Anne McCoy at The Ohio State University in Columbus, are investigating the super-acid protonated methane, a carbon with five hydrogens and a positive charge. Cryogenic infrared spectroscopy is revealing how this species behaves as it "morphs" between isoenergetic structures and could provide new clues as to how cosmic reactions occur.

A novel approach to determining enantiomeric excesses in pharmaceutical reaction schemes based on NMR has been developed by French chemists. The researchers exploit the intramolecular dynamic processes of bi-aryl derivatives of compounds of interest using deuterium NMR. The weak ordering revealed by a polypeptide chiral liquid crystal solvent can be used to calculate activation energies for the conformational exchanges. Philippe Lesot and colleagues at the Université de Paris-Sud envisage using a series of chiral atropisomers to determine the effect of the position and size of substituent on the internal rotation barrier of small molecules.

Namenda - memantine hydrochloride - can slow the development of symptoms in patients with moderate to severe Alzheimer's disease for at least a year, according to a multicenter study carried out by US researchers. Barry Reisberg of New York University and colleagues have verified that this medication "continues to be beneficial and is safe with remarkably few side effects". Namenda, 1-amino-3,5-dimethyl adamantane hydrochloride, was approved initially in October 2003 by the Food and Drug Administration based partly on a 28-week placebo-controlled clinical trial of 252 people. The new results - an open label extension - followed up 175 patients, 80 of whom had received placebo in the initial trial. The follow-up trial was funded by the drug's German distributor Merz Pharmaceutical.

The formation of the 1:1 complex between water and carbon dioxide could provide climatologists with important insights into the behavior of these atmospheric molecules, according to Patrick Chaquin of the Pierre and Marie Curie University and colleagues. He and his team have isolated the 1:1 complex of water and carbon dioxide in a nitrogen matrix and carried out an IR analysis using isotopic substitution of water. Their results suggest that there are two very weak complexes that can form each with an almost T-shaped structure in which the carbon atom is bonded to the water oxygen. Such chemical interactions could be important clues to understanding the role of these molecules in the so-called greenhouse effect.