ChemWeb Newsletter

Not a subscriber? Join now.September 13, 2004


The Alchemist Newsletter is back from a well deserved vacation and a move from London to Los Angeles. Now published by ChemIndustry, the newsletter and the ChemWeb site will continue to be offered as free services. We are working on some exciting new features for both ChemIndustry and ChemWeb and will notify our users by email in the weeks to come. Please contact the with your comments and suggestions.

In this, the third issue of the all-new Alchemist, David Bradley discovers how tiny zinc oxide needles can capture whispers of light, and how feeding an antioxidant to plants could turn them into robust metal miners. Also in this issue, we learn about the toxic flame retardants coming straight off the supermarket shelves, and how NMR spectroscopy is revealing the hidden signal in catalytic hydroformylation. Finally, a molecular rotor brought back childhood memories of a toy gyroscope and pointed to the future of components for molecular scale machines.

Takanori Shima and John Gladysz of the University of Erlangen-Nuremberg have designed and built the first fully enclosed molecular rotor system, which resembles a gyroscope. The structure, confirmed by crystallographer colleague Frank Hampel, consists of an iron tricarbonyl core surrounded by a framework of three methylene chains whose length can be varied. The iron tricarbonyl core functions as the rotating disk and center of the gyroscope, say the researchers, with the methylene chains acting as the spokes. Such materials emulate nicely the function of macroscale objects such as the real gyroscopes and could one day become essential components in supramolecular machines.

A microscopic "whispering gallery" for light has been created by saturating molten gold with a zinc oxide plasma to create an array of tiny spires. The material carries light of different wavelengths like a whispering gallery carries sound. Visitors to the rotunda in London's St. Paul's Cathedral can hear each other's whispered conversations from one end of the gallery to the other because of the way the walls curve. Now, Marius Grundmann of the University of Leipzig in Germany and his team have fabricated and analyzed a tiny whispering gallery that has a similar effect to the rotunda but with visible light rather than sound waves. The nano-gallery is built from tiny needles of zinc oxide with a hexagonal cross section that are each just 800 nanometers long. The researchers suggest that their needles will help researchers understand the behavior of light at nanoscales, an important step in creating nanolasers for quantum data transfer, microscopy, and lithography.

The antioxidant glutathione can help certain plants to thrive on soils containing enough metal ions to kill most other plants according to researchers at Purdue University writing in the September issue of research journal The Plant Cell. The work of David Salt and John Freeman could provide a new approach to using plants in the bioremediation of metal-contaminated sites, such as old industrial sites and other brownfield areas. "We were able to clearly establish for the first time that plants that create and accumulate high cellular levels of glutathione are much more nickel tolerant," explains Salt. The finding could be useful to researchers hoping to use plants in phytoremediation for clean-up or in "phytomining" to extract useful metals from the soil.

A mechanistic study of one of the most important industrial reactions, hydroformylation, is providing new understanding of the process. The UK team carrying out the work has used an NMR approach to detect products through signals that are 30,000 times stronger than usual. To help them work out the details of how metal catalysts work in detail. According to Simon Duckett and colleagues at the University of York and researchers at Sasol Ltd in St Andrews, Scotland, "The rewards of achieving a greater understanding of such mechanisms are dramatic, leading to significant improvements in atom efficiency and hence fulfilling the chemist's desire to make a positive contribution to today's greener world".

Flame retardant chemicals, PBDEs (polybrominated diphenyl ethers), have been found in foods taken straight from supermarket shelves in Dallas, Texas, according to a research paper published this month in the journal Environmental Science & Technology. PBDEs were recently reported in the milk of nursing mothers in the USA, such halogenated compounds resemble polychlorinated biphenyls (PCBs) in terms of their chemical and toxicological profiles. The latest findings suggest that food may be a key source of the contamination measured in people around the world.