ChemWeb Newsletter

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In this week's issue a new definition of the hydrogen bond could lead to major textbook revisions and open up new chemical vistas. We learn that a turbo transfer can be used to synthesize useful nucleosides and organic vegetables are no higher in healthy nutrients than conventional crops. The world of materials could make "Star Wars" type holographic movies a reality and a weed might be the biofuel industry's saving grace in the food versus fuel debate. Finally, accolades for DOE biochemist Richard Smith.

New advances in materials science have led to the demonstration of a color holographic display that can depict a scene in another location and be updated in close to real time (refresh rate is once every two seconds). The system known as three-dimensional (3D) telepresence was reported in the journal Nature and holds great promise for applications in the entertainment industry and in telemedicine as well as potentially fulfilling the dreams of a generation of fans of the Star Wars movies and actor Sir Alec Guinness. A photorefractive polymer is used as the recording material and a two-dimensional image is recorded from various angles using 16 Firewire cameras in one location and sent to another using a network connection where it is "printed" with the hologram set-up. The material is a copolymer with a polyacrylic backbone to which are attached pendant tetraphenyldiaminobiphenyl (TPD) and carbaldehyde aniline (CAAN) groups in the ratio 10:1 (TPD/CAAN). Plasticizer, 9-ethyl carbazole (ECZ), lower the glass transition temperature and facilitates chromophore alignment.

Pennycress, also known as stinkweed and frenchweed grows widely in the American Midwest, it completes its lifecycle in late spring and so does not interfere with the growth of soy and corn crops. This horticultural characteristic could make it the perfect plant to grow for biofuel because it neatly sidesteps the issue of displacing food for fuel. Terry Isbell and colleagues at the new crops and processing technology group at the National Center for Agricultural Utilization Research at Peoria, in Illinois, say the seeds of pennycross produce 36% oil by weight and the plant grows at a density of one tonne over an area of just 4000 square meters. Pennycress seed oil contains a range of fatty acids from 16-carbon to 24-carbon chain length.

R&D Magazine has honored biochemist Richard Smith of the Pacific Northwest National Laboratory as its 2010 Scientist of the Year for his many significant contributions to science in fields as diverse as Parkinson's disease, cancer and biofuels. Described as "creative," "innovative" and "adventurous" by his colleagues, Smith has, since the 1980s, pushed technological advancements bringing analytical chemistry techniques into the domain of microbiologists and medical researchers. "I'm surprised and pleased at the honor," said Smith. "And I'm especially grateful to the incredibly talented team of researchers at the lab whom I have been able to work with."

The International Union of Pure & Applied Chemistry, IUPAC, has issued chemists with an ultimatum: it intends to break all fleeting, electrostatic hydrogen bonds and remake them as something more akin to covalent bonds. Chemists have until the end of March 2011 to offer their opinions on the new definition of the hydrogen bond. Emerging evidence about the nature of hydrogen bonds suggests that this important phenomenon is underpinned by a degree of electron sharing that the current definition does not accommodate. The new definition will also extend the focus beyond electronegative atoms allowing it to encompass a much wider range of intermolecular and intramolecular connections.

Thomas Carell and colleagues at Munich's Ludwig Maximilians University, Germany, have introduced a novel method for synthesizing transfer RNA (tRNA) nucleosides. tRNA nucleosides are modified genetic bases and include deazaguanosine nucleosides, which have antibacterial, antifungal, antiviral, and anticancer activity. The team has applied a Turbo-Grignard-based approach to their synthesis and demonstrated an unprecedented level of control of the products they can derive from a common intermediate, thus overcoming the problem of multiple reactive groups in the deazaguanosine nucleosides. Specifically, the team was able to synthesize the PreQ1, PreQ0, and archaeosine.

It's a matter of contention that "organic" food products are intrinsically healthier than those grown with modern farming techniques using pesticides and synthetic fertilizers. Now, Pia Knuthsen and colleagues in Denmark have demonstrated that in one sense organic onions, carrots, and potatoes really are no healthier as they do not have higher levels of healthful antioxidants. The researchers analyzed polyphenolic antioxidants in onions, carrots and potatoes grown using conventional and organic methods and found no differences in concentrations. "On the basis of the present study carried out under well-controlled conditions, it cannot be concluded that organically grown onions, carrots, and potatoes generally have higher contents of health-promoting secondary metabolites in comparison with the conventionally cultivated ones," the team states.