The Alchemist Newsletter: October 28, 2009

This week, The Alchemist learns how to stick methane molecules to metals without breaking C-H bonds and how to make impossible carbene catalysts without the usual prerequisite of an attendant metal center. Another seeming impossibility comes to light - a new microscopy technique for visualizing non-fluorescing biomolecules using stimulated emission. An exchange program leads to a new way to make nanoscopic tools from tiny wires of cadmium sulfide, we hear, while an extract of grape skin shows promise as a novel therapy for sickle cell anemia. Finally, a young medicinal chemist receives a prestigious ACS fellowship in organic chemistry.

back to top

Bonding with methane, it's a gas

The first stable sigma-methane complex formed between methane and a metal center without breaking any C-H bonds has been synthesized by chemists in the US. Maurice Brookhart, Cynthia Schauer and colleagues at the University of North Carolina and University of Washington, have prepared rhodium-methane complexes that avoid the problems that arose in earlier efforts and lead to materials that are much longer lived. Schauer confesses to a chemical cheat, explaining that the team used a strong acid to protonate a rhodium methyl complex and produce the methane ligand within the coordination sphere of the metal center, rather than introducing methane from solution.

Methane all bound up

back to top

Making impossible catalysts

A group of previously inaccessible catalysts - abnormal N-heterocyclic carbenes - have been synthesized by Guy Bertrand and his team at the University of California, Riverside. Carbenes are usually unstable and readily form metal-carbene complexes with catalytic activity. Trouble is the metals used in metal-carbene complexes by the pharmaceutical require expensive metals such as rhodium, gold, platinum or palladium. Now, Bertrand's team has successfully created "aNHCs" that are metal-free and can be used subsequently to make any desired complex. The work could have a huge impact on the field of catalysis.

New Molecules Created by UC Riverside Chemists Have Wide Applications

back to top

Micro light

Non-fluorescent molecules can be visualized with a light microscope thanks to a new technique developed by researchers at Harvard University. The method builds on stimulated emission, first described by Albert Einstein in 1917, and used in lasers. Wei Min, Sijia Lu, Sunney Xie, and co-workers at Harvard demonstrated for the first time that such emission can be used to produce contrast in molecular microscopy. The method could be used to image otherwise invisible biomolecules such as hemoglobin, cytochrome, and melanin in living cells and organisms, the team reports in Nature.

Seeing Molecules With A New Light

back to top

Nano exchange program

Cation exchange can be used to transform nanoscopic wires into useful tools, according to a team of engineers at the University of Pennsylvania. Ritesh Agarwal and colleagues used chemical techniques to convert single-crystalline cadmium sulfide nanowires into composition-controlled nanowires, core-shell hetero structures, metal-semiconductor super-lattices, single-crystalline nanotubes and metallic nanowires. The study provides the basis for manufacturers to assemble tiny circuits and so electrically connect nanoscale structures using self-assembly processes, the team says.

Penn Study: Transforming Nanowires Into Nano-Tools Using Cation Exchange Reactions

back to top

Grape skin against sickle cell

Medical College of Georgia researchers say that a polyphenol extracted from grape skin looks promising as a novel treatment for sickle cell anemia. Resveratrol has been found to induce production of fetal hemoglobin, which decreases the "sickling" of red blood cells and reduces the painful vascular episodes associated with the disease, according to Davies Agyekum and colleagues. The anticancer agent hydroxyurea has shown similar benefits, but Agyekum suggests that therapy based on resveratrol might be "easier" on patients and have fewer side effects.

Red grape skin extract could be new treatment for sickle cell disease patients

back to top

Med chem award

Alison Donnelly, a medicinal chemist at the University of Kansas, has been awarded a $26,000 fellowship to undertake research into cancer. Donnelly is one of eleven graduate researchers in the US to receive this American Chemical Society fellowship. Donnelly majored in chemistry and modern languages and literatures but her ambitions were focused on medicinal chemistry. "I was always interested in organic chemistry," she said. "It's only so much that you can make molecules. But for what? The idea of medicinal chemistry was a draw for me because it's making molecules with a purpose." Fewer than five medicinal chemists have received the organic chemistry awards in the last two decades.

Medicinal chemist receives fellowship

back to top