An extract from brown algae – seaweed – could give rechargeable lithium-ion batteries a boost by allowing silicon nanopowder to be used as a high-capacity alternative to graphite electrodes. The potential improvement is almost an order of magnitude boost, the researchers say.
Fluorine in organic chemistry is an important topic across the synthetic pharmaceutical, agrochemical and materials areas because switching out hydrogen atoms selectivity for this element allows chemists to tune the reactivity of specific groups within a given molecule.
Now, chemists in Switzerland have turned to fluorine to help them make specific carbon-carbon bonds. The formation of C-C bonds is one of the most important steps in organic chemistry for the construction of complex molecules from simpler sub-units. Perhaps most important among the tools for building C-C bonds is the Friedel-Crafts reaction. It involves an attack on a carbocation-type substrate generated by a Lewis acid by the electron-rich pi-clouds of aromatic rings leading to an alkylated or acylated version of the aromatic ring.
A complete field within organometallic chemistry has emerged to support the Friedel-Crafts C-C endeavor. However, the instability of the phenyl ion means that coupling aromatic group to aromatic group using this chemistry has until now required a range of metal-mediated approaches. Jay Siegel and his colleagues at the University of Zürich hoped to simplify the schemes and avoid the need to use often expensive metal catalysts.
They have used Lewis acid activation of aryl fluorides to make biaryls intramolecularly. The Lewis acids are silicon cations generated by catalytic super acid, he told Chemistry Views. In a synthetic methods paper published in Science, Siegel and colleagues build on research published in Angewandte Chemie in which they revealed the C-F activation and work also published in Angewandte and JACS on the structure and properties of the silicon cations.
Siegel explains that this is a, “physical-organic success story of looking at a fundamental reactive intermediate and ending up with a new synthetic methodology.” He adds that, “Given that people put CF bonds into molecules to make them more inert, it is special that our method targets exactly these sites.”
Allemann, O., Duttwyler, S., Romanato, P., Baldridge, K., & Siegel, J. (2011). Proton-Catalyzed, Silane-Fueled Friedel-Crafts Coupling of Fluoroarenes Science, 332 (6029), 574-577 DOI: 10.1126/science.1202432
- Researcher lists more than 4,000 components of blood chemistry – After three years of exhaustive analysis led by a University of Alberta researcher, the list of known compounds in human blood has exploded from just a handful to more than 4,000.
- Bone drug zoledronic acid may help prevent spread of early lung cancer – A drug that is currently used to help treat bone metastases in patients with lung cancer could also be useful at an earlier stage of treatment, to prevent the cancer from spreading in the first place, Italian researchers have found.
- Elusive form of iron captured – Researchers in the US and Germany have synthesised and characterised an iron nitride compound that reacts with water to produce high yields of ammonia under mild conditions. The work could help elucidate the mechanisms behind iron-based catalysts, both for industrial and biological ammonia production, which could allow for cheaper non-toxic catalysts.
- Diagnosing diseases with CDs – A digital compact disc integrated with a microfluidic device to analyse cells has been developed by scientists in the US. The disc can be inserted into a standard computer disc drive for analysis and could be used to diagnose diseases.
- Bendy batteries a step closer – Scientists from Korea have found that with the use of graphene nanosheets, the fabrication of bendable power sources is possible.
- Mystery of natural sunscreen solved – Spanish scientists have established how natural products protect plants from sun damage. The compounds could be used as active ingredients in sunscreens. Using computational techniques on palythine – a compound found in coral – as a model compound, Diego Sampedro at the University of La Rioja, Logroño, investigated what happens to the molecule after it absorbs UV light.
- Vertex Unveils Exciting Data for Cystic Fibrosis Drug – In one of those rare cases of good science translating directly into good medicine, Vertex Pharmaceuticals yesterday unveiled positive results from a Phase III trial of VX-770, a small molecule that treats the underlying defect of cystic fibrosis.
- IMEC creates flexible microprocessor with organic semiconductors — computational clothing right around the corner – Organic semiconductors have been teasing us with the possibility of computationally-inclined clothing for years, but until now we could only dream about our pants being the computer. That dream is closer to reality than ever, as researchers from IMEC have created a cheap (potentially 1/10th the cost of silicon chips), bendable microprocessor by layering a plastic substrate, gold circuits, organic dielectric, and a pentacene organic semiconductor to create an 8-bit logic circuit with 4000 transistors.
- Mapping brain networks – US scientists have created a model of the ring-shaped networks of neurons in the brain, which could help researchers to understand small changes within diseased brain cells.
- Seaweed recruited in fight against malaria – Compounds found in seaweed have shown anti-malarial properties, killing even drug-resistant malaria parasites
Robert Slinn selects ten from the latest chemistry news for Reactive Reports.
- Reprogrammed stem cells hit a roadblock – An international study shows that reprogramming cells leads to genomic aberrations.
- Blocking enzyme cut cancer spread – Scientists at the UK's Institute of Cancer Research have prevented breast cancer spreading to other organs in mice by blocking a chemical. In their experiments, they showed that blocking the enzyme LOXL2 prevented metastasis.
- Warring molecules keep the colon cancer-free – KU associate professor of molecular biosciences Kristi Neufeld and her graduate student Erick Spears study how a molecule, a protein called APC, suppresses colon cancer. In a recent article in the Journal of Biological Chemistry, they explain how a drug might someday treat the disease by blocking the action of one of APC’s molecular opponents.
- Nanolasers grown on silicon allow bottom-up nano-optoelectronic integration – Researchers at UC Berkeley have developed a way to grow III-V nanolasers on silicon, demonstrating the potency of bottom-up nano-optoelectronic integration.
- Microbially produced ferrous iron may decrease technetium concentrations in groundwater – Microbially produced ferrous iron may decrease technetium concentrations in groundwater, it has been found.
- Lithium-ion battery with new chemistry could power electric vehicles – Researchers have developed a novel type of lithium-ion battery with an anode and cathode that involve new, advanced battery chemistries, greatly improving the battery’s performance and likely making it suitable for electric vehicles.
- Breathe, and a nanogenerator will power your pacemaker – Previous research has showed that high performance piezoelectric ceramics PZT (lead zirconate titanate) could be printed as nanoribbons onto biocompatible and flexible substrates for applications such as harvesting energy from human motion like walking or breathing ("Electricity-generating silicone implants could power electronic devices"). Researchers now report that they have succeeded in fabricating stretchable nanothick ribbons of piezoelectric PZT.
- Nanotechnology-based solutions for oil spills – Conventional techniques are not adequate to solve the problem of massive oil spills. In recent years, nanotechnology has emerged as a potential source of novel solutions to many of the world's outstanding problems. Although the application of nanotechnology for oil spill cleanup is still in its nascent stage, it offers great promise for the future. In the last couple of years, there has been particularly growing interest worldwide in exploring ways of finding suitable solutions to clean up oil spills through use of nanomaterials.
- Antifungal compound found on tropical seaweed has promising antimalarial properties – A group of chemical compounds used by a species of tropical seaweed to ward off fungus attacks may have promising antimalarial properties for humans. The compounds are part of a unique chemical signaling system that seaweeds use to battle enemies — and that may provide a wealth of potential new pharmaceutical compounds.
- Brain imaging reveals pessimism as self-fulfilling prophecy – By manipulating your expectations, you can double or halve the potency of the drugs you take. Scientists show that a gloomy outlook towards medical treatment may decrease the effectiveness of the drugs – based on brain images of thoughts, feelings, and past experiences.
Another high yielding news day from Robert Slinn for Reactive Reports in his regular column: Slinn Pickings.
- Math may help calculate way to find new drugs for diseases – Using mathematical concepts, Princeton researchers have developed a method of discovering new drugs for a range of diseases by calculating which physical properties of biological molecules may predict their effectiveness as medicines.
- A Second Pathway for Antidepressants – Berkeley Lab researchers developed a unique cell-based fluorescent assay that enabled them to identify a means by which fluoxetine, the active ingredient in Prozac, suppresses the activity of the TREK1 potassium channel. TREK1 could be an important new target for antidepressant drugs.
- New explanation for heart-healthy benefits of chocolate – In time for the chocolate-giving and chocolate-eating fest on Valentine's Day, scientists are reporting discovery of how this treat boosts the body's production of the "good" form of cholesterol that protects against heart disease. Polyphenols in chocolate rev up the activity of certain proteins, including proteins that attach to the genetic material DNA in ways that boost "good" cholesterol levels.
- Save messengers – Modified mRNAs open up new therapeutic possibilities – Defects in the genome are the cause of many diseases. Gene therapy – direct replacement of mutant genes by intact DNA copies – offers a means of correcting such defects. Now a research team based at the Medical Center of the University of Munich, and led by Privatdozent Dr. Carsten Rudolph, has taken a new approach that avoids DNA delivery. The team shows for the first time that chemical modification of mRNAs (the metabolically active molecules derived from genomic DNA that programs protein synthesis) provides a promising alternative to DNA-based procedures.
- The brain knows what the nose smells, but how? – Mice know fear. And they know to fear the scent of a predator. But how do their brains quickly figure out with a sniff that a cat is nearby?
- Siemens prepares to build molten-salt power plant – Siemens is to build a test power plant that will operate with molten salt as the heat-transfer medium.
- Engineers grow nanolasers on silicon, pave way for on-chip photonics – Engineers at the University of California, Berkeley, have found a way to grow nanolasers directly onto a silicon surface, an achievement that could lead to a new class of faster, more efficient microprocessors, as well as to powerful biochemical sensors that use optoelectronic chips.
- Using mining by-products to reduce algal blooms – CSIRO research has shown that some mining by-products can be effective in preventing nutrients from entering river systems, thereby reducing the potential for algal blooms.
- Clay-armored bubbles may have formed first protocells – A team of applied physicists at Harvard's School of Engineering and Applied Sciences (SEAS), Princeton, and Brandeis have demonstrated the formation of semipermeable vesicles from inorganic clay. The research shows that clay vesicles provide an ideal container for the compartmentalization of complex organic molecules.
- Targeting memory loss – A new treatment for Alzheimer's disease has been developed by Canadian and US scientists. Chris Orvig at the University of British Columbia, Canada, and colleagues incorporated a thioflavin dye molecule with pyridinones. The dye is used as a marker for detecting amyloid protein deposits in tissues – a sign of neurodegenerative disease – and pyridinones cross the blood-brain barrier and trap the metal ions that cause the Alzheimer's disease
Robert Slinn refluxes the chemistry news and extracts a goodly yield for Reactive Reports in his regular column: Slinn Pickings.