Chemistry – Page 46 – David Bradley

Branching out into optics

Dendrimeric molecules are multiply branched compounds that chemists have investigated keenly for their potential applications in medical diagnostics, molecular recognition, catalysis, and photoactive device engineering. Now Mark Humphrey of the Australian National University in Canberra and colleagues have developed organometallic versions of these compounds that are more stable than others. They investigated alkynylmetal complexes because of their potential to form materials with non-linear optical characteristics. Novel NLO materials will be crucial for the generation of opto-electronic computational and communications devices as well as in new types of sensor protection from laser threats.

Read on…

Crystallising thoughts on bird flu

UK researchers have determined the X-ray structure of a key protein of the avian influenza virus that reveals a peculiarity that might prove the Achilles’ heel of bird flu and allow new potent drugs against the disease that could stave off a flu pandemic.

H5N1 virus is named for the particular haemagglutinin (H) and neuraminidase (N) proteins that are found on the viral coat. Haemagglutinin allows the viral particles to bind to and infect host cells, while neuraminidase helps the virus to escape infected cells and attack new ones. There are 16 H’s and 9 N’s in known variants on the influenza type A virus.

It is the neuraminidases that are the target for drugs such as oseltamivir (Tamiflu) and zanamivir (Relenza). The trouble is, N1 is not the exact target for which they were designed. Rather the design of these drugs was based on neuraminidases N2 and N9 found in other influenza type A strains. H5N1 itself resides in a genetically distinct group. Structural information from this group could be critical to producing drugs that are resistant to emerging resistance in influenza.

Read the full story in my latest news round up at spectroscopynow.com

Nervous analysis

Chemical communication between nerve cells underlies brain functions, such as the control of sensory and motor processing, memory and learning. Monitoring neurotransmitter secretion is crucial to studying and understanding how the brain works. Various research teams have endeavoured to develop techniques for monitoring neurotransmitter release at the single-cell level, according to researchers in The Netherlands only invasive methods such as electrophysiological techniques and fluorescent probe labelling have provided adequate temporal and spatial sensitivity. These limits suffer from being limited to specific analytes.

Now, the researchers have turned to a specialist spectroscopic technique to develop a new approach to monitoring neurotransmitters that is non-invasive and side-steps the issue of analyte limitations.

Read the complete story in SpectroscopyNOW.com

High performance spectroscopy

High performance liquid chromatography (HPLC) is usually the technique of choice for separating and analysing complex mixtures of small molecules in laboratories around the globe. As such, a whole range of specialist materials for particular types of analyte have been developed. French researchers, however, have now developed a novel approach to separation and analysis based on NMR that uses a simple solid support, such as porous silica gels.

Guilhem PagÃ¨s, Corinne Delaurent, and Stefano Caldarelli of the University of Provence and Paul CÃ©zanne in Marseille, France, recently developed an alternative for identifying components in a mixture that avoids the complexities of chromatography and relies instead on solid-enhanced diffusion-based NMR.

“The determination of the components of assemblies of small molecules is an extremely common task in chemical labs,” the researchers say. A method that mimics part of the chromatography process can they explain achieve good separation for certain types of common mixture but using only very simple chromatographic materials, which not only simplifies the analytical process but is far less expensive than employing sophisticated materials.

More…

Photochemistry without light

Infrared and nuclear magnetic resonance spectroscopy are anything but child’s play, but now US chemists have used these techniques to follow the chemistry of “light sticks” and to develop a light-free version of photochemistry. This contradiction in terms could be exploited in a remote cure process for photopolymers, they say, allowing inaccessible cracks in pipes, joints or containers, to be sealed as well as having other practical applications in coatings, paints, varnishes, adhesives and sealants.

Light sticks hold children’s parties in awe with their eerie yellow-green glow as well as providing emergency lighting without electricity or a naked flame. The chemistry taking place when the stick is “snapped” and the materials mix involves oxalyl chloride and hydrogen peroxide reacting in the presence of a fluorophore, which emits light as the reaction proceeds.

Read the full story in the latest news round up from David Bradley on SpectroscopyNOW.com

Periodic Post

Periodic table of sex

Mosts chemists get to see some wacky periodic tables during their careers – circular ones, spiral ones, ones that rearrange all the elements etc etc. Then there are the foody ones and then there are the giant periodic tables, the arty farty ones, the online version, the flash table.

And, then there’s the periodic table of sex.

I didn’t think it was real at first, but several sciencebase visitors have been searching for this incredible object during the last few days, so I thought I’d uncover the truth. Apparently, just such a PT exists, its elementary in the most lewd way, but is available from Amazon. Apparently, allposters.com have stopped selling it, so I’d grab one while you can: Periodic table of sex

It’s not every post I get to categorise as chemistry, sex and geek all at the same time, but this one was simply begging for it. I hate to think what good-ole Dmitri Mendeleev would have made of it though, but surely it’d make the perfect gift for the chemistry student in your life. Wouldn’t it?

European Chemistry Congress

The very first European Chemistry Congress starts Sunday and runs till the end of the month. The event is being held in Budapest, Hungary, at LorÃ¡nd EÃ¶tvÃ¶s University, and promises to be an astounding affair showcasing chemical sciences in Europe and bringing together chemical and molecular scientists from industry, academia and government institutions across Europe and from around the world.

The conference has been organised by EuCheMS (European Association for Chemical and Molecular Sciences, formerly FECS) and is co-sponsored by GDCh, RSC and SFC with an old friend of mine, Professor Jean-Marie Lehn heading up the scientific committee.

It’s a long time since I wrote about the rise of European chemistry in a feature article for Science magazine (Science 18 June 1993 260: 1738-1739), and it seems that this conference has been a long time coming. But, like they say, better late than never.

ChemWeb Alchemist

In this week’s Alchemist news round up: oscillating carbon fibres could usurp silicon in the world of microscopic video, find out how a sugar molecule seen only on anthrax spores could help defeat the bacterium in the event of a bioterrorism attack. We also report on how the US government has asserted that levels of dioxins and related compounds have fallen in meat and poultry and we discover how to make see-through silver.

Finally, a new surfactant allows oil and water to be mixed and unmixed on demand and could mitigate oil spill disasters. Here’s the skinny: Canadian chemists have synthesised a new surfactant that allows oil and water to be mixed and de-mixed on demand depending on whether carbon dioxide or air is bubbled through the mixture.

Generate molecular formula

A rather common search on the sciencebase site seems to ask how to generate a molecular formula. Well, the method I use is to go straight to ChemSketch and fire up ACD/Dictionary, type in the name of the compound I want to produce and paste it into the ChemSketch window. That gives you the everyday 2D structure. A quick click of the “3D Viewer” button does what it promises to do and opens the molecule as a 3D view. At this point, it’s still flat and has to be optimised, so the “3D optimization” button is next. That renders the molecule as a three-dimensional molecular structure. Now, save as a mol file and as a ChemSketch structure.

Now, I follow one of several paths at this point depending on what use I am to put the molecular formula. If it’s to illustrate a scientific piece I’d often be simply using the 2D version. But, if I want something a bit flashier I’ll usually use the 3D view and tweak the settings to change background colour, add or remove hydrogen atoms, or re-render it as a space-filling or ball and stick molecule, depending on which format will best get across the chemical message.

Alternatively, I may shut ChemSketch altogether and re-open the mol file in Diamond from Crystal Impact, which can produce wonderful pseudo photographic quality molecular structures. And, if these aren’t good enough, the next step is to do a full 3D rendering in Pov-Ray, which provides scenic backgrounds, quasi-shadowing, and other wonderful effects to produce a beautifully metallic textured molecule hovering in space, for instance.

Next stop, Chemistry Central

A new open access site for chemists – Chemistry Central – launches today as part of the newly announced Open Access Central group of sites from the makers of BioMedCentral.

CC collates peer-reviewed research from a range of open-access journals and makes available the original research articles as soon as they are published.

Deputy Publisher and former chemist Bryan Vickery explains the motivation, “We have seen increasing interest from chemists in the open access publishing model and, having launched two chemistry-specific titles in the last 18 months, the time seemed right for BioMed Central to create an open access publishing website to meet the needs of chemists,” he says.

On the CC roster are OA articles from Geochemical Transactions, the Beilstein Journal of Organic Chemistry, and chemistry-related articles from BMC Pharmacology, BMC Biochemistry, and BMC Chemical Biology.

As well as viewing the latest research highlights and content from featured journals, the Chemistry Central site provides a forum for the discussion of articles, and users can subscribe to email alerts.

“The BioMed Central team has created an open access publishing website to meet the needs of chemists,” Vickery told Sciencebase, he adds that, “The initial launch phase of Chemistry Central has three main thrusts. Firstly, to raise awareness among chemists that a credible open access alternative to traditional scholarly publications exists, that will disseminate their work more widely and increase readership and use. Secondly, it showcases the chemistry research which BioMed Central’s journals are already publishing, proving their technical suitability for chemistry research. Thirdly, by launching Chemistry Central we are offering our open access publishing services to those who wish to launch new open access journals in chemistry, or to transfer existing journals to this model.”

For a totally unrelated discussion forum check out this link where you can share your thoughts on almost anything, it seems, from news and sport to photos and music.