Chemistry – Page 44 – David Bradley

Trapped particles and solar energy

Spanish researchers have trapped tiny clusters of titania in the pores of zeolite. They hope to develop a new class of photovoltaic material for solar energy conversion. Ultimately, zeolite-entrapped titania will be less expensive to manufacture, tougher, and more efficient than conventional silicon-based materials.

Titania-based photovoltaics are soon to enter the solar energy market but they suffer from several drawbacks. For instance, the small size of the particles used to make the light-sensitive layer means that they are not highly electrically conductive. Moreover, at less than a few nanometres, titania particles can only be activated by deep ultraviolet light and so don’t exploit the full spectrum of sunlight. Hermenegildo GarcÃa of the Polytechnic University of Valencia and colleagues hope to change all that, Although they need to improve the photo efficiency of their materials by at least an order of magnitude, the adaptability of zeolites means this should be possible.

Read on…

Pubchem discussion

Gary Wiggins alerted CHMINF-L subscribers to the launch of a listserv discussion group for Pubchem users:

“The PUBCHEM-L listserv provides a forum for users of the NIH PubChem
database (http://pubchem.ncbi.nlm.nih.gov/) to discover how to make the
best use of the database,” he told us.

Wiggins also provided a warning to users thinking of flaming the makers of PubChem. “It is not intended to be a platform for political debate on whether it is right or wrong for the US government
to create such a database,” he said, “Appropriate questions or comments to be submitted to the list include methods of searching, descriptions of auxiliary tools to enhance the utility of PubChem searches, how best to interface with other systems, how PubChem compares with other sources,
etc.”

Visit Pubchem-L to search the archives and to subscribe.

Nobel Prize in Chemistry 2006

Roger Kornberg will receive this year’s Nobel Prize in Chemistry for his work on unzipping genetic transcription. More info on the Nobel site and my write-up next week under the Intute Spotlight and an XRD-oriented version to appear in spectroscopynow.com.

This just in from the American Chemical Society (19h00 UK time):

‘The research Dr. Kornberg did will help open the door to understanding and treating many human ailments, including cancer, heart disease and inflammation, and will help scientists better understand stem cells and their potential for therapeutic applications,” said Ann Nalley president of the American Chemical Society and a chemistry professor at Cameron University, in Lawton, Oklahoma. ‘This Nobel Prize also underscores the key role of chemistry in the scientific research into genetics. In order to take the first actual pictures revealing how the genetic information stored in genes is copied so that the body can use it, Dr. Kornberg used a mainstay chemical technology called x-ray crystallography.”

She adds that, ‘Chemistry has had a key role from the very onset of the genetics revolution. It has provided the core technologies that enabled molecular biology and biotechnology to leap ahead. I am delighted that this Nobel Prize highlights chemistry’s role in such an important field of research.'”

I couldn’t agree more, but it would be nice if the Chemistry prize were more geared to straight chemistry, especially as the Medicine prize was awarded this year for essentially similar research into RNA interference, which could just as easily be labelled “Chemistry”. Oh well.

2, 4, 6, 8 – team oxygen

Nature described this finding as “surprising, elegant, and entirely useless”. Well, the journal is half right. Solid elemental oxygen is not thought to exist anywhere on earth or even elsewhere in the universe under the immense pressures created by Malcolm McMahon and Paul Loubeyre. They and their colleagues put the squeeze on solid oxygen, which forms deep red crystals at above a million atmospheres. They used various techniques to determine the structure of this new material and found that oxygen atoms team up to form clusters of eight in the solid. A seemingly esoteric discovery you might think.

However, the new understanding gained of materials under pressure could lead to new efficient rocket fuels or superhard materials formed from oxygen, nitrogen, or carbon that beat diamond for toughness.

Moreover, the results suggest that hydrogen might also form metallic crystals of a similar nature to solid oxygen at 450 gigapascals (4.5 million times terrestrial atmospheric pressure). Such pressures exist at Jupiter’s core astronomers think. Under these conditions metallic hydrogen may behave as an exotic superconductor or superfluid. That finding may be elegant, certainly no longer surprising, but too perhaps even more useless!

Read the full story in SpectroscopyNOW.com

Chemical flickr

It was a tough call given how many photos there are of what those Stateside call a pharmacy or druggist, as opposed to a chemist in the UK, but I managed to track down a few chemists on flickr. Remember, regardless of appearances, chemists are always hot (it’s all those exothermic reactions).

Once again gender merging raises PC concentration.

Flickr Chemists

Grinning Don
Rhiannon
Lynn
Becky
Naser
Begoggled
Gregory
Cleopatra
Karl Pilkington
Little chemist

Any suggestions for the next round of hot science welcome…

Chemists escape browser lock down

WebME chemical structure drawing Is your browser so locked down that you can’t install any plugins or enable Java? Firewall refusing to cooperate with your molecules? Antivirus screaming at your structural efforts?

If so, then you probably find it rather difficult to run some of the chemistry drawing packages available for interactive use on the Web. There is an alternative.

Molinspiration Cheminformatics has released WebME, a molecule editor for creating
and editing molecules within a web browser that doesn’t need Java support and requires no plugins to be installed. The molecular editor is based on Web 2.0 Ajax technology and structure processing runs on serverside rather than on your machine.

The result is a web-based structure-input program with all kinds of potential that is not only platform independent but works with those locked down browsers.

Click to try WebME. In this implementation, the program is being used as the structure input for a molecular property calculator.

It may not have the depth of field of programs like ChemSketch and ChemDraw (yet), nor the bells and whistles of the many other structure packages available. But, the benefits to those behind restrictive user settings (in chemistry libraries for instance) are obvious.

The program is still in the beta stages of development, sitting at version 0.96 whatever that means. It seems nice and smooth to use though, quickly calculates properties and generates a Smiles string that you can then use elsewhere to search for your molecules. I hope they add InChI support soon though that’s the way to go for molecular searching these days.

There is, of course, another application that operates under similar general principles – PubChem sketcher (click the sketch button at PubChem.

Ironically small

An incredibly small item in Saturday’s Times announced that a Voluntary Reporting Scheme – established by DEFRA – in the UK to record and assess the risks posed by nanoparticles has been created. Scientists have welcomed the announcement, apparently. More likely, they are rather peeved that yet another layer of bureacracy has been added to their workload.

According to the paper, “Little is known of the potential risk to health by the creation through nanoengineering of altered particles.” No doubt, UK tabloids and scaremongers will jump on any future pronouncements as an admission of guilt once the first minute risks are revealed. Forgetting, of course, the enormous risks we face every day simply cross the road or jumping in our nanoparticulate-pumping cars.

Interestingly, there is a get out clause for scientists who may wish to peel back that bureacratic layer. The scheme is entirely voluntary!

So, if you’re an “evil scientist” intent on creating a doomsday scenario on a very, very small scale, then you needn’t worry about being risk assessed, just don’t add your research to the database.

Chemical structure lookup service

The NCI CADD Group headed by Marc Nicklaus and colleagues has just launched the Chemical Structure Lookup Service (CSLS). This web-based system allows one you to locate chemical structures in over 70 different public and commercial data sources. Stored within the system is information on over 30 million chemical structures and it provides a simple search interface for looking up chemicals by specific structure as well as by parent structure, and by various identifiers.

There are two mirror sites: http://cactus.nci.nih.gov/lookup/ and http://cholla.chemnavigator.com/lookup/

Smells like Godzilla

I once interviewed renowned odor theorist Luca Turin who described one particular group of chemicals as being the “the Godzilla of smells”. He added that “You can’t believe how awful they smell…They make you vomit your guts out instantly.” Thankfully, I never came across them when I worked in a lab, but I’m sure he’s right.

Of course, the reason that I never happened upon these compounds during my lab days is that they have such an offensive odor that mosts chemists side-step them when designing their syntheses. That’s a shame though because they have several distinct benefits missing from the properties list of other ingredients.

Now, Michael Pirrung and Subir Ghorai, of the University of California at Riverside have found a way to make a new family of isonitriles. Their approach uses low-risk starting materials and they work well in the kinds of chemical synthesis reactions in which existing compounds are not quite so good. But, more to the point, these isonitriles don’t make you vomit. Instead, that have rather pleasant odors of soy, malt, natural rubber, mild cherry and even caramel, according to the team.

A bad smell is usually an indication that something won’t be too good to eat though. A mild cherry and caramel reaction sounds almost tasty, but I would seriously not recommend making it a lab-time snack.

More on isonitriles in the latest issue of JACS.

Cheating agents

Sciencebase visitors commonly search the site for specific chemicals they’re interested in. Of course, I’d always recommend hoping over to Chemspy.com for structures, MSDS and other information. You can search PubChem, ChemFinder, ChemRefer, ChemIndustry and several other chem sites via the ChemSpy toolbox (bottom right, homepage, enter your keywords and click the database of choice)

Anyway, yesterday someone was looking for 2,4,6-tri(2-pyridyl)-1,3,5-triazine, so I did a quick search myself to see where the interest in this compound lay. Lots of search results came back, but one in particular caught my eye, this claw-like molecule is apparently a “cheating agent”, at least according to a patent that came up on an esp@cenet search. Now, unless the compound in question has gained some novel yet devious physiological properties, I’d have to assume they missed the “l” and that it’s actually a chelating agent that can grab on to metal ions with more than one of its own items with a claw-like grip, in fact. I could be wrong…