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August 06, 2009

IUPAC '09: Save the symbol!

Remember the latest addition to the periodic table, copernicium, element 112? Well the fall out from the name choice has begun.

The abbreviated symbol that discoverer Sigurd Hofmann chose was Cp. This hasn't been confirmed by IUPAC yet, and this is the body that has the say in the end, but it seems appropriate that here at the IUPAC congress that the discussion over this shortened symbol should be aired.

The problem is that for many synthetic chemists Cp already means something - it is used as a shorthand form for the cyclopentadienyl ring, a 5 carbon and 5 hydrogen ring that is aromatic like benzene and often used as a ligand.

So some chemists are inevitably unhappy about the use of Cp for another purpose. One of these is Paul Chirik from Cornell University who in his talk about main group chemistry apparently said he wanted to start a campaign to have the abbreviation Kp, not Cp used for element 112. This, apparently is etymologically correct, because Copernicus was actually Polish and his name was spelled Mikolaj Koppernigk.

Chirik assures me he said this in jest and is by no means an expert in this area. But I wholeheartedly encourage this kind of campaign! Come on chemists, stand up for the rights of cyclopentadienyl ligands! Kp vs Cp - what do you think?

Posted by Katharine Sanderson on August 06, 2009
Categories: International Union of Pure and Applied Chemistry 2009 | | Comments (0) | TrackBacks (0)

IUPAC '09: Thinking big to save the world

The plenary lecture this morning was by Peter Bruce, from the University of St Andrews, over on the east coast of Scotland. His message was an appeal to chemists to open their minds in order to save the world from climate change. Free yourselves from thinking of the immediate applications, he said, and this challenge can be faced. "The chemistry to tackle this is still going to be fundamental chemistry," he says. Chemists should forget the immediate technical challenges.

Stirring stuff. And he had some very good reasons for saying this. Bruce has spent many years looking at ion transport in polymer electrolytes, and along the way has invented a better way to probe the structure of these large crystalline polymers that are otherwise too large to get x-ray crystal structures of.

How can this help climate change? Well these fundamental chemistry advances have found their way into lithium batteries - the things that charge our laptops, mobile phones, as well as powering tiny implantable medical devices of the future.

Bruce is now looking at ways that might - eventually - make the charging and recharging process of batteries much much faster. This process involves lithium ions moving from one material to another. They travel one way when the battery is being used, and when it's plugged in again to recharge, they hop back over from whence they came. As many of you will know, this can take hours.

Bruce's work on solid crystalline polymer electrolytes could help. But to understand how these materials work their molecular-scale structure needs to be understood. The problem has been getting single crystals to do crystallography on. So Bruce developed a powder diffraction technique that worked a treat.

He's also spent a lot of time investigating why and how these crystalline polymers can conduct. The reason is that ions in crystalline polymers hop, which is very different to the way floppy non-crystalline systems work, he says. The conductivities they show are way too low for industry, he says, but doesn't much care. "Scientifically it opens up new avenues," he said. And curiosity has led his group to investigate other metals in the same group of the periodic table as lithium.

Next is the challenge of making the energy density of the materials better. To try and get a ten-fold improvement in energy, Bruce has developed a lithium-air battery, where oxygen from air reacts to start the ion motion. It's a neat idea, and you never know, it could work.

Posted by Katharine Sanderson on August 06, 2009
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August 05, 2009

IUPAC '09: posters and pink wine

Disaster struck at the poster session tonight. I thought that the session organisers had decided to extend the reach of refreshments provided to include rose wine (a summer drink) and I gladly took a glass full of the pink stuff. To my horror I discovered it was cranberry juice. Tsk.

Luckily, to calm my nerves I had the pleasure of talking to Charlotte Mallet a PhD student from the University of Angers, France. She explained to me that she was trying to take biomass - cellulosic waste from agricultural processes - and make electronic devices.

So far she has managed to make oligomers based on furans, derived from the fructose molecules she gets from the biomass. From this she can make an organic plastic and from that a transistor. The properties of this device aren't quite good enough for industry, Mallet says, because they have low mobility, which means they can't carry electrons very well. But she is working hard to improve this and hopes to have a news device by September.

I'm not sure how seriously this proposition will be taken in attempts to save the world from burning fossil fuels, but perhaps every little helps.

Posted by Katharine Sanderson on August 05, 2009
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IUPAC '09: Carbon capture conundrums

200px-Ethanolamine-3D-balls.png

Back in my youth, when deciding what subjects to study at school and university I wanted to make sure that I would come out versed in something that would be of use to the wider world, perhaps even do some good. I chose chemistry. It's clear from conferences like this that many chemists are interested in the subject for similar reasons.

Climate change is a big topic that chemists are tackling. This morning's session on carbon capture and storage being a good example.

This is a technology intended to clean up coal-powered power stations by scrubbing out carbon dioxide from flue gas, and compressing it to be stored elsewhere - anywhere but into the atmosphere.

There are a number of problems that chemists are looking at. Today kicked off with a talk by Gary Rochelle from the University of Texas at Austin. He took us through the major considerations that are needed for the solvent that is used to collect the carbon dioxide from the gas. The standard at the moment is something called MEA, monoethanolamine. Rochelle's fundamental physical chemistry calculations on this and other candidate solvents showed that there isn't a simple one-size-fits-all solvent. The considerations are: capacity of the solvent to hold carbon dioxide; how much the solvent degrades when heated; how fast the reaction is; how much heat it requires.

Some of these properties are better in different solvent, he says, which are again different in different plants. Another good candidate solvent looks to be piperazine.

Then we heard from Trevor Drage from Nottingham University, UK, about using solids not liquid solvents to strip out the carbon dioxide. His systems are a long way from being scaleable but show promise. On paper, he said, solid sorbets could reduce energy loading in the systems by 30 - 50%. These systems are amine polymers loaded onto porous silica-based materials, or basic nitrogen in an activated carbon matrix.

One area that is often overlooked, says Drage is the regeneration of these sorbents and how the carbon dioxide is removed so they can be reused.

Matthew Hunt is from Doosan Babcock, a Scottish-based company
spending a lot of effort in scaling up CCS technology, with demonstration plants in Canada. This is just a 4 tonne plant so far, which is no real use for a power plant which will need to porcess 850 tonnes of carbon dioxide a day, he said. But according to Hunt, the company is on track to full-scale post-combustion carbon dioxide removal by 2014.

Of course, the impetus for these small demonstration scale plants needs to come from government, and the feeling in certain quarters of this meeting at least, was that not enough push, and not enough decisiveness is being shown to make the technology viable.

My hope is that in 2014 we are not still at the stage where academics working in small groups are showing results of small scale CCS projects and saying that scale up is needed urgently.

Image: representation of MEA

Posted by Katharine Sanderson on August 05, 2009
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August 04, 2009

IUPAC '09: Livin' La Vida Loca

If you happen to swing by the Nature stand at the IUPAC congress exhibition, you'll have a rare treat. In the booth opposite is the stand for the next IUPAC congress, which will be in Puerto Rico in two year's time. 2011 is also going to be the International Year of Chemistry.

The stand there has on a loop a video of Puerto Rico's most famous (?) export Ricky Martin, as well as Marc Anthony (J. Lo's husband). This really is a rare treat in a chemistry conference, let me tell you.

Another treat is bumping into the congress chairman over a glass of wine at the poster session. Paul O'Brien from Manchester University seemed to be feeling the pressure of constant dinner engagements over the week. He said the whole experience made him nervous. From where I was standing listening to the gentle murmur of happy chemists I would say that any nerves were unfounded.

Posted by Katharine Sanderson on August 04, 2009
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IUPAC '09: Patenting bacteria

Chemists love to talk about the details of a synthetic reaction: swapping this carbon atom for that one, changing the angle between sulfur atoms by 2 degrees and so on. So during this morning's talk by Daniel Rabinovich from the University of North Carolina at Chapel Hill, I was happy to listen to him talking about tinkering with ligands to try and recreate the chemical environment that a copper atom finds itself in the small protein methanobactin thinking no more of it other than "chemists like to try and do this kind of thing".

Methanobactins are a small part of the large bacteria called methanotrophic bacteria that use methane to make their own carbon and energy. At their heart is a copper binding compound, which has fairly unusual chemical groups called thiones around it. As far as I could tell, the interest was in the synthetic challenge in recreating these unusual chemical group around the copper atom.

I mean, if chemists want to try and mimic nature's functions they tend to go after big things, like photosystem II, or a huge protein structure.

But I was wrong. It turns out that a patent was granted (to other scientists unrelated to this work) on the small copper-based protein methanobactin because it is a potent antibacterial agent against S. aureus, although this is a delicate protein that will be hard to recreate in its natural form.

Whilst trying to recreate the chemical geometry of the copper atom in this small delicate protein, Rabinovich actually found a way to make a synthetic version of an antibacterial, and that is what he's working on now.

Rabinovich has a better chance of making large amounts of the stuff. His work was all based on known procedures - albeit some obscure ones.

Posted by Katharine Sanderson on August 04, 2009
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August 03, 2009

IUPAC '09: Strontium sticks

On my way up to Glasgow from London I did a spot of sailing. On the trip from Fleetwood, Lancashire, to Whitehaven, Cumbria, for a long time we could see the nuclear fuel plant Sellafield. It spans a vast area of the Cumbrian coast line.

So it was with interest that I spotted a poster by PhD student Sarah Wallace from Leeds University in the UK.

She has been looking at how strontium, a waste product from Sellafield, will move in the sediment near the plant, and if it might make it into the groundwater.

The contaminant plumes from the plant tend to have a high pH, and what Wallace had found so far is that in these conditions strontium-90 likes to stick to sediment. This could actually be good news for Sellafield because the half life of strontium-90 is such that as long as it sticks to the ground it will have decayed within 300 years or so.

Strontium is potentially nasty because it's in the same chemical group as calcium, a major bone component. So if strontium gets into the water and into the body, it can compete with calcium in the bones and cause diseases such as leukemia.

Wallace's work involved a fake contaminated bit of land - taking normal soil and untouched groundwater from the area and spiking it. In future she hopes to see what the longer term effects of strontium-90 are.

Posted by Katharine Sanderson on August 03, 2009
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IUPAC '09: Mapping methanol in space

Who'd have thunk it - a chemistry conference full of space news. It's not that weird really, when you consider that the search for life = search for molecules.

Lars Kristensen from Leiden University in the Netherlands today showed us his maps of methanol in space. He is making these maps so he can see how methanol is distributed in the material that young stars are made from. Methanol is used as a tracer for early star formation and forms on the surface of interstellar ice-covered dust grains. He'll also soon be able to compare his methanol maps with results of water abundance from Herschel, which set off recently to check out the most distant objects in the universe.

Methanol forms as ice on dust grains. According to Kristensen, the major way that the methanol escapes from the surface of these grains is not by heating thermally, but by a non-thermal mechanism, be that activation by UV light, or other methods.

The abundance of methanol in the areas that Kristensen looked at, using the Harp B instrument on the James Clerk Maxwell Telescope in Hawaii, was constant throughout those areas, he says.

Check below the fold for one of his maps.

Continue reading "IUPAC '09: Mapping methanol in space" »

Posted by Katharine Sanderson on August 03, 2009
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IUPAC '09: Saving the planet one atom at a time

Hello from Glasgow, Scotland. Home to the deep fried mars bar, Charles Rennie Mackintosh, Gordon Brown MP, and now for one week only the IUPAC congress.

I'm here to delve into the finer points of chemistry and to see what is getting chemists salivating this year.

The first session I went to was about artificial photosynthesis. The process that plants carry out with ease - turning sunlight into stored energy - is causing a major headache for scientists trying to mimic the process.

Rather than try to rebuild the molecules used by nature for photosynthesis, chemists are looking at systems that they can build and understand better, and use them to do the same jobs that plants do with their complex molecular machinery.

In these systems, sunlight is used to power the separation of charge - from a neutral molecule to one with a positive and negative component. But the big problem is keeping those charged states apart from one another for any length of time. If they recombine, the charge separation, which could lead to electric current, is lost.

Today I got to see how making the molecules really long with the charged ends separate from each other in space can help. Ken Ghiggino from the University of Melbourne, Australia, uses a set of four porphyrins, which are big ring-shaped molecules. One end has a zinc atom sitting inside the ring and the other a gold atom. These two metals can shunt a charge from one end to the other. The trouble is that this kind of system is far too complicated to ever be manufactured on a large scale.

Another suggestion is simple dyad systems with one charge donating and one charge accepting part. But as Andy Benniston from Newcastle University showed us, to separate the charge with these systems is also not as easy as hoped. He suggested that when previous chemists have claimed to have a long lived charge separated state what they had actually done was form a different quantum state called a triplet state. This is something else entirely.

All this is yet more evidence that nature is unfathomably clever in its use of molecular processes to gain energy, and that humans are way behind in our understanding. But thanks to chemists who refuse to get depressed by this notion, one day we may just be able to take sunlight and produce energy that we can store and use at will, without destroying our world.

Posted by Katharine Sanderson on August 03, 2009
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