The next day, I saw a talk from Luisa de Cola, who makes really nice looking assemblies of zeolithes with alternating colors (very recently reported in Angewandte), and one from Lee Cronin who, presented the concept of iChell (hope Apple did not protect the name) as inorganic chemical cell, made of large polyoxometallate compounds.

Self-assembly of “green” zeolite crystals and "red” crystals leads to highly regular crystal chains with strictly alternating colors. (reproduced from Schulte, B., Tsotsalas, M., Becker, M., Studer, A. and De Cola, L. , Angew. Chem. Int. Ed. doi: 10.1002/anie.201002851)

Wednesday was also the day of the Congress Party, that took place in the VIP area of the football stadium (the easyCredit Stadion) with a big buffet and unlimited drinks, human table football games, and fireworks. That was quite a party, and a very good time… I hope they put some pics on the congress website soon!

The team from University of California (UC) Berkeley, and the Lawrence Berkeley National Laboratory, led by Carolyn Bertozzi, adapted the methodology known as ‘click-chemistry‘ to the particular conditions required by ‘in vivo’ conditions. Indeed, the original ‘click’ procedures, developed by Barry Sharpless (2), involved the use of toxic copper catalysts. In their article, the authors use a copper-free click reaction to label glycans – sugars particularly abundant on the surface of cells, where they are active in cell activity signalling, as well as in response to infections – which are thought of as appealing target for molecular imaging inside living organisms.

The first step involved the injection of azide-containing sugar derivatives, which are known to metabolically label glycans with the azide function. Then, a purposedly designed molecule carrying a signalling unit as well as a function reactive towards azides, had to be injected. The click reaction proceeded and as a result, glycans could be labeled in vivo, which paves the way for future specific biomolecule labeling inside living organisms.

Click chemistry inside a mouse (reproduced from ref. 1)

References:
(1) Pamela V. Chang, Jennifer A. Prescher, Ellen M. Sletten, Jeremy M. Baskin, Isaac A. Miller, Nicholas J. Agard,
Anderson Lo, and Carolyn R. Bertozzi, “Copper-free click chemistry in living animals”, Proc. Natl. Acad. Sci. USA, published online before print January 14, 2010. doi:10.1073/pnas.0911116107

(2) H. C. Kolb, M. G. Finn and K. B. Sharpless “Click Chemistry: Diverse Chemical Function from a Few Good Reactions”, Angew. Chem., Int. Ed. 2001, 40 2004–2021. doi:10.1002/1521-3773(20010601)40:11<2004::AID-ANIE2004>3.0.CO;2-5

In this context, lots of effort is dedicated to find ways to detect and destroy such compounds before they can cause harm. An appealing solution was recently proposed by a research team led by Julius Rebek, Jr. at the Scripps Institute. In an article recently published in Angewandte, they show how their novel molecules can signal the presence of organophosphorus compounds, but also render them harmless by undergoing a rapid reaction.

The sensing systems is based on an aromatic ring equipped with an oxime group (C=N-OH), which is known to react with organophosphorus compounds. The intermediate product instantaneously reacts further (which is important since at this point, the toxicity survives) to form a harmless decomposition compound and a fluorescent unit, which is used to signal the fact that the reaction has occured, and therefore the presence of toxic chemicals! Really smart approach!

References:
T. J. Dale, J. Rebek, Jr. Angew. Chem., Int. Ed. 2009, 48, 7850 –7852. DOI: 10.1002/anie.200902820

Press release: Ring Closure as Warning

Of course, I am not critisizing the recipients‘ work (anyway, I couldn’t since I am a chemist and don’t know lots of things about ribosomes, apart from their double-potato shape they always have in basic biology textbooks) nor the fact that it deserves recognition, but the point is that the Nobel prize in chemistry went to people who actually do chemistry, say, five times in the last 10 years (2000: conductive polymers, 2001: catalysis, 2002: mass spec and NMR, 2003: cell membranes, 2004: ubiquitin and protein degradation, 2005: metathesis, 2006: eukaryotic transcription, 2007: chemistry on surfaces, 2008: GFP and 2009: ribosomes). So, what about creating a Nobel Prize in biology? They did it for Economics in the 60s…

Well now we just have to wait for next year – and hope that people working with molecules lighter than 50 kDa will be recognized as chemists. I’m quite sure there are hosts of guys working in organic synthesis, catalysis, nanotechnology or physical chemistry – to mention a few – who deserve to get the next Nobels. And regarding Grätzel… I keep my celebrating post for next year!

Now, to be complete, I must mention that WolframAlpha comes with some limitations – or should I say, it is still being developed – but may well become an interesting alternative to other search engines. Among the limitations, if for example you enter ‘taxol’ in the query bar, you obtain a very approximate structure of the molecule, with no mention of stereochemistry, although it is of prime importance for this type of molecules. It also seems that the notion of ‘buffer’ does not (yet) exist, even though a ‘buffer calculator’ would be quite useful…

So have a look at WolframAlpha if you need simple information (on chemistry or whatever else btw) and also have a look at their blog, reporting their latest innovations and ideas.

A detailed study conducted at Appalachian State University in Boone, North Carolina, by Dr. Tonya S. Coffey, showed that, in addition to the candy roughness and porosity (they even made AFM study on Mentos candies !!), a second factor deeply influences the success or failure of a coke fountain: the surface tension of the liquid directly influences the bubbles formation rate, and a liquid containing an artificial sweetener (such as aspartam in diet coke) has a lower surface tension than a liquid containing a natural sugar. Furthermore, the gum arabic contained in mentos candies also brings a contribution to lowering the surface tension of the mixture.

It was also observed than, contrary to what is frequently postulated, no acid-base reaction is involved (actually, there is no base in a mentos candy, and the pH of the beverage does not change during the course of the ‘reaction’), the caffeine present in coke has hardly any influence on the result, contrary to the speed at which mentos candies sink into the liquid, which turns out to be of great importance!

In summary, the chemical geyser is due to the presence of a rough, porous ‘material’, in addition to chemicals that decrease the surface tension of the liquid, which contains dissolved carbon dioxide: these are the three basic ingredients of this funny recipe.

For more details:
T. S. Coffey, Am. J. Phys 2008, 76, 6, 551-557. DOI: 10.1119/1.2888546

Thanks Sophie for having suggested the topic of this post – btw, ideas always welcome!

Now researchers from University of Cambridge in UK and from University of Jyväskylä in Finland report in Science a tetrahedral cage-like molecule which can encapsulate tetrahedral molecules of white phosphorus. In addition of being ‘inactivated’, phosphorus was also rendered water soluble by encapsulation, and both forms, either solid or dissolved in water, were found to be literally indefinitely stable. Interestingly, the release of phosphorus from the cage can be controlled by addition of a competing guest (benzene) which expels phosphorus. Dr. Jonathan Nitschke, who led the research, underlines the potential applications of such container molecules (source: sciencedaily.com): “It is foreseeable that our technique might be used to clean up a white phosphorous spill, either as part of an industrial accident or in a war zone. In addition to its ability to inflict grievous harm while burning, white phosphorous is very toxic and poses a major environmental hazard.” In the future, this method can probably be adapted to target other harmful molecules.

For more information:
P. Mal, B. Breiner, K. Rissanen, J. R. Nitschke, Science 2009, 324, 1697. DOI: 10.1126/science.1175313

ScienceDaily, retrieved July 14, 2009.

Among the few ladies who presented talks during this symposium, the most amazing was the performance of Prof. H. Sleiman about incredible DNA assemblies. It is not exagerate to say the audience was stunned by the impressive pictures and videos displayed during this (super high-speed) presentation! In the same morning we had Nobel Prize Jean-Marie Lehn giving a philosophico-chemical lecture on adapative, almost darwinian, chemistry.

In the afternoon we attended a special session dedicated to six professors celebrating their 65th birthday in 2009. This session was chaired by the very funny Prof. H. Ringsdorf, who had great cartoons and quotes, but who also reminded the audience of the time when people were giving presentations with the help of transparencies and overhead projectors ! We then had presentations given by Profs Javier de Mendoza, Seiji Shinkai (who, as retired now, occupies simulataneously four different positions), Roeland Nolte (who found time to prepare a talk in spite of being main organiser of the whole conference), Julius Rebek (who fears to be killed by Barry Trost as his chemistry is highly non-atom-economical), Peter Tasker (who introduced us to the subject of extractive hydrometallurgy) and finally Jean-Pierre Sauvage (who is still considered as an inorganic chemist despite ligands syntheses involving more than 30 steps).

Prof JKM Sanders opened the next morning with a neat presentation, concluded by a very interesting advice: “expect, welcome and search carefully for the unexpected”! Prof S. Otto then explained why sometimes, chemistry requires to be “shaken, not stirred” and Prof. L. Cronin was the first people I ever saw who cited Kylie Minogue in a talk (he went too fast on it, unfortunately, I had no time to write the quote on my notebook). But his talk was quite impressive as well, dealing with huge systems obtained through self-assembly.

I finally must pay tribute to the great conference dinner we had… Dutch really know how to welcome guests (host-guest chemistry at its best…) and the result was a sparse audience in the next morning, as well as a lesser motivation in making notes… Remarkable was the talk given by K. Suzuki, a PhD student from Prof M. Fujita – and remarkable as well the possibility offered to a PhD student to present his work at this conference! And finally, after the presentation of Prof I. Goldberg, a discussion about the general question ‘what is it good for?’ a remarkable answer was given by Prof. Izatt, as another question: ‘What a new-born baby is good for?’ – I should remember this one for next time some friends of mine ask me why people do research…

In the opening address, it was mentioned that the meeting was initially planned to be held in Amsterdam, but, considering the ‘many potential distractions’, it was moved to Maastricht…

During the first session, Prof. S. Stupp mentioned how delighted he was of being ’surrounded by people who think supramolecular chemistry is interesting’, and Prof. E. Yashima showed us how to still manage a talk when a computer crashes right before. Then, Prof. M. Eddaoudi gave us an nice introdution on Molecular Organic Frameworks (also known as ‘MOFs’, a word to remember since it’ll came roughly every second talk of the conference) and MOMs (Molecular Organic Materials, a new acronym to me).

At the end of the session came the Izatt-Christensen Award ceremony, delivered to Prof. Omar Yaghi from UCLA. In his introduction, J. Fraser Stoddart mentioned that Yaghi and his work had been coined as “sucker for carbon dioxide” in the Los Angeles Time (the article can be read here)… After a series of congratulations came the lecture, a truly amazing presentation on MOFs, COFs and ZIFs, of which several thousands have been synthesised and characterised over last years (I definitely have to spend a post on Yaghi’s work sooner or later). Furthermore, many of these compounds were shown to be able of storing important gases such as CO₂ or methane. Explaining why it is so important to build complex artificial materials, Yaghi said beautifully that one ‘cannot build aeroplanes from proteins’.

After that, the opening buffet (not to mention a short walk on the empty town – sunday evening) concluded a very promising first day, and I’ll tell more about this conference in following posts – as well as how we ended up discussing the chirality of snails at a pizzeria table!

The element, which is roughly 277 times heavier than hydrogen, was produced by using a particle accelerator to fire zinc ions onto lead sheet: Zinc and lead atoms merge through nuclear fusion to produce Element 112: Zinc has the atomic number (hence the number of protons it contains) 30, lead has 82: when the new element is produced, all the protons are gathered in the newly formed nucleus.

The target wheel is equipped with thin lead foil. Inside the foil element 112 was produced for the first time after irradiation with zinc ions. (Credit: A. Zschau, GSI)

Element 112 is part of the so-called super heavy atoms, or transactinides: few is known about these elements, and they serve no purpose outside basic research. Their production requires heavy instrumentation (such as particle accelerators or nuclear reactors) and affords atomic-scale quantities, which, together with a fast radiactive decay (they are stable for a few minutes at best), make their study extremely complicated.

Update (14th July 2009): Prof. Hofmann and his team suggested the name of the new element to be Copernicium, with the symbol Cp. The final decision will be made by IUPAC within a few months. See the press release here.

More infos:

- press release from GSI (10.06.2009)
- Story as reported on ScienceDaily (12.06.2009)