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!

Today was the opening day, and thousands (really!) of chemists gathered in the huge congress center. The first -and only- talk I attended (due to a somewhat late arrival) was given by Prof. Klaus Müllen (from the Max Planck Institute for Polymer Research in Mainz). He quite impressively demonstrated how perfect graphene ribbons can be generated by bottom-up synthesis and subsequent reactions of benzene dendrimers (contrary to the method involving the peeling of graphite with tape). A very motivated and passionate speaker, he captivated his audience by showing amazing results, obtained by a careful design of a ‘core’ molecule, followed by its self-assembly into more complex structures.

This lecture was definitely a good start, and I’m looking forward to the next ones.

For more details:

Nature 2010, 466, 470-473 doi: 10.1038/nature09211

Advanced Materials, 2010. doi: 10.1002/adma.201001275

*I had to deal with my thesis writing & exam and some funding application stuff recently… and was close to an overdose of chemistry, hence my absence from the web.

Cloud whitening (SRM)

This concept, imagined by Stephan Salter from the University of Edinburgh, consists in spraying seawater in the atmosphere to increase reflectiveness of clouds. The clouds, produced by a fleet of around 1500 unmanned ships, would reflect more radiation from the earth. However, such an operation could have unexpected -and difficult to modelize- effects on oceanic climates and streams.

Covering the deserts with white films (SRM)

According to Alvia Gaskill who proposed this solution, covering a large enough area of the earth (first candidates would be Sahara, arabic and gobi deserts) could be expected to offset some or all of the projected additional radiative forcing and global warming from 2010 to 2070. Together with tremendous costs, ecological consequences such as perturbation of the atmospheric circulation (which could result in sub-saharian monsoon perturbation) must be feared.

Space sunshade (SRM)

Basically, this concept proposed by Roger Angel (University of Arizona), involves the use of trillions of small umbrellas, that would be put in orbit an stop some sunlight from reaching the Earth. If small 1 gram, 60 cm diameter discs were used, 800 000 of them would have to be sent every… minute, for 30 … years, in order to decrease the radiation hitting our planet of 1.8%.

Stratospheric sulfate aerosols (SRM)

Inspired by the eruption of Mount Pinatubo in 1991, which projected tons of particles in the atmosphere, and noticeably cooled the global temperatures of 0.5°C, chemistry Nobel Prize 1995 Paul J. Crutzen suggested the injection of sulfur compounds in the atmosphere. But this project could perturbate water cycles, the stratospheric ozone chemistry and biological life, which make large scale experimentation somewhat unrealistic.

Ocean iron fertilization (CDR)

This method involves the seeding of ocean with iron in order to promote a phytoplankton bloom, which can remove carbon dioxide from the atmosphere. Again, several side-effects are to be expected, as well as an increased water acidification, and the creation of large zones depleted from oxygen (the more the algae ‘breath’, the less oxygen available for the other species).

Although geoengineering is a flourishing field (just try to enter it in wikipedia), many of its promises will probably come true too late (if at all) if one wants to reduce anthropogenic global warming and climate change… scientific creativity will have to find other ways to deal with climate modifications.

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

Antonio Stradivari. Source: What We Hear in Music, Anne S. Faulkner, Victor Talking Machine Co., 1913.

A team led by Jean-Philippe Echard from the Laboratoire de recherche et restauration in the Musée de la Musique in Paris (an institution rarely found to contribute to Angewandte papers) recently published a study where investigations performed on 5 instruments that span 30 years of Stradivari’s career, are reported. They used complimentary analytical techniques to investigate the different varnish layers. To make the long story short, they found … nothing unusual or unexpected, but only materials broadly used in this time. The varnish is essentially made of two layers, the first (lower) one being used primarily to seal the wood and made of classical siccative oil. The second (upper) layer was found to caontain the same oil mixed with organic resins, and pigment particles. The latter were identified, and again, were found to belong to broadly used materials: inorganic salts (iron oxides, mercury sulfide) or organic crimson pigments.

Spanish Stradivarius II of c. 1687, on exhibit at Palacio Real de Madrid. Author H. Svensson

In conclusion, no trace of long hypothesized gums, amber or protein was found in any of the five instruments that have been investigated. Only common materials were used, and one must admit that the extraordinary quality of his instruments was (and still is) due to Stradivari’s exceptional talent as an intrument builder, but not to supernatural trick he may have used!

Reference: J.-P.Echard, L. Bertrand, A. von Bohlen, A.-S. Le Hô, C. Paris, L. Bellot-Gurlet, B. Soulier, A. Lattuati-Derieux, S. Thao, L. Robinet, B. Lavédrine, S. Vaiedelich, Angew. Chem., Int. Ed. published online. DOI: 10.1002/anie.200905131

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

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.

If you drive on the highway between Bern and Zurich, you will see at some point (in Kölliken) a huge metallic, white structure somewhat looking like one of these artificial ski resorts which have been flourishing here and there around the world. However what this gigantic cage contains is not snow, but roughly 550 000 tons (!) of waste, mostly toxic chemicals, stored here completely unlabeled, unclassified and without any kind of precaution. Among others, drums with production residues from the chemical industry, electroplating sludges, phosphoric waste, oil contaminated soil, or bag containing unsorted loose waste were delivered to the landfill. In 1985, foul smells and strangely-colored dusts lead to the dump to be closed – at that time, this meant the waste was covered by around 10 meters earth… It was then observed that underground water was becoming polluted, threatening the drinking water. The authorities finally decided the site had to be decontaminated and the waste properly treated.

An impressive draining system was build to prevent water flowing under the contaminated area from polluting further ground water. Then the huge building (of a total surface equivalent to that of ten football pitches) covering the whole area was built, and kept under slightly reduced pressure such as to prevent any escape of dust, gas or odors. The access to the main building is severely restricted, and one can enter only fully equipped with airtight suit and oxygen supply. There, samples are prelevated from rust covered tanks to try and identify what had been buried 25 years ago. The waste are then separated and sent for proper treatment. This goes not without any risk, since in summer 2008 a violent fire suddenly broke out, due to fortuitous contact between magnesium and air moisture…

A view of the inside of the main building.

This is shown in this impressive video recorded by safety cameras (in Swiss-German, but the images really show how ruined the place is, and what are the working conditions. Another video (in French) can be found here telling about the landfill.

If everything goes as planned, the waste evacuation should last until 2012, and the area should ‘look like before’ in 2015. The cost of the whole operation will likely reach 1 billion swiss francs (ca. 965 millions US$) – a good sum just to repare mistakes from the past. The good news is that is was acknowledged at some point that these mistakes were putting populations and environment at risk, and appropriate arrangements were made in order to fix the situation, whatever the costs were to be. There are some lessons to take home there!

For more informations

The society responsible for the decontamination of the landfill: SMDK (in German)

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…