The importance of rare earth elements is less obvious that that of more common resources – we don’t eat them nor power our cars with them. However, their use in many of recent high-tech innovations make them an invaluable resource for the decades to come: computer hard drives contain neodymium and dysprosium, tellurium is used in solar cells, and several rare earth elements are so far irreplacable in optical devices such as lasers, LEDs and phosphors. Although rare earths are not so scarce, their distribution on earth is uneven – and more than 90% are currently produced in China. The US and other countries consider (re)opening mining sites, but for the upcoming years, China will have an increasing weight and decision power over prices and distribution of rare earths.

In order to ensure a sustainable use of scarce elements, strong incentives will be needed. For example in Japan, a country without such resources which industry highly depends on importation, the Element Strategy Initiative is a good example of such efforts.[2] Besides reuse and recycling, the potential lack of such elements can be regarded as another challenge for researchers worldwide, who are trying to find alternative materials, thus reducing the need for rare earths in the future.[3]

More generally, the rare earth issue reflects a more general problem that may occur in the upcoming decades: I remember a seminar where a professor mentioned that, if the current trends go on, we will be running out of most precious metals (e.g., rhodium, platinum) in less than a hundred years. Further, resources of lithium (for rechargeable batteries) and phosphorous (for fertilizers) are also limited. In every single field, from ’simple’ food production to state-of-the-art technologies, the limited resources of our planet will eventually constrain us to play the equilibrist’s game of long-term sustainability.

References:

[1] Nature Materials 2011, 10, 157. DOI: 10.1038/nmat2985
[2] Nature Materials 2011, 10, 158. DOI: 10.1038/nmat2969
[3] Nature Materials 2011, 10, 162. DOI: 10.1038/nmat2973

See also:

Nature Photonics 2011, 5, 1. DOI: 10.1038/nphoton.2010.308

The compound has been known for decades to mimic the effects of estrogen in the body. Hence, particular concerns have been raised regarding the absorption of BPA by pregnant women and babies. Particularly, it was suggested that BPA-containing baby bottles should be avoided, since they are extremely likely to leach BPA in baby drinks. Further, BPA was related to illnesses such as obesity, heart disease, cancer, diabetes, fertility problems, and birth defects.

So far, Canada and Australia have been the first countries to classify BPA as toxic (despite recriminations from the chemical industry), and France and Denmark had already banned BPA from baby bottles. On 25 November, 2010, the European Union executive commission decided to ban production, and commercialization, of polycarbonate-based baby bottles containing bisphenol A. The new regulations will be enforced during the first semester of 2011.

However, some criticize the decision, calling it more political than based on sound science, and not every country is ready to ban BPA. In Swizerland, where we usually like to do things differently, the Federal Office of Public Health considers BPA as non-harmful for consumers, since only high doses are known to be problematic. According to them, a ban on BPA would lead manufacturers to employ other, lesser known compounds, which toxicity is still unknown.

Then, is a ban on BPA an over-reaction or a wise precaution? Only the future (and more experiments) will tell.

Further reading:

http://www.nature.com/news/2010/101104/full/news.2010.581.html

On the live webcast visible on the Nobelprize website, the Prize announcement was followed by a live phone interview with Prof. Negishi. He let the audience know he was awaken at 5 in the morning by the phone call announcing him the good news, and that he just had time for a coffee before the interview took place. I imagine this was but the beginning of a very long day for him! Quite amusing was when a journalist asked Negishi about the impact of his discoveries for the human beings. At that, Negishi responded something like ‘Do you have any knowledge of Grignard chemistry?’ The journalist laughed before admitting that he had no clue about it, and Negishi explained the impact of carbon cross couplings in much simpler terms.

* Andre Geim is probably the first researcher to detain a Nobel Prize together with a Ig Nobel Prize, obtained in 2000 for levitating a frog with magnets.

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!

In my imagination, conferences in the past involved a passionate speaker (usually wearing a hat) who was disclosing his/her latest discoveries, vehemently speaking or writing on a blackboard (sometimes performing live experiments) while the audience was listening in a profound, respectful silence.

Today, what I saw was somewhat different – and I’m not talking of speakers not wearing hats. Actually, I was at a presentation seating next to a professor, who was preparing the powerpoint he was going to present in the afternoon. To do this, he had to ask his collaborator, seated next to him, about the meaning of some graphs he intended to include in the presentation. This took approximately one hour, and was quite disturbing to all the people around, since the discussion included mumblings and laughters.

So, without even considering half of the members of the audience who checked their e-mails or the news on CNN every 5 minutes on their iPhone, I was wondering whether the speaker was noticing this lack of attention. The answer I guessed is probably no (because speakers are generally too busy and stressed to notice what happens behind the front row) but still, I’m wondering why people go to talks to prepare their own slides??

Besides, I wanted to mention today’s plenary session, where Prof. Michael Grätzel from EPFL (it’s always funny to go abroad to attend talks from our own faculty) presented the latest advances in dye sensitized solar cells (DSCs). I still hope to write a full post about Prof. Grätzel’s work sometimes (like next October 6th), and here I just want to mention that there is now a Michael Grätzel Center in Wuhan (China) which, I think, is quite something. The optimism and enthusiasm of Prof. Grätzel are always extraordinarily communicative (especially when it comes to recent applications), and I’m deeply convinced that the future is bright for dye-sensitized solar cells

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.

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

It is well known that the ‘usual’ green colour is due to the presence of chlorophyll in the leaves, which harvest red and blue light to fuel photosynthetic reactions. In turn, photosynthesis allows the plant to produce carbohydrates (sugars) to sustain growth and development, together with converting carbon dioxide into oxygen. When temperatures start to decrease, and days to shorten, the amount of chlorophyll in the leaves slowly decays. Indeed, warm temperatures are required for the plant to replace the chlorophyll which is gradually decomposed over time. As the concentration of chlorophyll decreases, other dye molecules present in the leaves become more and more visible. These are essentially carotene (which gives carrots their colour) and anthocyanins (present in red grapes and wine). Depending on the tree, and on the weather conditions, the leaves become yellow or more red-brown as the green colour fades, giving rise to awesome landscapes. I spent some holiday in Japan just one year ago, and the weather forecast during this period includes very detailed maps showing the ‘red leaves forecast’!

Autumn colors in Japan, here in Shirakawa-go....

... and in Nikko.

And here are some of the molecules responsible for these various and impressive color changes:

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!