Category: Chemistry

The Q4 issue of the Cutting Edge of Chemistry (PDF) newsletter which I produce for ThomsonReuters is now online. In this latest issue:

Organic synthesis scheme showcase – The nutlins were first identified by scientists screening a chemical library at Hoffmann-La Roche. In this article, we showcase a new synthetic route to (-)-nutlin 3 recently developed by Tyler Davis and Jeffrey Johnston of Vanderbilt University, that paves the way into the enantioselective arena of nutlin synthesis.

Scaffolds on the move – A wide range of new skeletons emphasize that novel chemical scaffolds with biological activity underpin major advances in medicinal chemistry.

New molecular modes of action – New molecular mechanisms of action are disclosed for a variety of indications.

The starting line – This issue includes drugs related to diabetes, cancer and other conditions such as Graves’ disease and multiple sclerosis.

Downsizing pharma and upgrading collaborations – In this report, we look at how the downsizing pharmaceutical industry is generating new opportunities for the smaller biotechnology and discovery companies. Collaborations between large pharma companies and these smaller enterprises, and even university departments and their spin-off companies, can help cut the overall risk exposure as well as lower investment costs significantly through a focus on developing only those drugs emerging from small laboratories that already show a great deal of clinical promise.

If you enjoyed the newsletter, you might also like my report commemorating the 2011 International Year of Chemistry, entitled “The Changing Role of Chemistry in Drug Discovery“, also available as a free PDF download. The report explores the current state of the pharma and reports the views of several key pharmaceutical industry players, examining how life in drug discovery has changed and how it will continue to change and adapt in the future.

It is a perennial on almost every chemistry course: the Haber-Bosch process for making ammonia. A potassium-doped iron catalyst is heated to several hundred degrees and high pressure nitrogen and hydrogen gas mixed over it to generate ammonia, which is then fed into fertiliser production. The H-B process very effectively traps and fixes nitrogen from the air, and is the industrial equivalent of nitrogen fixation by legumes and living other plants. The process, first demonstrated in 1909, has fed millions of people through the agricultural revolution of the twentieth century. You might say it has allowed our species to become so successful that it now numbers 7 billion…

However, that high temperature, even taking into account the industrial chemical engineer’s need for good quality “waste” heat for distillation towers and the like, is still wasteful. Catalysts that operate at a much lower temperature would be useful. It would also be useful if they could be dissolved rather than being solids, that would improve efficiency considerably given that the bottleneck in the H-B process is the release of nitrogen from the catalyst surface.

I just covered research from Patrick Holland and colleagues at the University of Rochester, New York, USA and the Max-Planck-Institut für Bioanorganische in Mülheim an der Ruhr, Germany, who have developed an iron compound that can promote the H-B process. You can read my full report on the research this week in Chemistry World.

Holland told me a bit more about his hopes for the research:

“I can envision two possibilities [in enhancing the energy efficiency of the H-B process],” he told me. “First, the structural information from our compounds could be used to design new solid surfaces for the H-B catalyst. In this way, we help surface scientists to formulate useful targets for the synthesis of solid catalysts. Secondly, if we could ultimately tune our solution complexes to make a catalyst that turns over many times in solution at room temperature, then it would reduce the high temperatures and pressures that are currently needed in the H-B process.”

I was curious as to what benefits such a catalyst might have over the standard catalysts that have been used and optimised over the last 100 years. “The high temperatures and pressures used in the H-B process place severe requirements on the factory,” Holland added, “after all, they use high-pressure hydrogen at hundreds of degrees Celsius! It is interesting to consider the reasons for these extreme conditions. The H-B process has a delta-G near zero, so the process is thermodynamically feasible but the rate of catalysis is slow. The reason it must be heated is to give an acceptable rate. Because the Haber-Bosch process is entropically unfavourable, the equilibrium becomes unfavourable at a high temperature unless the pressure is raised. So, the only reason for the high pressure is the high temperature that is needed for catalysis! A faster catalyst would work at lower temperatures, and require lower pressures too.”

There are several obstacles to surmount before a new low-temperature catalyst is ever available for ammonia production. “The current obstacles are that we need to make the final hydride product bind dinitrogen to ‘turn over’ [catalytically speaking] and secondly we need to increase the yields of the nitrogen and hydrogen reactions,” Holland told me. He adds that, “We have other related hydride complexes that can be converted into dinitrogen complexes, and so the situation is hopeful with respect to the first point. We are optimistic that by tuning the supporting ligands we can solve both of these problems and converge on a catalytic system.”

Meghan M. Rodriguez, Eckhard Bill, William W. Brennessel, Patrick L. Holland (2011). N2 Reduction and Hydrogenation to Ammonia by a Molecular Iron-Potassium Complex Science, 334, 780-783 : 10.1126/science.1211906

I recently wrote about how Raman spectroscopy could change the way forensic scientists analyse splashes and stains during a crime scene investigation or a suspect’s clothes and skin. Last year, it was saliva analysis, most recently the research has focused on female bodily fluids associated with the scene of a sexual assault or rape. The work is that of Igor Lednev’s team at University at Albany, SUNY, New York. They have now added near-infrared Raman microspectroscopy and an advanced statistical analysis to the arsenal of techniques available to law enforcement scientists allowing them to quickly and accurately identify traces of vaginal fluid at a crime scene, on suspect clothing or skin.

Team member created several montages to illustrate my article, but obviously there was not space for all of them in the published version, so I am reproducing them here. They’re very, very good.

Sikirzhytskaya, A., Sikirzhytski, V., & Lednev, I. (2011). Raman spectroscopic signature of vaginal fluid and its potential application in forensic body fluid identification Forensic Science International DOI: 10.1016/j.forsciint.2011.08.015

The Royal Swedish Academy of Sciences has decided to award the Nobel Prize in Chemistry for 2011 to Daniel Shechtman
Technion – Israel Institute of Technology, Haifa, Israel “for the discovery of quasicrystals”

I got my tweet out seconds before NobelPrize_org and certainly before the rest of the chemistry blogosphere. Sad or what?

In quasicrystals, we find the fascinating mosaics of the Arabic world (see my Alhambra photos for examples) reproduced at the level of atoms: regular patterns that never repeat themselves. However, the configuration found in quasicrystals was considered impossible, and Daniel Shechtman had to fight a fierce battle against established science. The Nobel Prize in Chemistry 2011 has fundamentally altered how chemists conceive of solid matter.

Full Nobel Chemistry press release here.

UPDATE: Shechtman is 70 years old and his work is one of the first times we can date a Nobel-winning scientific discovery to a specific day in 1982. Committee is hoping to speak to him by phone, but they cannot get hold of him right now.

Quasicrystal patterns that are infinite and do not fit the normal requirements of regular solid, crystal structure, has revolutionised our view of solid matter over the years. It shook the foundations of solid-state science. The discovery has actually left us knowing less than we knew before the discovery. It changed the concept of crystallinity. We now do not know what constitutes a crystal. Indeed, we only have an operational definition now the defines a crystal as a solid that produces a diffraction pattern under X-ray irradiation. Regularity no longer comes into it. (To paraphrase committee member Sven Lidin).

UPDATE: Just had word from Professor David Phillips, President of the Royal Society of Chemistry: “Quasicrystals are a fascinating aspect of chemical and material science — crystals that break all the rules of being a crystal at all!” he says. “They’re quite beautiful, and have potential applications in protective alloys and coatings. The award of the Nobel Prize to Dany Shechtman is a celebration of fundamental research.”

The Case of the Sulphuric Acid plant was an educational short movie from 1976 aimed at schools and has as its narrator, Monty Python cast member John Cleese, who also features in animated form thanks to the late, great Tony Hart (of Vision On, Take Hart fame). The movie clip was posted on Youtube by the Royal Society of Chemistry recently after a long-lost reel was tracked down by Eton College and with the permission of ccopyrihht holder Akzo Nobel with legal lubrication by Wendy Warr, apparently. As the title would suggest it tells the tale of a sulfuric acid plant (current IUPAC spelling has f not ph, by the way).

Yes, sadly, I am old enough to recall seeing this short movie in school some time in the 1970s (I would have still been in junior school when it was first released, so I suspect it was shown in high school in the late 1970s, just for the record).

This video was viewed 809 times 4th August 2011, 1740 by 10th September. 3415 as of 31st January 2012.

Scerri stuff indeed – Non-chemists, and perhaps a few chemists, might have assumed that once all the holes in Mendeleev's Periodic Table were filled with modern discoveries and the lanthanides and actinides added, that the Table was forever immutable, a stone tablet to adorn high school chemistry lab walls, textbooks and websites unchanged forever more…well they'd be wrong, some chemists think it's time for a change.