The Mysterious X

Chemistry World blog (RSC) - 14 May, 2015 - 17:43

Guest post by Rowena Fletcher-Wood

The x-ray has always been a mysterious thing. An invisible beam of high energy electromagnetic radiation that passes through most kinds of matter, it is even named ‘x’ after the mathematical variable used to denote the unknown. And the x-ray itself isn’t the only unknown thing – so are its origins. Sources suggest it was an accidental discovery, but there aren’t as many sources as there should be, due to a very non-accidental fire.

Wilhelm Röntgen, German physicist and discoverer of x-rays, died on 10 February 1923, whereupon all his laboratory records were burnt on his request.

It was an extreme action, but not an unusual one.

While modern science is becoming more and more transparent, not very long ago secrecy was the tool of the inventor’s trade. Through secrecy, successful men were able to preserve their impression of genius, compete against their peers and prevent their ideas from being stolen. The most coveted prize was not scientific elucidation but personal recognition – impossible for those who were too open and lost their ideas to the less scrupulous. It wasn’t just seen amongst scientists; William Howson Taylor, founder of the admired Ruskin pottery, had all his notes burnt at his death in 1935. And so the method was lost with its maker.

We are left with a fuzzy picture, not much easier to illuminate than x-rays themselves, and can only imagine the scene in Röntgen’s laboratory in the winter of 1895…

A dark room, because Röntgen was working with light.

A screen coated with barium platinocyanide.

On the bench top nine feet away, a Crookes cathode-ray tube, a large glass gas-filled bulb that fluoresces when a high-voltage electrical current is discharged through it. But the bulb is not visible, because Röntgen has covered it with thick black cardboard to contain the distracting glow (and because it’s currently switched off.)

Then Röntgen turns on the tube and the screen begins to glow green…

Nine feet was further than the reach of the blocked cathode rays that Röntgen understood, and he quickly concluded that he had made a new, unknown kind of ray that could travel through cardboard. He tried it with aluminium, copper and brick – it travelled through all of those too. In fact, the only material he found that could absorb it was thick lead.

So naturally, he did what any discerning 19th century scientist would do in his position: he stuck his hand in it. On the screen, he could see the image of his own bones, surrounded by a greenish glowing flesh. He seized some photographic film, and took the first x-ray image. When he repeated the procedure to photograph his wife’s hand and rings for his publication on a ‘new kind of rays’, she famously cried, ‘I have seen my own death!’

100 years later, medical physicist Gerrit Kemerink of the Maastricht University Medical Center thought to piece together some of the missing evidence, and recreated the setup of some of the very first x-ray machines. With a hand he borrowed from medical supplies, he set up the experiment just as Röntgen might have done, and tested the results. Horrifyingly, he found that the hand needed a full 90 minutes of exposure to create a clear image, providing a radiation dose 1500 times more than the dose supplied by a modern x-ray procedure. No wonder early x-ray testers reported burns and hair loss!

Modern x-ray production methods also help us understand what was going on in Röntgen’s Crookes tube: he used a hot cathode to produce electrons, which were then accelerated under a voltage, striking a metal target and knocking off more electrons. Not only were electrons emitted, but the metal was left full of electron vacancies, holes from where the AWOL electrons had been knocked. X-rays are emitted when high energy electrons shift into lower energy vacancies, and so the energy of the x-ray is specific to the metal they came from. Today, copper anode metals are mostly used, but Röntgen probably produced x-rays by ionising the gas inside his tube. If so, he would have produced lower energy x-rays and so required the longer measuring times.

Röntgen may have burned the notes and reports, preventing us from ever understanding the precise details of his experiments, but he did publish three papers on these mysterious new rays, and left us with an invaluable scientific and medical tool.

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Categories: Education

Lego chemical constructions

Chemistry World blog (RSC) - 7 May, 2015 - 16:17

Guest post from Tom Branson

The famous Lego bricks have invaded almost all walks of life. Not content to remain as just a construction-themed toy, Lego has branched out into theme parks, video games, board games, clothing lines and even a movie. Until recently, however, chemistry remained a relatively unbuilt area. This changed last year with the production of an all female Lego academics lab, which was met by Lego and science fans alike screaming ‘just take my money!’ The set featured an archaeologist, an astronomer and a chemist and was not only super fun but helped to promote women in science. The plastic academic trio shot to stardom with their Twitter account showcasing some of the finer moments of life in the lab. Now, Lego has finally found a place at the pinnacle of scientific achievement on the front cover of the latest issue of Chemical Science.

A Lego chemist on the cover is dashing back into the lab carrying a flask ready for her next experiment. She is already wearing her white coat, blue gloves and glasses showing that even minifigures are safety conscious. Like many lab users she has made good use of the wall space by drawing out her chemical reactions. Although, the lab does seem rather open to the elements with the sun, clouds and rain threatening to ruin or in fact perhaps aid the artificial photosynthesis project taking place.

Lego is an awesome tool for building miniature skyscrapers and racing cars. So why not use it to build miniature or, more realistically, gigantic chemical structures? I think the authors could have used a little more creativity with the Lego for this cover – surely it’s not that difficult to build their cobalt complex out of the little bricks? Excuse me at this point whilst I run up to the attic, dive into my childhood supply and attempt to create a chemical masterpiece…

…actually it is quite difficult after all! Lego may seem like a nice alternative to the old ball and stick modelling kit, but it is not quite so specialised just yet.

The research performed by the group of Erwin Reisner, from the University of Cambridge, tells of their latest work on the development of a cobalt catalyst for H2 evolution. The metal complex they created shows good stability when anchored onto a metal oxide surface and also enhanced activity compared to previously reported cobalt catalysts. For a closer look into how the catalyst was built step by step (or perhaps brick by brick) head over to Chemical Science.

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April 2015: Writing Science

Royal Society R.Science - 1 May, 2015 - 13:10

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The great chemical hunt

Chemistry World blog (RSC) - 23 April, 2015 - 12:29

Guest post by Heather Cassell

When starting a new experiment, it is great if there is a standard lab protocol (written by someone else in the lab) that you can use. These tried and tested methods usually increase the chance of your experiment working. On receiving the new protocol, the first thing you need to do is read the method carefully so you can plan accordingly; I’ve been caught out before – I found out part way through what I thought was a two hour incubation that it was really 12 hours, so I ended up having to finish off the experiment on Saturday!

Shelf of chemical bottles

— © Shutterstock

The next thing is to check that all the equipment and chemicals you need are in the lab (and in large enough quantities), especially if the protocol is not used often. This allows you to book the equipment if necessary, and means you don’t have to run round trying to find things once you have started. Finding the equipment is relatively easy: it tends to be quite big, and people generally don’t walk off with it without asking; chemicals, on the other hand, can be stored in many different locations around the lab depending on their properties, and occasionally people will put them back in the wrong place.

There are different ways you can approach finding the chemicals you need: you can check the lab’s chemical list (if one exists) to see if there is any and where it is stored; you can ask someone in the lab; you can look up the properties of the chemical to give you an idea of where to look; or you can try and find it yourself using only the name. This last method usually starts with ‘I’ll just have a quick look to see if we have any, it shouldn’t take long’, and often end ups being a great chemical hunt that takes ages.

The first stop on the search is usually the room-temperature chemicals, as there are more of these. They can be split up into communal stores and specific groups’ (or even individuals’) chemicals, and tend to be kept in store cupboards or on shelves around the lab. When venturing into other groups’ stores, be sure to ask permission before you take anything. If this search is fruitless then there are the specialised chemical cabinets (flammables, halogens, poisons) to check, the fridges and freezers (again both communal and individual lab group ones), and finally the deep freeze (–80oC), though not many chemicals are stored there.

If – after searching all these places and exhausting the other methods – you still can’t find what you’re looking for, you’ll have to order it fresh. Sometimes, after putting in the order, someone will point out that the chemical is in some place that you didn’t search, or you’ll stumble across it by accident. But at least next time you know where to find it – well, hopefully you will anyway!


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Where there’s sludge there’s, um, ferrocene?

Chemistry World blog (RSC) - 9 April, 2015 - 17:26

Guest post by Rowena Fletcher-Wood

Nobody had thought to study the orange sludge that was scraped off the Union Carbide pipes after manufacturing cyclopentadiene, but perhaps they should have done. When chemists eventually set their gaze on this colourful by product, the ensuing discovery of ferrocene catalysed a branch of research.

Organometallics had proved themselves a hard puzzle to crack, with only a handful developed by the 1950s, including the infamous Grignard reagents. Iron organometallics remained elusive, which is why Thomas Kealy and Peter Pauson, working at Duquesne University in 1951, had no intention of synthesising any. In fact, they were trying to make a totally organic compound: pentafulvalene, a molecule built from two cyclopentadiene rings fused together by a double bond. Samuel Miller, John Tebboth and John Tremaine, chemists at the British Oxygen Company, demonstrated no more interest in organometallics: their aim was to develop a new method of preparing amides from nitrogen and hydrocarbons, including cyclopentadiene. Both threw in iron catalysts – after all, iron was not going to form stable organometallic compounds, was it?

Yes it was. And this time when the orange sludge was produced, the groups did decide to study it, if only because they thought they might have made their target compounds. The composition – C10H10­Fe – proved them both to be wrong.

But what was this new molecule? Whatever it was, it was soluble in all organic solvents, but not in water, and unaffected by 10% NaOH and concentrated HCl, even after boiling. In fact, it remained stable up to 400°C, melting at 173ºC without entertaining the risk of decomposition. The two reports were published in Nature and the Journal of the Chemical Society respectively, with the proposed structure of two cyclopentadiene rings joined by a single bond bisected by Fe2+. That might have been that, if it were not for the amazing power of doubt in driving the advance of research…

In the chemistry department of Harvard University, Robert Burns Woodward was perusing the literature when he came across the Kealy and Pauson paper. He didn’t like it: something niggled at him. So he set his graduate student, Myron Rosenblum, the task of repeating and expanding on the work with the help of Geoffrey Wilkinson. IR and NMR data soon indicated identical ionic-covalent bonding across all of the carbon atoms, and Woodward and Wilkinson formulated the true ferrocene structure: one iron atom sandwiched between two misaligned, flat aromatic pentagons. At the Technische Hochschule, Munich, Ernst Otto Fischer produced x-ray crystallographic images of ferrocene, which led him to the same conclusion. It was a brave first step into a bizarre unknown territory: no such structures had been known before – but soon they would.

With the pioneering concept of aromatic-metal π-bonding and the overhaul of classical ligand theories, organometallics exploded onto the chemical scene. Between them, Woodward, Wilkinson, Fischer and others produced a cascade of new molecules with novel functions, delving deep into d-block chemistry, Friedel-Crafts acylation and other aromatic substitutions. Today, metallocenes have found applications ranging from antiknocking fuel additives to syndioselective polymerisation catalysts and charge-carrying components in diabetic blood sugar monitors.

But what really tops off this story is its shining example of conscientious peer review. All too often, scientists don’t repeat each others’ work. Whether they are demotivated by lack of equipment, resources, time or comprehensible instructions, without repetitions, there is no real way to falsify new findings or shift the paradigms of existing understanding in the light of new discoveries. Indeed, the preparation and characterisation of ferrocene wouldn’t have been repeated if the chemical community hadn’t been so shocked by the discovery. It was hard to believe such a lucky windfall. Amongst others, Oxford crystallographer Jack Dunitz was so unconvinced that he and colleague Leslie Orgel repeated the whole thing once again and proved it to be – correct. ‘There was no doubt about it,’ Dunitz confirmed. Sometimes glorious accidents happen, but often a sludge is, after all, just a sludge.

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Academic family: Fritz Haber

Chemistry World blog (RSC) - 9 April, 2015 - 12:23

Guest post by JessTheChemist

’The field of scientific abstraction encompasses independent kingdoms of ideas and of experiments and within these, rulers whose fame outlasts the centuries. But they are not the only kings in science. He also is a king who guides the spirit of his contemporaries by knowledge and creative work, by teaching and research in the field of applied science, and who conquers for science provinces which have only been raided by craftsmen.’ – Fritz Haber

This month marks the one hundred year anniversary of the first use of chemical warfare as a strategic tool in battle. Fritz Haber was heavily involved in, and a proponent of, gassing with chlorine as a method of warfare. Whilst his work in this area may have resulted in huge loss of life, he also changed the world for the better through the discovery of the Haber-Bosch process.

The Haber-Bosch process, named after Fritz Haber and Carl Bosch, was one of the first industrial chemical processes that I learned about at high school. At the time, I found it incredibly interesting that some pressure and some heat, with some iron thrown in for good measure, could turn nitrogen gas and hydrogen gas into malodourous ammonia. The reaction had been known before but the low yields and slow reaction times made it an unattractive prospect for an industrial process. Haber realised that the addition of high temperature and pressure with an iron catalyst could make this a highly efficient process. Haber won the Nobel prize in chemistry in 1918 for his identification of the process, while Bosch won the prize in 1931 for his work in scaling up the process.

With cheap access to ammonia, fertilizers were became more readily available and, as such, millions of people around the world benefit from the availability of good quality crops. But the availability of ammonia also led to an proliferation in the use of nitrate-based explosives, as Wilhelm Ostwald discovered that ammonia could be converted relatively simply into nitric acid and nitrates using a platinum catalyst (the Ostwald Process).

Haber’s father owned a dye pigments and paints business, so it is not a surprise that he entered into the field of chemistry. After attending university, a brief period working for his father and various apprenticeships, he took up an academic position at the University of Karlsruhe.

As with the other laureates I’ve researched on this blog, Haber is connected to a number of highly influential scientists, including Walther Nernst, his closest academic relative,. Nernst helped to develop the modern field of physical chemistry, including electrochemistry and thermodynamics. All undergraduate chemists should recognise his name from learning all about the Nernst equation! He won the Nobel prize in chemistry in 1920 for his work into thermochemistry. Through Nernst, Haber is also connected to Irving Langmuir who won the Nobel prize in 1932 for his research on surface chemistry.

Haber is related to Adolf von Baeyer, an organic chemist who is famous for the synthesis of indigo. In 1905 he was awarded the Nobel prize in chemistry for his research in the field of organic chemistry, particularly organic dyes and hydroaromatic compounds. There is also an academic connection between Haber and Bosch, although they worked independently from one another on the same chemical process. Once Haber had developed the Haber process, it was purchased by the German chemical company BASF, where Carl Bosch managed to scale up the reaction to the industrial level, resulting in the Haber-Bosch process.

Whether you believe Fritz Haber is a great man or not, it cannot be said that his (and Bosch’s) finding was not a great one.

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Categories: Education

Take 1 minute…for your last chance to vote!

Chemistry World blog (RSC) - 8 April, 2015 - 11:33

Guest post from Holly Salisbury

There’s just one week left to vote for your favourite Take 1… minute for chemistry in health video.

The shortlisted videos are online for one more week – this is your last chance to pick your favourite to win the £500 cash prize!

The chemical sciences play a fundamental role in improving healthcare. We invited undergraduates through to early career researchers to produce an original video that communicated how chemistry helps us address healthcare challenges in an imaginative way. The videos show the use of nanoparticles for drug delivery through to the development of antifreezes useful for long-term blood and organ storage. Others explain the chemistry of fat cells, illustrate the chemistry of toothpaste, and highlight the impact of chemistry in treating cancer and tackling antibiotic resistance.

Want to get involved? Watch our 6 shortlisted videos (below) and vote for your favourite before 11.59pm (GMT) 17 April 2015!

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Categories: Education

I may not know what’s happening, but I want to find out

Chemistry World blog (RSC) - 2 April, 2015 - 14:39

Guest post from Tom Branson

I have tried many different ways to make chemistry make visual sense. I have struggled to make the π orbitals overlap in a Diels-Alder reaction scheme. I have toiled away building cardboard proteins to model a complex. And I still draw little cartoon viruses at work today. We cannot see exactly what goes on when proteins bump into each other or when electrons are shared between atoms, but we can attempt to visualise these natural phenomena in the best way possible. Making this both easy to understand and scientifically accurate, however, is not a simple task.

Chemical reactions and molecular interactions can be displayed in countless different ways. On the front and inside front cover of this month’s Chemical Science are two such attempts to show what is really going on in the reaction flask. The front cover is a drawing of a virus opening up, spitting out a big purple helicase protein that winds its way along a ‘tongue’ of DNA. An iridium complex sits nearby on the shelf of a G-quadruplex, illuminating the surrounding cell quagmire as it searches out the viral helicase. A sketch like this (and this is quite a nice example) is an accessible but basic way of explaining these kinds of biological events. It works to some extent: you get the idea – the main players in the game – but it’s not easy to grasp exactly what’s going on. The question now is: do you want to know what’s going on? For me, there seems to be something lacking. Everything is too static, it needs some excitement, some energy.

On the inside front cover, however, is a bright, shiny and dynamic computer model of two norbornenes crashing into each other. The molecules seem to have been caught at the very moment they touch and their physical forms fall apart. The disintegration as they approach allows for them to be rebuilt into their new, combined structure. The trail of successfully connected rings stretching off into the distance gives us a sense of time – reassuring us that the future is predictable and that everything is going to be alright – but here, in the present, there is the threat of annihilation before these bonds are fully formed. Now, this is cool. I’ve never seen a reaction posed in such a way. From the image you can’t tell exactly what is happening, but it really made me want to read the article to find out. I didn’t know anything about these molecules before reading the paper and I still don’t think I can pronounce norbornene properly. But it was the energy of this otherwise static image that grabbed my imagination.

I’m not saying that drawings are not good enough. In fact I’ve said in the past just how informative a simple sketch can be and how an old drawn reaction scheme can be boosted with a huge golden frame around it. But sometimes a totally new look, a novel way of representing a reaction can work wonders. So, now that you’ve seen the covers, go and discover the real science behind both these images over at Chemical Science.

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Categories: Education

ISACS poster prizes 2015

Chemistry World blog (RSC) - 1 April, 2015 - 11:52

ISACS, the International Symposia on Advancing the Chemical Sciences, is a series of meetings where some of the world’s greatest researchers gather to discuss key chemistry topics. It’s a great opportunity to get up to date with the topic in hand, and the extensive poster sessions are a good chance for early career researchers to network with big-hitters in their field. To encourage more researchers to attend and present their work, Chemistry World will be sponsoring prizes for the best posters at all three ISACS meetings of 2015. Winners will receive £250, a highly sought-after Chemistry World mug and a certificate.

To take advantage of this amazing opportunity to showcase your latest research alongside leading scientists submit your poster abstract by 7 April for ISACS16, by 29 June for ISACS17 and by 7 September for ISACS18.

Read more about last year’s winning posters, and the scientists behind them, here!

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March 2015: Building a stronger future

Royal Society R.Science - 31 March, 2015 - 17:47

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Question time

Chemistry World blog (RSC) - 26 March, 2015 - 16:44

Guest post by Heather Cassell

Throughout my time in the lab I have greatly appreciated having post docs, PhD students and technicians looking after me. So I try to be as supportive as I can to the students in the lab, especially the undergraduates. This mainly involves answering lab based questions, such as: ‘Do you know where this reagent is?’ ‘How do I get rid of this waste?’  Or ‘this is broken, what should I do?’ The questions are usually straightforward, and I’ll do my utmost best to help (unless I’m in the middle of setting up a big experiment – some people just don’t understand that setting up 64 well plates takes concentration!)


But sometimes the questions are more philosophical, asking if I enjoy working in science, or what the value of postgraduate studies such as a masters or PhD can be. The answer to the first question can vary from ‘yes, science is amazing’ to ‘no, run away whilst you can, science is awful, it has no future or jobs’, depending on how things are going in my project, how much paperwork I have to do, and how many meetings I have to attend.

I try to suppress my first reaction to the question (especially when it’s the latter) and give them an honest view of life as a PhD student and what it is like working on short term contracts as a post doc; many students don’t realise that post docs are short term contracts and that when the money is gone so is the job. I’m happy to talk about the different options open to students once they have finished their undergraduate degree, especially as lab based science doesn’t suit everyone.

It’s not just the undergraduates that have questions. I also enjoy talking to the PhD students, especially discussing their results and helping them decide what they should do next. But here again, timing is everything. As nice as it is to be able to lean on my own experience to help people at an earlier stage in their careers, I sometimes use these ‘agony aunt’ sessions to help my own projects out: if I’m filling tip boxes, making buffers or other lab prep, I’d love to talk about your work, especially if you help me fill boxes as we talk! I think that’s a fair arrangement, don’t you?

So if you’re an undergraduate considering a career in scientific research, why not find a post-doc in your lab, help them prep their buffers and learn what that career has in store for you?

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Categories: Education

Volunteers for Viagra

Chemistry World blog (RSC) - 19 March, 2015 - 13:21

Guest post by Rowena Fletcher-Wood

It was the 1990s, and drug giant Pfizer was on the trail of an elusive angina medication to relieve constricted blood vessels and lower blood pressure. Pharmaceutical chemists in Sandwich, UK, were focusing their efforts on drugs that release NO (nitric oxide), a highly reactive radical that expands blood vessels and releases physical tension. One promising candidate was sildenafil, which was trialled in Morriston Hospital, Swansea.

It’s always difficult to recruit volunteers for a drug trial: even the best trials in animals, computer simulations and in vitro can’t take into account the full complexity of the human body, it’s strikingly unobvious differences from the rat and the complex interconnectedness of its mechanisms. Unexpected things happen, some of them bad, and some of them beneficial.

Sildenafil, later renamed Viagra for marketing, seemed to be a no-go for angina relief, and the trials were unsuccessful. Pfizer recalled the drug, and an unexpected thing happened: the volunteers resisted. ‘[P]eople didn’t want to give the medication back’, said Pfizer’s Brian Klee, ‘because of the side effect of having erections that were harder, firmer and lasted longer.’

At once, Pfizer started to investigate these reports. Using penile tissue from impotent men, senior scientist Chris Wayman introduced pulses of electricity both before and after introducing Viagra to their surrounding solution. The effect was immediate and pronounced: Viagra-treated tissue relaxed its blood vessels where untreated tissues did not, just as phallic vessels would relax to welcome the heavy flow of blood to the region. This revealed another significant property of Viagra: limiting erections to when the patient was sexually stimulated – and so foregoing the social inconvenience and dangerous blood restriction of constant arousal.

Catalytic domain of human phosphodiesterase 5 with bound Sildenafil. Image by A2-33 (Own work) CC BY-SA 3.0, via Wikimedia Commons

Pfizer was as impressed as the volunteers. One thing led to another, and very soon Viagra was on the market, and selling at an unprecedented rate as the first oral treatment for erectile dysfunction. Although other treatments did precede Viagra, they were not comfortable options: regular injection or an unpleasant prosthetic implant.

Viagra works in a very clever way, by mimicking a compound in the body and so blocking one of the enzymes that it binds to: the enzyme binds Viagra instead, and its function is blocked. This enzyme is PDE-5, a phosphodiesterase, and it works by mopping up cGMP, or cyclic guanosine monophosphate, which is the stuff that provides the erection. How? It all comes back to NO. Naturally produced by the stimulated brain, NO basically sets up a small factory making cGMP, only to have it swallowed up and broken back down by PDE-5, unless Viagra comes along. It’s striking chemical similarity to cGMP is enough to confuse PDE-5, inhibiting its action and leading to increased cGMP levels. Viagra is naturally decomposed and cleaned out by the body, with no further effects than a prolonged reaction to stimulation and a surprising effectiveness in relieving altitude sickness.

Worth volunteering for?

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Categories: Education

Academic family: Adolf Butenandt and Richard Kuhn

Chemistry World blog (RSC) - 12 March, 2015 - 12:11

Guest post by JessTheChemist

‘In order to avert such shameful occurrences for all future time, I decree with this day the foundation of a German national prize for art and science. Acceptance of the Nobel prize is herewith forbidden to all Germans for all future time. Executive orders will be issued by the Reich minister for popular enlightenment and propaganda.’ – Adolf Hitler, 1937

Portrait of Richard Kuhn
By ETH Zürich (ETH-Bibliothek Zürich, Bildarchiv) CC BY-SA 3.0, via Wikimedia Commons

Since my February blog post on Carl Djerassi, I have been wondering more and more about all the chemists out there who may have deserved a Nobel prize in chemistry but perhaps died before they could be awarded one or who were prevented from winning a medal for reasons out of their control.

It is well known that the second world war led to huge advancements in chemistry, with, for example, the first organophosphate compounds developed. These were initially used as deadly chemical weapons but have since changed the world through their use as pesticides. While many German scientists were advancing their field, two were forced to decline their Nobel prize in chemistry due to threats of violence and a decree by Adolf Hitler. These talented chemists were Adolf Butenandt from Austria and Richard Kuhn from Germany.

In 1929, Butenandt isolated estrone, a female sex hormone responsible for sexual development and function. He later isolated and identified androsterone, a male sex hormone. Butenandt was awarded the Nobel prize in chemistry in 1939, along with Leopold Ružička, for the identification of the sex hormones including oestrogen, progesterone and androsterone. Kuhn is known for synthesizing vitamins B2 and B6 and discovering carotenoids, the red and yellow coloured biological pigments. He also discovered the nerve agent Soman (o-pinacolyl methylphosphonofluoridate) while carrying out research for the German army. In 1938 Kuhn was awarded the Nobel prize for chemistry for his work into carotenoids and vitamins. Both Butenandt and Kuhn declined their prizes due to political pressures but were both able to accept their medals and diplomas after the war.

Butenandt and Kuhn’s academic family trees are intertwined and contain a number of very well-known names that you may recognise from your lab cupboards (including Bunsen and Schlenk). In 1902 the German chemist, Hermann Fischer, won the Nobel prize in chemistry for his discovery of the Fischer esterification. A few years later, in 1905, Adolf von Baeyer won the prize for his work into organic dyes and hydroaromatic compounds. Richard Willstätter, yet another German chemist, researched the structure of plant pigments, including chlorophyll, and won the prize in 1915. Adolf Windaus won in 1928 for his work on sterols and vitamins. In addition to chemists, Butenandt and Kuhn are both connected to Otto Warburg, a physiologist who investigated the metabolism of tumors and the respiration of cells. In 1931 he was awarded the Nobel prize in physiology for his work into the respiratory enzyme.

What is very obvious from this academic tree is that both of these chemists were destined to excel in chemistry due to the sheer number of Nobel prize winners that they are connected to. Another obvious conclusion is that chemistry was really progressing in Germany before the second world war; at the beginning of the 20th century, Germany won more Nobel prizes than any other country (38 between 1901 and 1931). After the second world war, Germany’s domination in science was reduced significantly and only 16 Nobel prizes were awarded to German scientists between 1950 and 1980.

As ever, if you would like to see your favourite or even least favourite Nobel prize winner’s family tree explored, send a tweet to @Jessthechemist.


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