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Denmark 1989 - First Impressions Flashback, December, 24 years ago, Kastrup airport, 6am, the plane (yes, really!) to Odense is, less surprisingly, delayed due to fog, snow and high winds. 26 hrs and 35 degrees earlier it was a sunny day in Melbourne, and 4 weeks until Christmas. WHAT was I thinking? Several hours later, finally, take-off for the 30 min flight. One hour, and some circling, later, the pilot announces that we can’t land in Odense due to bad weather, so we will land in Billund. WHERE! The German guy next to me doesn’t have a clue. Is it even in lilliputian Denmark? Once at the airport I ask how to get to Odense. WHERE? Never heard of it the lady at the information desk responds. 40 hours without sleep and I am really starting to loose my sense of humor and adventure. I write it down for her – it helps. Oh OENSAY! She points me to a bus with Turistfart disturbingly written on its side. The situation does not get any less surrealistic - only darker - its midafternoon - soon I pass by Middlefart (= halfway between [Hors’-ends] and [Ass-ends]!). Next day, jetlagged, haze. How will I get from my flat in Skt. Jørgensgade to Odense University when it is snowing? I wait for a bus and several drive past me without stopping (apparently because they were full). Do Danish buses not pick up freezing and distraught Australian girls? I arrive at the lab nearly 2 hours later with only minor frost bite and my sense of humor barely intact. I can’t remember the names of anyone I am introduced to, see lots of outrageous behavior (smoking in the office – and the lab, beer in vending machines). Soon it is dark again.
r of my apartment block-27 doo nt fro the side out e ens Od of w vie My first hours after landing in Kastrup! 22
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A few hours later after I had found the university. - I needed to buy my first winter coat!. The iron cladding on the buil ding seems now to have been a sign of the chemistry that was yet to come. Institute Christmas party. Starts at lunch time! In the department! Didn’t have a clue what was happening: Had to change seats abruptly several times without any reason that I understood. Play silly games. Sing incomprehensible words to unknown tunes. Drink snaps and beer with the professors! The partygoers were markedly less reserved compared to their alias’ during the previous two weeks. I had never been to such a long party in my life - the stragglers including me were still “at work” after midnight dancing. I can still hear Gnags (Mr Swing King) in my head. New Year’s Eve, like for Christmas my colleagues in the lab kindly made sure I had a place to be, not that I thought anyone should be anywhere except wrapped up in a doona at those temperatures. I was told that the dress code for New Year’s is formal. Apart from the fact that my suitcase had not allowed for this – HOW can this even be possible? It’s snowing and there was black ice on the footpaths. Weather for ski suits and spiked cramp-ons. I slid the streets to the party to meet Cinderalla’s magically transforming in the entrance hall; gummistøvler to stilettos, ski suits to strappy frocks. Why didn’t anyone tell me? At midnight, fireworks are set off by the enthusiastic revelers using their cigars to light them! I was terrified. Fireworks are banned for private use in Australia (admittedly there is a higher fire risk). Next 24 years have flown by: Post doc – first baby (now a student at SDU!) – Post.doc. – assistant professor – second baby – associated professor – full professor Ø
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85 (green two color B.Sc.Ed., B.Sc.(Hons) 19 emic gown) cape over black acad
Ph.D. 1990. (red cape and bord ers over black aca demic gown and best - a floppy velv et hat with tass l e ). Ph.D. graduates get to join the academic procession through the “old law” at The Universit y of Melbourne. It is a very colorful pa rade since the staff at Melbourne Un iversity come fr om al over the world. The Vice Chanc ellor and Professors in the procession wear the academic gowns from thei r own Alma maters.
“Welcome Strang ers” - the lagest gold nugget ever fo und! It was disc overed in 1869 in Aust ralia - only 6 km from my grandmothe r’s house.. The picture is a wood engraving published in The Illustrated Austra lian News, 1869. The scale bar across the bott om represents 30 cm . 24
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Why Chemistry? Growing up in Australia meant my introduction to inorganic chemistry was early. The geology, landscape and mining are a dominant part of the culture and industry. My teenage years were spent less than one km from two “poppet heads” in Bendigo, a provincial Australian city which grew out of the gold rush in the 1850’s. Gold is still mined in hundreds of kms of tunnels under Bendigo. We kids kept a constant sharp eye out for specs of gold and I knew at a very young age that crystal facets distinguish pyrite (fool’s gold) from real gold. The central importance of chemistry in our lifestyle, and economy seemed obvious to me, but I have to admit, I never did chemistry experiments at home in the kitchen other than when making Pavlova. A decade later, to my astonishment, this girl from the “bush”, managed to complete a Ph.D. in inorganic chemistry at The University of Melbourne. My research involved the synthesis of new palladium compounds and study of their catalytic properties. A Ph.D. degree gave me an opportunity to live abroad while I worked as a post doc. My plan was to do this for a couple of years before returning to Oz and spending the rest of my life in the sun, with a well-paid job in industry. I was trying to choose between the career-wise choices of post doc offers at The University of Chicago and Osaka University when my supervisor got a letter from the late Prof. Hans Toftlund enquiring as to whether he had any graduates from his group interested in coming to Denmark. Scandinavia and Europe appealed to me, and the rest is history. Ø
My son outside the “Central Deborah Gold Mine” and one of the two “poppet heads” in downtown Bendigo, 1 km from my teenage home. Here you can be transported ½ km underground and see actual gold in the quartz veins running under the city.
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Uluru is one of Australia’s examples of amazing geology. It is a sand-
stone formation which is 348 m high. It is rich in iron oxide giving the beautiful colour. Uluru is sacred to the aboriginals in the area.
Oz and Aussies
Australians, or Aussies, use heaps (a lot) of slang and nick names and whenever possible they shorten words and use abbreviations. Australia is pronounced O-ss-tray-lee-a - Oz-tralia, thus ‘Oz’. Further the Aussies play with the Australian language. A very common saying you will meet Down Under is: Do you want bangers with dead horse and mash? And yes, it is safe to order this! (Do you want sausages with tomato sauce and mashed potatoes)
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Australian tradi tional art by a boriginals.
Iron is
a transition metal, has number 26 in the periodic table and the chemical symbol is Fe (from latin: ferrum). Its position in the periodic table (group 8) means it can be found a wide range of oxidation states. Most are reactive and +2 and +3 are by far the most common. Iron can undergo a well-known oxidation, namely rusting. Rust is made up of iron oxides, usually iron(III) oxides Fe2O3*nH2O and iron(III) oxide-hydroxide FeO(OH), Fe(OH)3. Theses oxides are formed when iron reacts with oxygen in the air in the presence of water or air moisture. Iron oxide can come in red, yellow and black. These make up the palette used by the Australian aboriginals in their traditional art. Of course iron oxide is architectually iconic for SDU! 27
s e fol owing notes l a t s y r C t u o b urther with my story in th A s e t o N e m So ip and go f also sk -> you can
The word
crystal
is derived from the Ancient Greek word krustallos meaning “ice” and “rock crystal”.
A single crystal is a solid material build-up of atoms, molecules or ions in a highly ordered structure giving a near-perfect periodic arrangement. The atoms, molecules or ions of the crystal are stacked repeatedly in unit cells giving a three dimensional crystal lattice. Crystals are formed via mechanisms of crystal growth called crystallization. A given compound will crystallize in its own unique shape and crystals can be recognized by their morphology and colour. During the crystallization process some defects can be introduced to the repeatedly pattern causing crystallographic defects for example like twinning. A twin has two sets of the same crystal lattices in the crystal; however these are rotated relative to each other, therefore it is no longer a single crystal but two identical ones grown into each other.
Twined pyrite. is a mineral co mposed of FeS2 metallic luster . The mineral’s and hue give it a superficia tual gold. The l similarity to ac name fool’s go ld derived from days, when ap the old mining parently inexp erienced gold minor pieces of miners mistook the mineral fo r gold.
Single crystal - the atom makes a near perfect periodic pattern
Polycrystal - consist of many small crystals.
Due to the ordered pattern of atoms within a single crystal, crystals can diffract, spread, X-ray radiation.
Diffraction
is a physical phenomenon which occurs when a wave encounters an obstacle or a slit. This is however only happening when the wavelength of the radiation is roughly comparable to the dimensions of the diffracting object. The wavelength of X-ray radiation is approximately 0.01 - 10 nm, and typically atoms are 0.1-0.3 nm apart in materials,. This make X-rays perfect for determination of crystal structures. The property of diffraction is used in X-ray crystallography; as the beam penetrates the material, the beam will spread to form a diffraction pattern. Based on this diffraction pattern, it is manageable to determine the crystal structure of the crystal. Crystallography is the chemist’s way to photography - we take pictures on an atomic level.
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I
Crystals omer
(S)-enanti
Example of diffraction patterns, which contain structual information about the crystals.
If a single crystal can undergo a change, however remain crystalline and not break through the change, a so-called single crystal to single crystal transformation has taken place. This is really rare, because crystals are so perfectly packed, just small chemical changes will cause dramatic changes in the crystal lattice, and the crystal will crack, break, fall apart etc. A stereo- and regioselective reaction is a reaction where only one out of many possible products is formed. For example in this oxidation reaction, oxidation can take place at the benzene-ring or the alkene bond, however only the alkene bond, is oxidized. Further only one of the enantiiomers of the reactent epoxide is formed. This is a stereoselective reaction.
A redox reaction occurs when a transfer of electron(s) between atoms takes place. One atom in the reaction will be oxidized and another atom will be reduced. In an oxidation the reductant loses electron(s), and the oxidation number increases. The oxidation number indicates the number of electrons an atom has in its “outer shell”, these electrons are the important ones, since these are the ones that are used in chemical reactions. Chemists call these “outer shell”-electrons, valence electrons. On the other hand in a reduction the reductant gains electrons and the oxidation number decreases..
Example Oxidation: Reduction:
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What is the point of the new materials we make? My group focuses on the synthesizing new materials based on the transition metal ions, and in particular the metal ions that are employed by biology as the crucial co-factors in enzymes. Without metalloenzymes no life would exist. They catalyze the hardest reactions of all, e.g. the conversion of N2 in the air to ammonia to use in the biosynthesis of basic biological building blocks, amino acids and nucleic bases, and the splitting of water in photosynthesis in order to create biological energy (electrons and protons). There is an obvious link in understanding metalloenzymes and designing new catalysts that can perform the feats than Nature can. There will be many applications. For example, in “Artificial Photosynthesis” where the ultimate aim is to use sunlight which can activate transition metal catalysts to split water and make hydrogen for fuel. Achieving this would mean that carbon can be cut out of the energy cycle with the consequent reduction in the CO2 influx into our atmosphere. We have synthesized “functional” models (i.e. materials that perform some of the same chemistry as metalloezymes even though they look nothing like them) for Hemoglobin, Aromatic hydroxylases, Amine oxidases, and even the Oxygen Evolving Center in photosynthesis. Using iron-based molecules we can “activate” O2. This is a crucial step for catalyzing oxidation reactions in which O2 from air is used as the terminal oxidant. Such catalysts will be enormously important in the future for making the production of pharmaceuticals significantly greener. Today oxidation processes, in particular, produce enormous amount of waste. This will be alleviated if O2 can be used in stereoand regio-selective oxidations of important drug precursors.
, which transports l other vertebrates al d (in an , od o bl r ou e provides energy enzyme in oxygen in the tissu of e as as e l re Hemoglobin uisngthe ns e tio Th nc fu s. e en s to our muscl cel s, because oxyg oxygen from our l olic processes in the ab energy we need et m the l t al ge r s l we ce po to uently our eq ns co P, the form of ATP) AT of n or in the productio an electron accept to live. iron-atom which is d) is made of an un bo e is en yg ox re on next page). Du haemoglobin (whe n in the structure ee (gr rin ds hy The active site of bin rp po en yg a ox ic ring, known as metalloenzyme. As ygen. held in a heterocycl e, it is known as a m zy en the in n state can bind ox al et m a 3+. Only the 2+ oxidatio of ce en 2+ es n the pr to Fe ur subunits, one iro es the iron from Fe chains folded into fo ide pt pe en to the iron it oxidiz ur yg fo ox of ds lobin is made up oglobin selectively bin The enzyme hemog red blood cel s. Hem the in d te ple, the diatomic ca o l is lobin en though, for exam ev , air per subunit. Hemog ric he osp m to the binding is the gases in our at structure. The key d an e siz compared to other in th bo aired electrons are are very alike paramagnetic (unp th bo e nitrogen and oxygen ar se the n, oxygen and iro ectrons). electronic states of tic (no unpaired el ne ag am di is n ge ro present) whereas nit
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Our research spans synthetic organic, organometallic and inorganic chemistry and biological inorganic chemistry. Some of the compounds in which reduced O2 is bound are very unstable and we use any spectroscopic technique we can think of to “see” them. On a couple of occasions we have even caught high-valent ironoxo compounds (iron in oxidation state +4 and +5) and molecular Fe-oxidant adducts. Along the way there have been many serendipitous discoveries. As university-based researchers we are privileged, and if we can find the resources, we can turistfart Haemoglobin also along unexpected roads: Apart from our aims at making metalloenzyme mimics, our new materials have been applied to vastly different fields, from the reversible sorption of O2, tags for identifying post-translationally phosphorylated sites in peptides, compounds which can function as molecular switches, to Positron Emission Tomography imaging (PET imaging and the principle behind are further discussed by Niels Langkjær in the section Veje Efter Universitet).
Crystals that Breathe Who doesn’t like crystals? Especially colored crystals! Some people even think they have healing powers. Crystalline materials are well-defined since atoms and molecules are placed in regular repeating patterns and Xray radiation can be diffracted is regular patterns. Using this we can “see” how the atoms are bonded together at atomic level. Thus we put some effort into crystallizing our compounds when they are stable and pure enough. Recently we observed a spectacular Single Crystal-to-Single Crystal (SC-to-SC) transformation. Such processes are rarely observed because crystals usually decompose when the molecules they contain change chemical structure. During this remarkable process the solid reacts with the O2 in the air. The crystals are almost “breathing”: O2 is flowing in and out of the crystal depending on the pressure and/or temperature of the surroundings. In fact the crystals chemisorb O2 with an affinity on par with hemoglobin. We were most pleased with this result, especially since we could publish it in 2014 – the UNESCO International Year of Crystallography. Ø
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A single crystal amazingly capable of being in two stable states. Left, when O is bound (4% by we ight, ca. 20 times the con2 centration of O in pure hemoglobin ). Right, when the O has 2 2 been expelled from the crystal. Yo u can see a movie of the SC-to-SC transformation at https://www.youtube.com/watch?v=gJ bG9FvgX0U.
What next? That’s what we can never be sure of when making new materials based on the transition metal ions. There is still much chemistry to be discovered, and it is not always predictable. But it is important to keep an open mind when we make materials that we were not expecting to be the result of otherwise well designed syntheses. We have ambitious goals. For example, since we have demonstrated proof of principle in creating new materials that can reversibly bind O2 from air, perhaps we will stumble over organometallic materials that reversibly bind other important gases, e.g. CO2 or H2. Or, maybe an iron-based catalyst that can be applied to the purification of waste water or something completely different – you never know what’s next… o
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The group, May 2014 in the back yard of my Swedish summer house before we attended a con ference in Lund.
In front of The Chemistry Departm ent 25 years after I arrived in snow - also 3 weeks before Christm as. Now my home knit is Scandinavian style.
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