Ekkehardt Hahn talks about carbenes, German research and his run-in with the Czech border air police. Interview by Ruth Doherty

Ekkehardt Hahn is a professor of inorganic chemistry at University of Münster, Germany. His research is focused on the coordination chemistry of N-heterocyclic carbenes and stannylenes and also making complexes of technetium, rhenium and galolinium with tetradentate ligands for use in medical-diagnostics. He recently became a Fellow of the Royal Society of Chemistry and is also a member of the Dalton Transactions editorial board.

Who or what inspired you to become a scientist? 
When I was about 14, one of my sisters got a chemistry kit for Christmas. It contained two chemicals that formed a transparent polymer when mixed together and you could place small objects in the mixture before it hardened to make a key chain or a necklace. It had a warning that improper mixing could lead to a serious accident, which scared my sister and made me the owner of my first set of chemicals! I guess it started there and I still remember how impressive it was to make a transparent glass-like solid from two liquids. 

What attracted you to study carbenes? 
I graduated from the group of Professor Herbert Schumann in Berlin who was heavily involved in group 14 chemistry. When I started my independent career, I decided to work with organotin(ii) compounds, particularly N-heterocyclic stannylenes. From there it was only a small step to N-heterocyclic carbenes (NHCs). 

What is going to be the next big thing in your field? 
NHCs have been used in coordination chemistry and organocatalysis and new types of stable cyclic and acylic heterocarbenes emerge regularly. With many research groups worldwide engaged in carbene research, it is difficult to predict the direction of the development for the next years. I believe that the metallosupramolecular assemblies with polycarbene ligands are promising new compounds where the metal-NHC interaction not only serves to hold the supramolecular structure together but also generates a catalytically active carbene species. 

Since the recession, has science funding in Germany been reduced? 
I have not felt any reduction in funding over the last two years. That may be an individual observation but I believe it is generally true in Germany. More disturbing is the transformation that science, chemistry in particular, has undergone in the public forum. 30-40 years ago chemists were considered problem solvers by providing new materials or drugs. Now the media often paint a dark picture in which chemistry is accused of pollution and many environmental scandals. 

Germanyis a country well known for its sense of invention - the automobile, Bakelite, coffee machines; do you feel this will continue? 
Young people in Germany studying science are enthusiastic, well trained and a pleasure to work with. I have observed that chemists are most productive when they are left to do what they can do best without focusing on so-called 'hot topics' or the need for quarterly progress reports. Fortunately, the German Science Foundation (DFG) initiated a programme where junior scientists with no permanent position can receive funding for 5 years to pursue the research of their choice. My group hosts such a junior scientist who came to us from Canada and I am pleased to see that the concept works. I believe that sufficient funding and academic freedom are the important elements to keep invention going. 

You have lived and worked both in Germany and the USA. How do the science policies in these countries differ? 
One difference is the tuition fees. Students in the US did not like, but fully accepted, the need to pay fees. But, introduction of relatively small fees by universities in Germany a couple of years ago led to endless discussions. The fees in the US, however, did not prevent a deteriorating funding situation that I have observed over the last years. This appears to hurt many junior researchers in the US starting their career. 

You are a qualified pilot - why did you learn to fly? 
My brother-in-law owned a Safari business and operated a number of single engine planes in Nairobi, Kenya. A couple of months before I started a postdoc in Berkeley, US, I went flying with him and greatly enjoyed it. I discovered the UC Berkeley flying club on my arrival and decided to learn to fly there. 

Have you ever had any incidents when flying? 
Fortunately, I've never had a flying accident but I did have a memorable incident some years ago. In the 1990s I was the chairman of the local Berlin chapter of the German Chemical Society. After one seminar I offered to fly the speakers around the city or to the next stop of their journey. Those brave enough to accept the offer included the president of TU Munich, W. A. Herrmann, and his wife, who were going to Dresden. We took off from Berlin but by pilot error went too far south over Czech territory, which we discovered when planes and helicopters with red stars showed up in the air next to our plane. We were escorted to the Karlovy Vary airfield in the Czech Republic to land. This was in 1995 when the military blocks in Europe still existed and crossing an international border without a flight plan and prior permission was considered an act of air piracy. Fortunately, the legal rules were not applied to their full extent and we continued to our destination after a two-hour 'stopover'. 

Where is your favourite place you have flown yourself to? 
Among the most impressive flights I have taken over the last 25 years are a night flights over the San Francisco Bay in the US and flights over Table Mountain in Cape Town, South Africa. 

If you could solve any scientific problem in any field, what would it be? 
I have seen both family and friends dying from cancer. This horrible disease has clearly a biochemical origin but chemists have so far failed to unravel the chemical secret. I am afraid, however, that carbene chemistry will not significantly contribute to this research.