It is impossible to know with certainty whether Dmitri Mendeleev envisioned the first draft of the periodic table while snoozing, or if Paul McCartney was actually inspired by Morpheus to compose “Yesterday”, the iconic Beatles song. Otto Loewi (1873-1961), the German pharmacologist who discovered the role of acetylcholine in the transmission of nerve impulses, claimed that he first dreamed the critical experiments that eventually led to his Nobel Prize in Physiology or Medicine in 1936. Would any of these creative accomplishments be less significant had they not been concocted when their authors were asleep?
The case of the hexagonal structure of benzene, first proposed by the eminent German organic chemist August Kekulé (1829-1896) in a paper published in 1865 in the Bulletin de la Société Chimique de Paris, is perhaps a little more peculiar. It was only 25 years later that Kekulé, speaking about his seminal contributions to structural organic chemistry at the legendary Benzolfest held in Berlin, disclosed publicly that the original idea for the cyclic structure of benzene was derived from a reverie he experienced in which a snake was biting its own tail (i.e., a vision of the mythical ouroboros). It doesn’t really matter if Kekulé’s belated revelation was completely accurate, or if the story was embellished over time to enhance its pedagogical value. The fact is that Kekulé’s chemical intuition and insightful work in the second half of the 20th century has had a profound effect in the development of modern organic chemistry, including the highly scrutinized concept of aromaticity.
Kekulé, who was a chemistry professor at the University of Ghent (1858-1867) when he suggested the correct molecular structure of benzene 150 years ago, was honored with a postage stamp issued in Belgium in 1966. The sesquicentennial of Kekulé’s birth in the city of Darmstadt was similarly commemorated by the German Democratic Republic in 1979. Interestingly, both stamps feature the classic structural representation of benzene as cyclohexatriene, with alternating single and double bonds, but unfortunately depict some incorrect interatomic angles for the prototypical aromatic molecule.
In closing, I must confess that I don’t know what I will be writing about in my next Stamps International note. I am always looking for interesting stories to illustrate with postage stamps so, in my quest for inspiration, perhaps all I need to do is relax and take a nap!
For a brief description of Kekulé’s purported dream, see: A.J. Rocke, Angew. Chem. Int. Ed. 2015, 54:46-50.
Written by Daniel Rabinovich <drabinov@uncc.edu>
©2015 by Walter de Gruyter Berlin/Boston
