Issue Date: January 5, 2015
Missing A Colleague And Friend
Paul von Ragué Schleyer was unique in having two successful careers as a chemist. He was a highly energetic and productive experimental physical organic chemist during his years as a professor at Princeton University. In 1976, he left Princeton to accept a professorship at Erlangen in Germany and at the same time completely changed his research career and became a computational chemist. It is his success in this area that continued right up until his death that is remembered by most chemists (C&EN, Dec. 8, 2014, page 50).
Nevertheless, his accomplishments as an experimental physical organic chemist were impressive and important. When he was a graduate student in the chemistry department at Harvard University, his mentor, Paul Bartlett, assigned him a research topic concerning terpene chemistry. Terpenes are organic molecules notable for the ready rearrangement of their carbon skeletons, generally under acidic conditions. Paul thoroughly studied the literature in this area and then organized it and interpreted it in writing his Ph.D. thesis. It was the fattest thesis I have ever seen.
He continued working in this and many other areas of organic chemistry at Princeton. Many of his novel ideas concerning kinetics and mechanisms of reactions came from this period. He made important contributions to our knowledge of interactions related to hydrogen bonding.
It surprised many organic chemists that Paul largely abandoned this work and turned with great enthusiasm and energy to computational chemistry. It is also striking that he left the U.S. and entered the somewhat different academic environment of Germany at the same time. His main contribution was to use his deep and detailed knowledge of organic chemistry and reaction mechanisms in connection with computer programs using quantum mechanics. He said that he used these programs as black boxes to predict energies and structures. These predictions became more and more accurate as computer programs employing quantum mechanics were more highly refined and improved and as computers became faster. Many of the questions Paul asked simply would not have occurred to the theoretical chemists developing quantum mechanics.
A thread that connects Paul’s early work on terpene rearrangements in the 1950s at Harvard with his recently published paper on the X-ray crystal structure of the norbornyl cation is the decades-long nonclassical ion controversy. Paul, George Olah, and I have been heavily involved in this discussion. I recently talked with Paul about the background of the communications that the three of us published in 1964 on the NMR spectrum of the stable norbornyl cation in solution. Paul prepared norbornyl fluoride (Olah initially believed that fluorides were required for making carbocations). He sent it to Olah at the Dow Chemical Eastern Research Lab in Framingham, Mass. It was there converted to the cation. One of Olah’s coworkers then brought an NMR tube containing the ion, cooled in a Dewar flask with dry ice, on a train to New Haven, where I took the low-temperature NMR spectrum.
I am sure that I can speak for Paul’s many friends and collaborators in saying that he will be greatly missed.
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