The Nobel Prize in Chemistry 1981

Roald Hoffmann

Every chemist is familiar with the Woodward-Hoffmann rules that predict the products of reactions in organic chemistry. The theory was the result of collaborations between Robert Burns Woodward (1917-1979), the organic chemist, and Roald Hoffmann, the theoretical chemist. Both went on to win Nobel prizes–Woodward in 1965, for his work with natural products, and then Hoffmann in 1981, his prize specifically recognizing the importance of his theory in explaining organic chemistry by the behavior of electrons and the molecular orbitals in which they move. In his time, Hoffmann has published in many areas, as is demonstrated in the listing of his most-cited papers.

Roald Hoffmann is also a literate chemist, as we can see from his recent book Chemistry Imagined: Reflections on Science. This is a joint publication with the artist Vivian Torrence, and combines essays, poems, and articles with a series of collages inspired by chemistry. Torrence has been a visiting scholar at Cornell University in Ithaca, New York, where Hoffmann is Professor of Physical Science, and her work has been exhibited in art galleries across the United States. Hoffmann's literary achievement shows that chemistry can be a worthwhile, if unexpected, subject for poetry and prose.

Hoffmann was born in eastern Poland in 1937, just before that part of his native country was occupied by the Soviet Union in 1939. In 1941 it was overrun by the Nazis, and although he was of Jewish parents, Hoffmann survived the Second World War. He emigrated to the U.S. in 1949, settled in New York, and went to Stuyvesant High School. From there he went to Columbia College and graduated in 1958. His next stop was Harvard, where he was awarded an M.A. in physics in 1960 and a Ph.D. in chemical physics in 1962, working under the supervision of Martin Gouterman and William Lipscomb. His research involved applying the theory of molecular orbitals to polyhedral collections of atoms.

Hoffmann continued at Harvard as a Junior Fellow. He met his wife Eva at a summer school in Sweden, and they eventually had two children, Hillel and Ingrid. Meanwhile he began his collaboration with Woodward, and together they developed the theory that now bears their names. This was written up in five benchmark papers that were published in 1965 while Hoffmann was still only 28. Their impact was immediate and they quickly became a part of every organic chemist's vocabulary. Hoffmann then moved to Cornell to his first teaching post and was promoted to professor in 1968.

In 1972 Hoffmann was elected to the National Academy of Science and two years later became the John A. Newman Professor of Physical Science at Cornell. In 1981 Hoffmann won the Nobel Prize for chemistry, which he shared with Kenichi Fukui. The following year the American Chemical Society gave him their Inorganic Chemistry award, attesting to the span of Hoffmann's influence–by this time he was transforming the theory that underpins this area of the subject, just as he had once transformed organic chemistry.

I came to a happy Jewish family in dark days in Europe. On July 18, 1937 I was born to Clara (née Rosen) and Hillel Safran in Zloczow, Poland. This town, typical of the Pale of the Settlement, was part of Austria-Hungary when my parents were born. It was Poland in my time and is part of the Soviet Union now. I was named after Roald Amundsen, my first Scandinavian connection. My father was a civil engineer, educated at the Lvov (Lemberg) Polytechnic, my mother by training a school teacher.

In 1939 the war began. Our part of Poland was under Russian occupation from 1939-1941. Then in 1941 darkness descended, and the annihilation of Polish Jewry began. We went to a ghetto, then a labor camp. My father smuggled my mother and me out of the camp in early 1943, and for the remainder of the war we were hidden by a good Ukrainian in the attic of a school house in a nearby village. My father remained behind in the camp. He organized a breakout attempt which was discovered. Hillel Safran was killed by the Nazis and their helpers in June 1943. Most of the rest of my family suffered a similar fate. My mother and I, and a handful of relatives, survived. We were freed by the Red Army in June 1944. At the end of 1944 we moved to Przemysl and then to Krakow, where I finally went to school. My mother remarried, and Paul Hoffmann was a kind and gentle father to me until his death, two months prior to the Nobel Prize announcement.

In 1946 we left Poland for Czechoslovakia. From there we moved to a displaced persons' camp, Bindermichl, near Linz, in Austria. In 1947 we went on to another camp in Wasseralfingen bei Aalen in Germany, then to München. On Washington's Birthday 1949 we came to the United States.

I learned English, my sixth language at this point, quite quickly. After P.S. 93 and P.S. 16, Brooklyn, I went on to the great Stuyvesant High School, one of New York's selective science schools. Among my classmates were not only future scientists but lawyers, historians, writers - a remarkable group of boys. In the summers I went to Camp Juvenile in the Catskills, a formative experience. Elinor, my younger sister, was born in 1954.

In 1955 I began at Columbia College as a premedical student. That summer and the next I worked at the National Bureau of Standards in Washington with E.S. Newman and R.E. Ferguson. The summer after I worked at Brookhaven National Laboratory, with J.P. Cumming. These summers were important because they introduced me to the joys of research, and kept me going through some routine courses at Columbia. I did have some good chemistry teachers, G.K. Fracnkel and R.S. Halford, and a superb teaching assistant, R. Schneider. But I must say that the world that opened up before me in my non science courses is what I remember best from my Columbia days. I almost switched to art history.

In 1958 I began graduate work at Harvard. I intended to work with W.E. Moffitt, a remarkable young theoretician, but he died in my first year there. A young instructor, M.P. Gouterman, was one of the few faculty members at Harvard who at that time was interested in doing theoretical work, and I began research with him. In the summer of 1959 I got a scholarship from P.O. Lowdin's Quantum Chemistry Group at Uppsala to attend a Summer School. The school was held on Lidingö, an island outside of Stockholm. I met Eva Börjesson who had a summer job as a receptionist at the school, and we were married the following year.

I came back to Harvard, began some abortive (and explosive) experimental work, and Eva and I took off for a year to the Soviet Union. It was the second year of the U.S.-U.S.S.R graduate student exchange. I worked for 9 months at Moscow University with A.S. Davydov on excitor theory. Eva and I lived in one of the wings, Zona E, of that great central building of Moscow University. My proficiency in Russian and interest in Russian culture date from that time.

On returning to the U.S. I switched research advisors and started to work with W.N. Lipscomb, who had just come to Harvard. Computers were just coming into use. With Lipscomb's encouragement and ebullient guidance, L.L. Lohr and I programmed what was eventually called the extended Hückel method. I applied it to boron hydrides and polyhedral molecules in general. One day I discovered that one could get the barrier to internal rotation in ethane approximately right using this method. This was the beginning of my work on organic molecules.

In 1962 I received my doctorate, as the first Harvard Ph.D. of both Lipscomb and Gouterman. Several academic jobs were available, and I was also offered a Junior Fellowship in the Society of Fellows at Harvard. I chose the Junior Fellowship. The three ensuing years in the Society (1962 - 65), gave me the time to switch my interests from theory to applied theory, specifically to organic chemistry. It was EJ. Corey who taught me, by example, what was exciting in organic chemistry. I began to look at all kinds of organic transformations, and so I was prepared when in the Spring of 1964 R.B. Woodward asked me some questions about what subsequently came to be called electrocyclic reactions. That last year at Harvard was exciting. I was learning organic chemistry at a great pace, and I had gained access to a superior mind. R.B. Woodward possessed clarity of thought, powers of concentration, encyclopedic knowledge of chemistry, and an aesthetic sense unparalleled in modern chemistry. He taught me, and I have taught others.

The 1962 - 65 period was creative in other ways as well: Our two children, Hillel Jan and Ingrid Helena, were born to Eva and me.

In 1965 I came to Cornell where I have been ever since. A collegial department, a great university and a lovely community have kept me happy. I am now the John A. Newman Professor of Physical Science. I have received many of the honors of my profession. I am especially proud that in addition to the American Chemical Society's A.C. Cope Award in Organic Chemistry, which I received jointly with R.B. Woodward in 1973, I have just been selected for the Society's Award in Inorganic Chemistry in 1982, the only person to receive these two awards in different subfields of our science.