Ernst David Bergmann

Ernst David Bergmann

ELSEVIER Journal of Fluorine Chemistry90 (1998) 157-159 I Ernst David Bergmann 1 Shlomo Rozen School of Chemisto:, Tel Aviv Universi~, Tel Aviv 699...

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Journal of Fluorine Chemistry90 (1998) 157-159


Ernst David Bergmann 1 Shlomo Rozen School of Chemisto:, Tel Aviv Universi~, Tel Aviv 69978, Israel

The main problem of writing a short biography of Professor Enrst David Bergmann is to do full justice in describing this phenomenon who has contributed so much to the birth and flowering of Israel science. Being one of his last students, I feel special bonding to this great man. Ernst David Bergmann was born in Karlsruhe on 18th October 1903. His parents, Rabbi Judah and Hedwig Rosenzweig Bergmann, personalities in their own right, produced an extraordinary brood. The atmosphere in the household must have been most stimulating when one considers the positions that Ernst, Arthur and Felix Bergmann held in MBased in part on a talk given by the late Professor D. Ginsbnrgon the occasionof Bergmann'sbirthday.

Israel. In 1908, when Ernst was five years old, the Bergmann family moved to Berlin. It was there that Ernst received his primary and secondary education. It was there in 1924, at the age of 21, that he began his doctorate work, and in 1927, at the age of 24, that he was awarded his Doctor's degree, s u m m a c u m laude by the University of Berlin. Bergmann's thesis work was done with W. Schlenk, and the collaboration between the two was carried over into the writing of a monumental textbook entitled "Ausfuhrliches Lehrbuch der Organischen Chemie". The first volume published in 1932 has on its title page the names of the authors W. Schlenk and Ernst Bergmann. The second volume was published in 1939. But it is not surprising that on this publication his name disappeared and he did not receive credit as author. In 1929, Richard Willstatter proposed Bergmann, whom he had not met personally, as his successor to the chair of organic chemistry at the ETH in Zurich. The older and more well known Ruzicka was appointed to the chair and Bergmann become prime candidate for the chair at the Technische Hochschule in Charlottemburg in 1932, after the post, held by Pschorr, stood vacant for three years. For obvious reasons, however, in Germany of that time he did not actually get the appointment. Clearly, Bergmann did not remain long in Berlin. The Nazi era was beginning and Bergmann appreciated its implications long before many of his compatriots. Concurrently, Bergmann was introduced to Weizmann by Carl Neuberg and was offered the scientific directorship of the projected Sieff Institute in Palestine--the future Weizmann Institute. He was also invited by Sir Robert Robinson to join his staff at Oxford. Bergmann's Zionist background swayed him towards the former offer and in 1934 he arrived in Palestine and the story goes (and I have no doubt of its truth) that Bergmann himself serubbed the stairs in the Sieff Institute building on the eve of its formal opening. During the next few years which were happy and fruitful ones for him, he published more than eighty papers but this trend was interrupted by World War II. In 1940 Bergmann joined Weizmann in England and worked on various projects at the Grosvenor Laboratories contracted for by the Ministry

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S. Rozen / Journal of Fluorine Chemistry 90 (1998) 157-159

of Supply. This was the period when the Catarole (catalytic aromatization of olefins) process was developed. In 1942 Bergmann accompanied Weizmann to the United States where discussions were held on the production of monomers, required particularly for synthetic rubbers, from agricultural raw materials. Bergmann lived for a year in Terre Haute, Indiana, where he worked together with Commercial Solvents scientists on similar problems. He continued working for the Ministry of Supply until his return to the SieffInstitute in 1946. The Israel Independence war in 1948 was a hectic period. It was also the period of expansion and transformation of the Sieff Institute to the Weizmann Institute of Science whose Scientific Director Bergmann became in 1949. He was indefatigable. His twenty-hour normal work day, day in and day out, year in and year out, stood him in good stead during those exciting days. Although the defense effort took up most of his thoughts and time, Bergmann still managed to plan the expansion of scientific activities at the Weizmann Institute. When more normal scientific activity could be resumed it was again Bergmann who was the moving spirit in giving the Institute a feeling of cohesion. Bergmann would attend all seminars. Following this example, younger members of the Staff attended lectures outside their own narrow domain. In short, Bergmann succeeded in the difficult task of inculcating a sense of unity, and unity of purpose, in the ever-expanding staff. He initiated interdepartmental researches to add cohesion between workers of different disciplines running in the various departments. Bergmann continued in Weizmann Institute until his appointment to a chair of Organic Chemistry at the Hebrew University of Jerusalem in 1952. Students in the field of organic chemistry got to know that a short cut to a literature search was to address a question to him. Rather than answer directly he would dash out of the laboratory down the steps towards the library. By the time you managed to get there in his wake he would already have the volumn of the pertinent: journal open to the page which contained the answer to your question and would smilingly hand it to you. The feeling was that one was witnessing the image of his old father Rabbi Bergmann, albeit a Rabbi in organic chemistry. For many in this period, the most pleasant time of the day came between 10 P.M. and 2 A.M. or so, when the laboratory was bustling with students working alongside of Bergmann. I was told that he would then expound on everybody's work while watching a distillation connected with his own experimental work which he did not give up until much later. Bergmann's work in the fields of organic chemistry was truly enormous. He contributed substantially to a number of fields due to his wide knowledge and great imagination and dabbled in many more. It will perhaps be easier to follow some of Bergmann's chemical interests chronologically. Some of these interests range over the period of his whole scientific career. Bergmann's interest in polycyclic aromatic compounds began early in his career. His earliest papers published with

Schlenk deal with such substances and with the employment of alkali metal-organic compounds in synthesis. The mechanism of addition of sodium to double bonds was also investigated. The work was extended also to the use of lithiumand potassium-derivatives. It led Bergmann to the measurement of dipole moments for the establishment of structure, one of the earliest uses of this technique in organic chemistry. This work also led Bergmann into investigations on sodium induced polymarization. Bergmann's interest in molecular rearrangements began to appear in publications during 1935. During this period he became interested in steroids and particularly in the migration of the angular methyl group during dehydrogenation. The work on polycyclic aromatic compounds continued at the Sieff Institute. In synthesis of such compounds much use was made of the then new Diels-Alder reaction. This is one example of Bergmann's rapid application to his own work of newly discovered reactions and techniqlies. He inaugurated a number of researches on photochemical reactions some twenty five years before photochemical reactions became so fashionable. He was also one of the fi~st to invest/gate polycyclic aromatic derivatives as carcinogens. In the early fifties a fruitful collaboration with the Pullmans in Paris, and a number of eoworkers in Rehovot, resulted in an exhaustive series of theoretical and experimental papers on substituted fulvenes and fulvalenes. He also added insect chemistry and insecticides to his interests. Here, too, one is struck by the natural way in which Bergmann expanded his work from one field to another. During this decade Bergmann also began to work in various fields of biochemistry, particularly in the field of antimctabolites. However, during most of his active life his chief interest has been in fluorine chemistry and fluoro-derivatives of many important metabolic intermediates. Already in the early 50's he investigated the action of 5-fluorotryptophan on Escherichia coli, studied the preparation of a-fluorocarboxylates and pyruvates and their enolization; looked on the mechanism of poisoning by fluoroacetates and higher alkyl fluoroalkanoates; and prepared a series of fluorinated aromatic amines and trifluoroethanol derivatives. Bergmann also studied in detail the infrared spectra of fluorinated compounds especially fluoropyruvates and many condensations of fluoroacetic acid. His contribution to fluorine chemistry continued with development of many new reactions with silver fluoride, perchioryl fluoride, fluoromalonates and many types of fluoroheterocycles. The so-called Yarovenko reagent was intensely utilized in his laboratory for making novel fluoroamino acids including fluorinated mevalonic acid derivatives. Fluoropolycyclic carcinogens and fluorophosphorous compounds were also made. In the 60's Bergmann continued to work on fluoroamino acids but developed also the chemistry of fluorooxaloacetates with which he prepared a series of new compounds. Toward the end of the decade experimentation with trifluoromethyl hypofluorite had also started and several highly interesting results were recorded and published.

S. Rozen / Journal of Fluorine Chemistry 90 (1998) 157-159

With the breadth of knowledge and phenomenal memory that Bergmann had, followed by immediate applications of new data to related fields, it is not surprising to find his work cited in a large number of review articles covering many different aspects of organic chemistry. Ernst David Berg-


mann, now a legend in Israel, was the father and the Dean of Organic chemistry in this country and I would like to add a continuous inspiration for his numerous students including myself, and for a whole generation of scientists in this part of the world.