Bamberger, Eugen

(b. Berlin Prussia, 19 July 1857; d. Ponte Tresa, Switzerland, 10 December 1932)

chemistry.

In 1875 Bamberger entered the University of Breslau as a medical student. The next summer he studied at Heidelberg with Robert Bunsen. He later returned to Berlin, worked with Carl Liebermann, and completed his degree under A. W. Hofmann. He then became an assistent to karl Rammelsberg at the Technische Hochschule of Brelin-Charlottenburg. In 1883 Bamberger went to Munich as Baeyer’s assistant, first in the analystic, then in the organic, laboratary. He gave his inaugural lecture in 1885 and in 1891 became extraordinary professor of organic chemistry. In 1893 he accepted a professorship at the Eidgenössische Technische Hochschule in Zurich. He relinquished this position in 1905, however, because of a nervous condition that left his right arm paralyzed. He nevertheless continued private research with the aid of an assistant.

In his dissertation Bamberger worked on derivatives of guanine, then turned to similar substances. He investigated aromatic hydrocarbons and elucidated the structures of retene, chrysene, pyrene, and the glycoside picein. As he pursued his work with naphthalene derivatives, he noticed that some compounds in which hydrogen had been added to the substituted ring no longer retained their aromatic properties. He called these alicyclic because they behaved like aliphatic compounds but had a closed-ring structure. In connection with this work he also extended the centric formula of benzene to naphthalenc and supported this view with his work on benzimidazole and isoquinolinc. Turning to by-products of reactions previously studied, Bamberger examined such mixed nitrogen compounds as the hydrazones and formaryl derivastives. He then directed his attention to organic nitrogen compounds, and discovered the isodiazo compounds. He found that, unlike normal diazo compounds, in the isodiazo compounds the NO could be oxidized to NO₂. This led Bamberger to believe that a formula similar to that of nitrosamines could be used to represent those isodiazo compounds which on hydrolysis yielded normal diazo compounds. In 1894 this view was sharply criticized by Arthur Hantzsch. He suggested that the differences between the two types of diazo compounds could be explained by isomerism. As a classical organic chemist, Bamberger countered most of Hantzsch’s arguments by studying the chemical activity of the supposed isomer, but he admitted the cogency of the physicochemical arguments by replacing his proposed formula with one containing the phenylazo radical. The controversy continued for years, and only with the rejection of pentavalent nitrogen could a new formula for diazo compounds be proposed.

Bamberger then turned to the oxidation and reduction of nitrogen compounds. He reduced nitrobenzene to nitrosobenzene and phenylhydrozylamine with zinc dust in a neutral solution, but refused to patent the process. His preparation of dimethylaniline oxide supported the idea of the pentavalence of nitrogen. Following the diazo controversy Bamberger paid more attention to physical properties, investigating the optical properties of anthranil derivatives and the photochemical properties of benzaldehyde derivatives. In spite of this, however, he remained a classical organic chemist devoted to theory. He investigated natural compounds, using minimum material and the simplest equipment, and studied all byproducts thoroughly.

BIBLIOGRAPHY

1. Original Workers.“ORIGINAL. WORKS. An extensive list of Bamberger’s works is in Poggendorfi. Among his writings are “Ueber die Constitution des Acenaphtens and der Naphthalsaure,” in Bericht der Deutschen c/temischen Gesellschaft, 20 (1887), 237-244, written with Max Philip; “Ueber a-tetrahydronaphtylene,” ibid., 21 (1888), 1786-1795, 1892-1904, written with Max Althausse; “Ueber Aethyl-a-naphtylamin,” ibid., 27 (1894), 2469-2472, written with Carl Goldschmidt: “Zur Kenntnis des Diazotirungsprocess,” ibid., 1948-1953: “Ueber das Phenylhvdrozylamin.” ibid., 1548-1557: “Ueber die Reduction der Nitroverbindungen.” ibid., 1347-1350; “Ueber die Stereoisomeren’ Diazoamidverbindungen von A. Hantzsch,” ibid., 2596-2601; “Weiteres uber Diazo- and Isodiazoverbindungen,” ibid., 914-917; and “Zur Geschichte der Diazoniumsalze,” ibid., 32 (1899), 2043-2046,3633-3635.”

II. Secondary Litterature. Works dealing with Bamberger are “E. Bamberger zurn 75. Geburtstag,” in Zeitschrift fur angewandte Chemie, 45 (1932), 514; Louis Blangey, “Eugene Bamberger,” in Helvetica chimica acta, 16 (1933), 644-676: and Eduard Hjelt, Geschichte der organischen Chemie von altester Zeit bis zur Gegenwart (Bruns-wick, 1916). J. R. Partington, A History of Chemistrv, TV (London, 1964), discusses Bamberger’s contributions to organic chemistry on pp. 840-842 and gives an account of the controversy with Hantzsch under “Hantzsch,” pp.842-847.”

Ruth Anne Gienapp