RALPH E. OESPER University of Cincinnati, Cincinnati, Ohio
W ~ ~ GLANGENBECR, A N G son of a physician, was born a t Gottingen on June 21, 1899. He early developed an interest in chemistry, largely through the influence of Dr. Hartung, his teacher a t the Gottingen Gymnasium whose classes were notable because of the well chosen and striking demonstration experiments. At the University of Gottingen, where he studied from 1919 to 1923, his teachers were Windaus, Wienhaus, Borsche, Tammann, and Pohl (physics). His Ph.D. was taken in 1932 under the direction of Windaus; the dissertation dealt with new methods for synthesizing imidazoles. The course of Langenbeck's future independent researches was laid by the scientific inspirations of the Gottingen faculty, particularly Windaus. A year as assistant a t Karlsruhe under Freudenberg and Goldschmidt was of great profit. Then followed a long stay in the United States as Rockefeller Fellow. Langenbeck worked a t Yale and then a t the Agricultural Experiment Station in New Haven, under the direction of Osborne and Mendel (1924-25). Returning to Germany, he served as assistant and later as director of the organic laboratory a t the University of Miinster (1926-35) under R. Schenck. Here he became Privatdozent in 1928, with a study of organic catalyzers as his habilitation essay. I n 1935 he was called as professor to the University of Greifswald, and in 1940 accepted a call to the Technische Hochschule in Dresden. I n 1947 he went t o Rostock where he remained until 1951 when he accepted his
uresent uost as head of the Institut a t the University of Halle. Following his initial independent researches on the constitution of pilocarpine and isopilocarpine, and the configuration of histidine, Langenbeck (since 1926) has devoted his research efforts mainly to the chemistry of organic catalysts. This field had been practically ignored in comparison with the chemistry of heterogeneous i n o r g a ~ ccatalysts. However, the catalytic action of definite organic materials has a particular interest in enzyme chemistry. In isatin, ortho-quinone, and their derivatives, he discovered materials which have dehydrase action, and similarly he found that primary amines exhibit carboxylase action along with carboligase action. By systematic substitution, the activity of such materials was enhanced almost to the enzyme action state. Such activations, combined with a raising of specificity, were attained also with hemin by addition of substituted imidazoles. These experimental studies led eventually to the "primary valence theory" of the desmolase actions, a concept which proved its value with the discovery of each new enzyme. His well known monograph "Die organischen Katalysatoren und ihre Beziehungen zu den Fermenten" appeared in 1935; the second edition was published in 1949. The latest compilation of this special field of Langenbeck's interest is contained in "Advances of Enzymology" (Volume 14, 1953). Since 1936 he and his co-workers have been studying
the technical applications of organic catalysts, particularly with regard to the synthesis of fats. I n this connection, he investigated the mechanism of the oxidation of paraffin, and demonstrated that ketonehydroperoxides are formed as the decisive intermediate stage in this oxidation. As early as 1932, he discovered the exceptionally high affinity of imidazole for hemin, a fact of great importance with respect t o the constitution of hemoglobin and other hemoproteids. The protein segment is bound t o the hemin through the imidnzole nucleus. Recently, he found that there is a steric hindrance in the formation of metal complexes. All 2- and Csubstituted imidazole derivatives were found to be sterically hindered in the addition to hemin and iron-phthalocyamin. His "Lehrbuch der organischen Chemie" was com-
posed 1936-38. It is now in its 14th edition. Through his efforts, an Institut fiir Katalyseforschung was erected in Rostock in 1949. He still serves as the director of its organic section; the inorganic section is headed by Giinther Rienacker (THIS JOURNAL, 26,666, 1949). One of Langenbeck's first discoveries in this laboratory was that of "mixed formate contacts." Mixed crystals of nickel formate and magnesium formate, after reduction in a stream of hydrogen, yield hydrogen contacts which are more active than Raney nickel. Professor Langenbeck is a member of the Deutsche Akademie der Wissenschaften in Berlin and of the Akademie der Deutschen Nat,urforscher (Leopoldina). At present, his main activity is the supervision of the erection of a large building for teaching and research in chemistry a t the University of Halle.
