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At 9 a.m. on Monday, July 5,1976, a festive session sponsored hy the Gesellschaft Deutscher Chemiker and the Faculties of Chemistry and Pharmacy of the University of Munich was held in the Liebig Lecture Auditorium of the Chemical Institute of Munich. The occasions were the onehundredth anniversary of the birth of Alfred E. Stock and the Third International Meeting on Boron Chemistry. The large demonstration table at the front of the hall was bedecked with flowers and the single element horon was illuminated on one of the large periodic charts during most of the program. Students applauded speeches by Professor 0. Glemser, President of the GDC, Professor L. Malatesta, President of the Inorganic Division of the IUPAC, and Professor H. D. Stachel, Vice President of the University of Munich, in their characteristic way by knocking on lecture desks. The Alfred Stock Memorial Medal was presented to Professor H. Noth of Munich and an honorary doctorate was conferred on Professor W. N. Lipscomb of H w a r d , who opened his lecture on "Structure and Bonding in Boron Hydrogen Compounds" with a slide containing the following quotation from Sidgwick (I) All statements about the hydrides of boron earlier than 1912, when Stwk began to work upon them,. . .are untrue. In a lecture entitled "Alfred Stock und die Renaissance der Anorganischen Chemie" Stock's famous student, Professor E. Wiberg of Munich, then recounted the tragic history of the man who was almost destroyed hy the very agency which he developed to perform the first reliable researches on borane chemistry. Alfred Stock's klentnlc Work Alfred Stock is remembered chiefly for his work during the period 191C1936 on the syntheses and reactions of the horon and silicon hydrides (2)and for the development of the Stock high vacuum apparatus which made that work possible. Stock's apparatus is of crucial importance in the history of the development of organometallic chemistry (3).He also worked in phosphorus and arsenic chemistry and contributed to our knowledge of the compounds of carbon with the oxygen group of elements. Stock was responsible for the "Stock nomenclature" in current use in which the name "ferrous chloride" is replaced by "iron (11) chloride." He was a tireless worker in educational and chemical organizations and served as President of the Deutsche Chemische Gesellschaft (since 1947 the Gesellschaft Deutscher Chemiker). I t is difficult to overstress the novelty and importance of Stock's horon hydride research. Many of the most famous chemists of the nineteenth century had attempted to make boron analogs of the hydrocarbons and failed, hampered by the primitive apparatus a t hand. Even Sir William Ramsey, whose work with the "inert" gases marked him as an adept gas manipulator, could do nothing with the system. Stock accomplished his difficult work with nothing from the theoretical or synthetic literature to guide him. His tragedy is that he unknowingly exposed himself to mercury vapor early in life and contracted the severe mercury poisoning ("Quecksilberuergiftung") which almost ended his scientific career in midstream. As Stock himself is reported (4) to have written in his diary, without that ". . . damned Mercurius and his followers.. .I chould have achieved much more in every respect. . ."
Alfred Stock devoted a laree ort ti on of his time to research on mercury from 1924 until i943, motivated by awish ". . .to warn most emphatically all who have to work with metallic mercury about the dangers of this volatile metal and to spare them the evil experiences which have s ~ o i l e dthe ereatest portion of my life. . ." (5). Stock's own hook (2)written during the period February to June 1932, while he was the George Fisher Baker Nonresident Lecturer in Chemistry a t Cornell, is the best source for information about most of his horon and silicon hydride work and the development of his high vacuum apparatus. Shortly hefore his death in 1946, Stock gave his diaries and other personal papers to Professor Wiberg, who has written a moving biography (4) which has been ahstracted twice in English (6). ~
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Stock's OuecksIlberver~Iffun# That set of symptoms chara~teristicof chronic mercurialism is called erethism (7) and was often ohsewed in workers in the felt-hat industry during that period when the "carrotting" process with its treatment of fur with mercury solutions was in use. In mild cases of mercurialism, erethism includes psychological effects such as anxiety, timidity, indecision, and lack of concentration. More severe poisoning can lead to intellectual deterioration and loss of memory. In addition, tremors.. s.~ e e c hand hearine difficulties. nerve disorders. nasal catarrh, inflammation of the mouth and gums, and loosening of the teeth are observed in seriou cases. Stock sought medical aid without success for many of these symptoms for almust a quarter of a century before his chronic ill health was finallv diagnosed correctly in 1924 as mercurialism. Alfred Stock was born on July 16, 1876, in Danzig (now Gdansk in Poland) and grew up in Berlin where his father, an insurance executive, was transferred in 1878. He was a bright student who received encouragement from one of his Gymnasium instructors, Dr. Otto Hoffman, in support of his chemical inclinations. His father overcame inward misgivings about scientific careers and also encouraged the youth by supplying him with books and apparatus for a home laboratory. Unfortunately, Stock frequently worked with mercury in his schoolbov laboratow and nrobablv nlanted there the seed of his late; hypersensitivity'to this &d. At the University of Berlin Stock chose t o work in the institute of Emil Fischer where his Ph.D. supervisor (Doktorwater) was Adolph Von Baeyer's son-in-law Oskar Piloty, destined to lose his life as a machine gun officer a t the battle of the Somme in 1915. Stock's doctoral work, done with great experimental skill, was concerned with analytical and organic chemistry, and his Ph.D. was awarded in 1899. At this time Fischer was concerned with the rebuilding of inorganic chemistry in Germany. Impressed with Stock's experimental skill, Fischer sent him to Henri Moissan's laboratory in Paris for training in inorganic chemistry. Clemens Winkler had made the lower hydrides of cerium, thorium and zirconium, in 1890-91 by mixing oxides of the metals with magnesium and heating in an atmosphere of hydrogen. At the time Stock came to him, Moissan had adapted Winkler's maenesium carrier method to his own electrical furnace and was preparing the hydrides of lithium, sodium, and calcium (8). Although Stock's work with Moissan was conrerned with Volume 54, Number 4. Aprll 1977 1 211
boron analysis and the synthesis of boron silicides, he used the magnesium curier methnd in his preparation of SbHn (9) soon after his return to Berlin and it formed the basis for his later preparation of the boron hydrides. Stock's account of his time w t h Moiwan has been translated into Enalish - bv R. E. Oesper (10). Stock returned to Fischer's institute in Berlin in 1900 and immediately set u p in a small unventilated room a mercury trough for the collection of small amounts of gases (11). This device had originally been described by Bertholet and was rediscovered bv Stock and Moissan. At this time his beadaches, dizzy spells, memory loss, and catarrh first became apparent. although the cause was unknown. In spite of these &;auks on his health, Stock's work he became academically qualified (Hobilifolion) in 1904 and wan given the title Professor in 1906, allowing him the financial independence to marry. In 1909 Stock accepted an appointment as Professor a t the Institute of Technology of Breslau in Silesia (now Wroclaw, Poland) where he had the freedom to heein his studv of the ~~~~~~~. boron hydrides. Although he had suggested the proj& some years earlier, he had been discouraged hy Fischer, who had been incontact with Ramsey. 1)uring his first year at Breslau, Stock was burdened with administrativedetails to the extent that be could not work in the laboratory and his symptoms of mercurialism abated. They became severe again, however, soon after he resumed experimentation in his laboratories where hieh vacuum svstems incorporatina many open containers oTmercury were being developed. After the events of August 1914, the number of students a t the Breslau Institute beg& to drop sharply and Stock decided t o move. Richard Willstitter (12) had been called to the University of Munich to take the place of von Baeyer, who was retiring, and Alfred Stock was offered Willstirtter's position a t the Kaiser-Wilhelm-Institutefur Chemie in Berlin-Dahlem (a suburb southwest of Berlin). Stock was not called for war service because of his chronic respiratory ailment and advancing deafness, more unrecognized symptoms of mercurialiam. He and his coworkers had to vacate their institute svace in the last years of the world war tomake space for the "militaw" Kaiser-Wilhelm-Institut of Fritz Haher and they were ted_porarily housed a t the University of Berlin. ~ u r i n those g war years, he was again exposed to mercury vapor. In the postwar years Stock tried to rid himself of his respiratory troubles with cures, baths, operations, and even mountain climbing, but to no avail. By 192S24 be had almost comnletelv lost his memorv "... so that a t that time I despaired of continuing in science . . ." (5).Finally in March 1924, one of Stock's young collaborators had a tooth abscess diagnosed by his (the collaborator's) brother, a medical doctor. as due to mercury poisoning and the cause of Stock's illness was finally discovered by the noted toxicologist Professor L. Lewin, whom Stock called in as a consultant to examine himself, his coworkers, and his laboratory spaces. After a two-month convalescence Stock began his researches into mercurv - ~- wisonine and contamination. which were to span the final 20 years of cis life. The Kaiser-Wilhelm Institutes lost their fmancial independence during the postwar inflation. In addition, Stock was anxious to continue his work in an uncontaminated building. Accordingly he accepted a call in 1926 as Professor t o the Technical Institute at Karlsmhe where he remained until his retirement in 1936. Here he designed and built mercury-free laboratories which were a model for the scientific world. Floors were covered with seamless linoleum and lab benches were bolted to the wall for efficiency in cleaning. Mercury apparatus was installed in well-ventilated hoods (13). Unfortunately Stock himself was bothered by mercury even in his ultraclean laboratories, having developed hypersensitivity to that metal. He held committee meetings by open windows (in the winter foot warmers were provided for less hardy colleagues). When his office was found to be contaminated by mercury he moved ~
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his literature work t o the terrace. Mischievous rumors, prohably started by victims of his open window policy, had i t that his catarrh resulted more from his methods of combating mercury poisoning than from mercury itself, but Wibera tells us that this is not so: Stock's "Quecksilberuergiftung" was quite real (14). In spite of his suffering from and fear of mercury, Stock used himself as an experimental subject, describing his own physiological reactions when he treated his nasal cavity with a dilute solution of mercurv(l1) chloride (1.5). By 1936 Stock's health l k d deteriorated so badly that he reauested emeritus status. He moved to Berlin in Sevtember of i936 where he was given the responsibility of continuing his mercury research in a small laboratory located in the Dahlem Division of the government health bureau (Reichsgesundheitsamt). In a grim replay of history, he was moved in October 1939into the Kaiser-Wilhelm Institute for Physical Chemistry in Berlin-Dahlem-into two small laboratories which were found to be strongly mercury contaminated. Stock wound up his research work in May 1943, when even his small mercu&infested laboratories were required for war work. Four months later he leased his bomb damaged house in Dahlem to the government past office to provide shelter for bombed-out officials and moved in with his brother-in-law in Bad Warmhrunn. Stock and his wife became refueees in the confusion of February 1945, and made a trip across~ermany which must have been filled with hardshivs and vain, . . considering his physical condition. Although they were trying t o join Stock's daughter-a biologist in Hechingen where the Kaiser-Wilhelm Institute for Biology had been moved in 1943-the condition of the railroads forced them to end their journey in Dejsau. In March 1945 their hotel in Dessau was homhed, destroyina most of Stock's possessions, but Stock's 3 Emst old friend and c&borator during t h A g l ~ l 9 2 period, Kuss. found a d a c e for them nearby in a magnesium workers' of ken. Soon afterwards barracks in thesmall Elbe river &t Aken was occuvied fust by American, then British, and f d y Russian troops.'l'he ~ t o c k were s displaced from the barracks, but finally found r~.fugewith a family nearby. Here Stock died early in
