Fukui, Kenichi

▪ 1999

      Japanese theoretical chemist (b. Oct. 4, 1918, Nara, Japan—Jan. 9, 1998, Kyoto, Japan), applied a variety of concepts in physics to research that revolutionized the understanding of how chemical reactions take place. His work was based on a mathematical analysis of the actions of electrons as they are exchanged between atoms and molecules during a chemical reaction. Applying principles of quantum physics and using related mathematical treatments, he analyzed the properties that these electrons exhibit during and after reactions. Fukui theorized that in many chemical reactions it is the electrons in the outer orbitals—those regions of space occupied by electrons farthest from the atomic nuclei—that determine the pathway of the reaction and its final products. To the crucial configurations in which electrons in these outer orbitals participate during reactions, Fukui gave the name frontier orbitals. Although he had first set forth his theory in a 1952 paper and went on to publish more than 270 papers on frontier orbitals, his work received little initial notice, owing to the obscurity of the English-language journals that carried most of his papers and the extremely complex nature of his calculations. He and Roald Hoffmann shared the 1981 Nobel Prize for Chemistry for their independent work on the theoretical analysis of chemical reactions. Fukui's theories have enabled scientists to predict chemical reaction pathways more precisely and have led to many advances in the pharmaceutical and chemical-synthesis industries. Fukui was awarded (1948) a doctorate from Kyoto University, where he served as a professor of physical chemistry (1951-82). He was the president of the Kyoto Institute of Technology from 1982 to 1988. In 1981 Fukui was elected a foreign associate of the U.S. National Academy of Sciences, and he was also the recipient of the Japanese Order of Culture.

* * *