| Photo Credit: James S. Lipscomb
William Nunn Lipscomb, Jr., an emeritus professor at Harvard University who won the Nobel Prize in chemistry in 1976 for work on chemical bonding, passed away in April at age 91.
Lipscomb was born on December 9, 1919, in Cleveland, Ohio. He became interested in chemistry at a young age and assembled a laboratory in his bedroom, where he made things like fireworks and stink bombs. He attended the University of Kentucky on a clarinet scholarship and graduated with a bachelor’s degree in chemistry in 1941. He then enrolled in graduate school at the California Institute of Technology, intending to study physics, but he switched to physical chemistry after a year to work with Linus Pauling.
As part of the wartime effort, Lipscomb worked for the National Defense Research Council during the day and on his doctoral research at night. He graduated in 1946 and became an assistant professor at the University of Minnesota, where he remained until 1959, when he moved to Harvard University to become a professor of chemistry. Lipscomb remained at Harvard for the rest of his career, becoming the Abbott and James Lawrence professor of chemistry in 1971 and the Abbott and James Lawrence professor of chemistry emeritus in 1990.
Lipscomb’s research centered on three areas: nuclear magnetic resonance and chemical shifts, boron chemistry and the nature of the chemical bond, and large biochemical molecules.
He used NMR to investigate carboranes (clusters of boron and hydrogen shaped like polyhedra) and the sites of electrophilic attack on these compounds. This work led to his publication of a comprehensive theory of chemical shifts, and he provided the first accurate values for the constants that describe the behavior of several types of molecules in magnetic or electric fields.
Lipscomb deduced the molecular structures of numerous boranes (compounds made of boron and hydrogen) and their derivatives using X-ray crystallography in the 1950s. Since the stability of boranes could not be explained by traditional concepts of electron bonding, he developed new X-ray techniques that showed how a pair of electrons could be shared by three atoms. He later applied these techniques to carboranes. The work formed the experimental basis for the extended Hückel theory, the first widely applicable use of molecular orbital theory to study chemical bonding, and also earned him the 1976 Nobel Prize in chemistry.
Lipscomb’s later research focused on the atomic structure of proteins and how enzymes work. He used X-ray diffraction to solve the three-dimensional structures of carboxypeptidase A, aspartate carbamoyltransferase, leucine aminopeptidase, HaeIII methyltransferase convalently complexed to DNA, human interferon beta, chorismate mutase and fructose-1,6-bisphosphatase. Lipscomb’s group also contributed to an understanding of concanavalin A, glucagon and carbonic anhydrase.