Sponsored by the F. Albert Cotton Endowment Fund
Larry G. Sneddon got into boron chemistry for the adventure. In graduate school, he joined a research group investigating volatile boron compounds as possible high-energy fuels. He was attracted to the idea of working with tricky air-sensitive compounds that sometimes exploded. “I was drawn to the fact that it was hard to do and that polyboron compounds were exotic materials that other people didn’t know a lot about,” Sneddon says.
After picking up the boron bug in graduate school, Sneddon spent his career developing new methods to synthesize and functionalize boron compounds, often with applications in materials and energy sciences. His work “has constantly evidenced a vision for how fundamental boron chemistry can apply to practical problems,” says organometallic chemist John F. Hartwig of the University of California, Berkeley.
Much of Sneddon’s research has stemmed from his early groundbreaking work on metal-catalyzed polyborane reactions. By the early 1980s, chemists were regularly using transition-metal catalysts to nudge stubborn organic transformations forward or to enhance selectivity, but no one had tried the approach on boron compounds. Starting with iridium catalysts, Sneddon found ways to activate boron-hydrogen bonds, inserting organic groups such as olefins or alkynes. Before Sneddon’s catalytic work, many of these important polyborane transformations were impossible.
One of his major applications for these synthetic tools has been the design and synthesis of new boron polymers that serve as precursors for ceramics, such as boron carbide and boron nitride. Ceramics have applications as aerospace materials because they maintain their strength at high temperatures. However, conventional ceramic synthesis methods limit the possible end shapes of the materials. Sneddon developed boron polymers to expand the range of shapes ceramics could adopt. He found that he could process the boron polymers into forms such as fibers, films, or nanostructures, and then heat the materials to high temperatures to convert them into ceramics while maintaining the polymers’ shapes.
More recently, Sneddon has used his boron expertise to work on hydrogen storage materials for fuel-cell applications. One potential storage material is ammonia borane because of its high weight percent of hydrogen. Sneddon’s team has developed new ways to release that hydrogen rapidly in high yields. Most important, they demonstrated that dissolving the solid into ionic liquids accelerates hydrogen release by promoting the formation of an unstable, ionic form of ammonia borane.
These three seminal contributions exemplify Sneddon’s remarkable career, says Andrew S. Weller, an inorganic chemist at Oxford University. “He is undoubtedly one of the most outstanding boron chemists of the last 50 years.”
Sneddon, 67, received a bachelor’s degree from Centenary College of Louisiana in 1967 and a Ph.D. from Indiana University in 1971. He then completed two postdoctoral fellowships, one at the University of Virginia in 1973 and another at Massachusetts Institute of Technology in 1974. Since then, Sneddon has been a member of the chemistry department at the University of Pennsylvania. He was the chair of the department from 2002 to 2005 and became the Blanchard Professor of Chemistry in 2007.
Sneddon will present his award address before the Division of Inorganic Chemistry.