Prof. Emeritus Jack Halpern, widely recognized for his pioneering and influential contributions to the field of inorganic chemistry, died Jan. 31. He was 93.
The Louis Block Distinguished Service Professor Emeritus of Chemistry, Halpern made seminal contributions to the field, particularly his research on catalysts—the magic agents that speed up chemical reactions. He helped usher in the flowering of catalysis chemistry in the latter half of the 20th century, crucial for manufacturing everything from pharmaceuticals to adhesives. His work to decode the mechanics of chemical reactions underlies many modern chemical manufacturing processes.
“He was a towering intellect,” said Prof. Viresh Rawal, who chairs the University’s Department of Chemistry. “Many chemical reaction pathways are highly complex, involving one or more transient intermediates on the way to the final products. Jack, with his very deep understanding of kinetics and reaction mechanisms, carried out careful experiments to unravel those pathways.”
Born in Poland in 1925, Halpern moved to Canada with his family at a young age, where he received his BSc and PhD degrees in chemistry from McGill University in Montreal. After stints in Manchester and Vancouver, in 1962 he joined the faculty at UChicago, where he would remain for the rest of his career.
Halpern’s work focused on understanding the fundamental chemistry of transition metals—the compounds they form and the reactions they undergo. By fully understanding these processes, researchers can tinker with the reactions to yield the exact form of the compound that they wish to produce. For example, when pharmaceutical companies make drugs, they often need the molecule to come out with the right chirality (a right- or left-flipped mirror version of the molecule) or else the drug won’t be effective.
“Jack was the preeminent mechanistic inorganic chemist of the 20th century—a real pioneer,” said Richard Jordan, the Paul Snowden Russell Distinguished Service Professor of Chemistry. “He was an unbelievably rigorous scientist, known for studying his systems in great detail and providing very strong evidence for his conclusions. He also had incredible command of the field; whenever you went to ask him about some new research, he would refer you to some experiment done in 1978 that gave you a broader perspective on your work.”
Within the department, chemistry faculty sometimes refer to the “Halpern theorem”: that just because a chemist can isolate a chemical intermediate thought to be part of the reaction pathway, it does not mean that it is a primary actor in the reaction. “Jack demonstrated this principle through his work, and it is now widely accepted,” Rawal said.
Another contribution was his quantitative measurements of bond energies—laying out the relationships between bonds of various types in chemical reactions, and thus how likely they are to form under various circumstances. For example, he studied the bonds that form during reactions with vitamin B12, which teased out how the vitamin works.
“When I think of the University of Chicago, Jack is the type of scholar who I think of as emblematic,” said Chuan He, the John T. Wilson Distinguished Service Professor in Chemistry, Biochemistry and Molecular Biology, who once shared an office suite with Halpern. “He was a pure scholar; not flashy, just a deep understanding and knowledge of the field. Whenever someone came to give a seminar in our department, after they finished giving their talk, Jack’s hand would go up and the speaker would get visibly nervous, knowing a very thoughtful and difficult question was coming their way.”
Halpern worked extensively as an editor of scientific journals, first with the Journal of the American Chemical Society and then for the National Academy of Sciences, where he served as vice president from 1993 to 2001 and as an associate editor of the Proceedings of the National Academy of Sciences for many years.
His honors include the Willard Gibbs Medal of the American Chemical Society, the Paracelsus Prize of the Swiss Chemical Society and the Robert A. Welch Award in Chemistry. He was a member of the Royal Society of London, the Royal Society of Canada, the American Academy of Arts and Sciences and National Academy of Sciences, among others. He also consulted for Monsanto and worked with Argonne National Laboratory.
His children said that his passion for chemistry was matched by his and his late wife Helen’s passion for the arts; he served on the board of directors of the University of Chicago’s Court Theatre and Smart Museum of Art for many years. The pair collected 20th-century art, particularly cubism, expressionism and surrealism.
Halpern is survived by daughters, Janice and Nina; grandchildren, Jared Henry and Claire Henry; great grandchild, Andrew Henry; brother, Norman; and many nieces and nephews. In lieu of flowers, donations can be made to the Court Theatre, the Smart Museum of Art or Doctors Without Borders.