A marvelous fox: William Lipscomb (1919-2011)

Since we were speaking of chemical hedgehogs and foxes the other day, here's a remarkable fox who we forgot to mention, and it's unfortunate that I was reminded of him by his obituary.

William Lipscomb undoubtedly belongs at the top of the fox list. Lipscomb who was a Kentucky Colonel (along with Robert Grubbs) started his academic career at the University of Kentucky on a clarinet scholarship. He then got his PhD with Linus Pauling at Caltech and followed his mentor in exploring diverse chemical worlds. A Harvard professor for almost his entire career, he was an extraordinarily versatile chemist who made important contributions to at least two disparate fields (crystallography and theoretical chemistry) and trained students who themselves achieved fame. As one measure of his versatility and influence, consider this: his student Roald Hoffmann who studied quantum chemistry (more specifically extended Hückel theory) with him won the Nobel Prize in 1981 for formulating the Woodward-Hoffmann rules while his student Tom Steitz who studied protein structure with him won the prize in 2009 for his illumination of ribosome structure.

Lipscomb is best-known for unraveling the strange, electron deficient structure of the boranes. In diborane, there don't seem to be enough electrons to go around and the quintessential bonding feature is a so-called shared '3-center 2-electron bond'. The gifted English theoretical chemist Christopher Longuet-Higgins had made a foray into explaining the unusual bonding in such molecules, and Lipscomb was instrumental in experimentally determining the structure of these compounds and extending the theoretical framework. At first an anomaly dotting the landscape of respectable chemical bonds, the bridging boron-hydrogen-boron bond is now accepted not only as a mainstay of bonding in the diverse family of boranes but as a prototype for similar bonding in countless other molecules, most notably in carbocations. Lipscomb's work along with that of Longuet-Higgins and others brought multicenter bonds to the masses.

Bonding in boron would have been enough to bring Lipscomb a Nobel Prize but his imaginative thirst was not slaked. He made key contributions to a very different field which were at least as important as his boron excursions. Lipscomb became a pioneer in protein structure determination. His structure of carboxypeptidase was at the time bigger than anything solved until then and provided important insights into peptide-bond cleavage. Later his group contributed to the solution of the structures of a variety of pharmaceutically important enzymes and proteins, such as aspartate carbamoyltransferase which performs the first step in the important biosynthesis of pyrimidines. It's not surprising that Lipscomb's student Tom Steitz was honored for similar crystallographic contributions.

In addition, Lipscomb had a great sense of humor; he was a fixture at the annual IgNobel Prize ceremony held at Harvard and is perhaps the only famous chemist featured in a YouTube video on how to tie a string tie. For me, another memorable Lipscomb fact was his incisive quote about the difference between chemistry and physics that drove home the limitations of reductionism as applied to chemical concepts.

Being a rare expert of the highest order in the diverse fields of protein crystallography and theoretical chemistry, hosting the annals of improbable research, winning a Nobel Prize while mentoring other Nobel laureates, and bringing string-tie tying to the masses- Bill Lipscomb did it all. We are indebted to him for showing us how a real fox should be.

Update: Chembark has some nice personal recollections.