In memory of Professor Andrew Streitwieser, Jr.

The California Section lost one of its best known figures with the death of Professor Andrew Streitwieser, Jr. on February 23rd, 2022, at the age of 94.  As a graduate student with Professor William von Eggers Doering at Columbia University, Streitwieser studied the mechanisms of organic reactions that occur via reactive carbocation intermediates, and became interested in predicting their stability using a relatively new theoretical approach, molecular orbital theory.  Theoretical calculations of any kind were still essentially manual procedures in 1950, as Professor Streitwieser describes in his memoir on the quantum chemistry history web site.

Streitwieser continued this work as a postdoc with Professor John D. Roberts at MIT before joining the faculty at the University of California, Berkeley, in 1953, where he taught and advised students continuously until just a few years ago.  Professor Bergman kindly submitted the following recollections that describe the broad influence of Professor Streitwieser’s work.  Professor Streitwieser’s 1985 organic chemistry textbook (coauthored with Professor Clayton Heathcock) was an essential reference for me during my career as chemist in the life sciences industry.  I finally met Professor Streitwieser in 2007 when the California Section recognized him as 60-year member of the ACS. -Alex Madonik

Recollections of Professor Andrew Streitwieser, Jr.

by Professor Robert Bergman, UC Berkeley

Andrew Streitwieser was a major figure in the field of physical organic chemistry and was one of the earliest contributors to applying and concepts of physical and theoretical chemistry to organic chemistry, A notable area of study of his involved the inspection of organic compound intermediates called carbocations, or “short-lived” compounds that would form as a result of organic reactions.  His textbook on Solvolytic Displacement Reactions was purchased and read by most organic chemists with an interest in mechanisms, and his book on Molecular Orbital Theory for Organic Chemists brought understanding and utility to a wide range of workers in the field.  Another major contribution was his understanding and application of kinetic isotope effects to the study of reaction mechanisms, which made him a leader in that area of physical organic chemistry as well. 

Andy was also a dedicated teacher.  He and Clayton Heathcock were well known for their ground-breaking undergraduate organic textbook, and I learned a lot from him during the several years that he and I co-taught the first year graduate physical organic course at Berkeley.

One of Andy’s insights that most impressed me was his prediction and discovery of the sandwich compound uranocene.  Once the structure of ferrocene had been elucidated, Andy’s analysis of the molecular orbital structure of that molecule, and his deep understanding of how MO theory could be used, led him to predict that a similar sandwich compound, but in this case using an actinide and eight-membered pi systems (rather than transition metals and five-membered pi systems that formed ferrocene) should be stable.  In what I think was a triumph of that way of thinking led him and his group member Ulrich Mueller-Westerhoff to synthesize uranocene and demonstrate that it is, in fact, quite stable.  This was a time when most organic chemists paid little attention to molecules that had metals in them.

Later in his life Andy focused his research on the acidity of organic compounds, and developed one of the most often used methods for measuring quantitatively the pKa’s of organic acids that were weaker acids than water, so that their acidity had to be measured in less protic solvents.  This required careful experimental work carried out on equipment that was rigorously air- and water-free.

Besides his scientific contributions, Andy was a kind and friendly man personally. He was one of the people who attracted me to Berkeley in the late 1970’s, and he was always available to answer my questions on the many occasions I found myself confronting a thorny mechanistic problem.  He was one of my favorite colleagues and I will miss him greatly.

Comments by Jonathan L. Sessler,

Doherty-Welch Chair, The University of Texas at Austin

Andy Streitwieser was a household name—literally—well before I had the privilege of having him as an instructor as an undergraduate at Cal in the 1970s. He and my father, Andy Sessler, both hailed from Jamica, NY and both were finalists in the 1945 Westinghouse Science Talent Search. That brought them both to the White House as honorees. While they were apparently close in their youth, they were not by the time they were both at Berkeley in the 1960s and 1970s. Nevertheless, my father, a physicist and during my college years, Director of the Lawrence Berkeley Laboratory (now referred to as LBNL), admired Andy Streitwieser greatly. He was held up in our home as a paragon of chemical excellence. I was made all too aware as a youngster starting to show interest in chemistry, that as a high schooler Andy Streitwieser had already published in the prestigious J. Am. Chem. Soc. (“Chlorination of Fluorene with Sulfuryl Chloride,” J. Am. Chem. Soc. 1944, 66, 2127; DOI: 10.1021/ja01240a507). At a comparable age, I was still dabbling in the home lab making esters, such as ethyl butyrate. (For the non-chemist, ethyl butyrate has a pineapple-like smell but hydrolyzes to give butyric acid that smells like vomit; hence the perfect choice to spike my younger sister’s perfume.) Fun, but no where near the level of the Andy Streitwieser.

Thus, it was with great anticipation and some degree of hero worship that I enrolled in Andy Streitwieser’s major’s section of sophomore organic chemistry. He did not disappoint. We were treated both to massive draft copies of the emerging (at the time) Streitwieser-Heathcock textbook and lectures that fabulous in their clarity and ability to inculcate enthusiasm for the topic. My friends and I at the time were into it, to use Berkeley-speak, and printed up T-shirts with various Molecules of the Day. Looking back, it is not surprising, but at the time we were all terribly impressed that Andy Streitwieser could recognize each with a glance and would egg us on with comments like, “You know that structure is wrong?” “No, really?” “Yes, you forgot the stereochemistry!” The occasional jokes aside, the course was face-paced, rigorous, and inspirational. No surprise that as a senior I enrolled in Andy Streitwieser’s physical organic chemistry class. At the end of that 1-quarter course, I was hooked. I left Cal with a life-long love of physical organic chemistry and deep appreciation for the power of thinking in molecular orbital terms. Andy Streitwieser was a great teacher—and to me as a high schooler interested in chemistry and then a Cal undergraduate, much, much more.

Here’s what the Daily California had to say:

UC Berkeley professor emeritus of chemistry Andrew Streitwieser dies at 94


The campus College of Chemistry Dean Douglas Clark announced the passing of professor emeritus Andrew Streitwieser in a letter to the campus community Feb. 24.

Streitwieser was a “major figure” in the field of physical and organic chemistry and was one of the earliest contributors to applying physical techniques to organic chemistry, according to Robert Bergman, the Gerald E. K. Branch distinguished professor emeritus of chemistry. A notable area of study of his involved the inspection of organic compound intermediates called carbocations, or “short-lived” compounds that would form as a result of organic reactions, according to Bergman.

“He was working at a time when most organic chemists were focused almost exclusively on organic compounds,” Bergman said. “There was little attention given by organic chemists to compounds with metals in them. Andy bridged that gap in a very interesting way.”

According to the letter, Streitwieser was a “pioneer” in the study of molecular orbital theory. In collaboration with colleagues, Streitwieser authored “Molecular Orbital Theory for Organic Chemists,” which Bergman regarded as one of the “most important and groundbreaking” textbooks in organic chemistry.

“It was a higher-level textbook, but still did very well in the market,” Bergman said. “It brought mechanistic chemistry into the undergraduate level and had a major impact on how organic chemistry was taught

Streitwieser was born in Buffalo, New York, in 1927, and studied at Columbia College and Columbia University to earn his Ph.D. in 1952, according to Clark’s letter. The letter noted that after working as a postdoctoral fellow at the Massachusetts Institute of Technology, Streitwieser moved to campus as a professor of chemistry in 1952 and retired from the College of Chemistry in 1993, yet still remained active in the department post-departure.

Streitwieser received numerous accolades throughout his career, including the Alexander von Humboldt Medal and the ACS Cope Scholar Award, as well as membership in organizations such as the National Academy of Sciences and the American Association for the Advancement of Science, according to Clark’s letter.

Besides Streitwieser’s major accomplishments, Bergman said others will remember him as a personable, nice individual, and that he was a respected professor, one that was admired by his graduate and postdoctoral students alike.
“His graduate and postdoctoral fellows never had a bad word to say about their interaction with him. He helped them learn and helped them get jobs after they graduated,” Bergman said. “They have great respect for him, even long after leaving Berkeley.”