The Non-classical Cation: A Classic Case of Conflict

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Chemistry World has published an article highlighting Saul Winstein, Herbert Brown, and George Olah’s debates regarding the non-classical cation and its legacy on the field of chemistry.

“These battles of will help to give chemistry its vitality, able to argue through its problems with all the verve of a fractious family” (Excerpt from “The Nonclassical Cation: A Classic Case of Conflict”)

“The Nonclassical Cation: A Classic Case of Conflict,” written by Mark Peplow describes the history of the controversy and debates between the late Saul Winstein of UCLA Chemistry & Biochemistry, the late Nobel Laureate Herbert C. Brown of Purdue University, and Nobel Laureate George A. Olah of University of Southern California. Peplow highlights Winstein’s idea of a ‘non-classical’ cation in 1949, which grew in popularity during the 1950s, then onto Brown’s campaign against it in the 1960s, and finally, Olah’s NMR studies supporting Winstein in the 1980s.  

Winstein Portrait Brown Olah Postcard
Saul Winstein (left), Herbert C. Brown (middle) and George A. Olah (right)

Ultimately, the article declares “[e]veryone a winner” and reflects on the impact of this great debate and the lasting legacy it has left on the field of chemistry. The full article can be found at Chemistry World.

Biography of Saul Winstein:

Saul Winstein was born in 1912 and came to the United States in 1923. He graduated from UCLA in 1934 and received his Ph.D. from Cal Tech in 1938. After a year at Harvard with Paul Bartlett, he became an Instructor at IIT and returned to UCLA as Instructor in 1941. He became Full Professor in 1947. His career flourished at UCLA until his death in 1969.

His work contributed mightily to the maturing of physical organic chemistry. His discoveries of neighboring group involvement in cation formation became integral part of the science. He conceived of the non-classical cation and the concepts of homoconjugation and homoaromaticity.

He made important discoveries in medium effects, radical and organometallic reaction mechanisms, ion-pair behavior, and mechanisms of substitution and elimination reactions. He invented many phrases such as “neighboring group participation,” “solvent=participation,” “internal return,” “anchimeric assistance,” “intimate ion pair,” “ion-pair return,” “bridged ions,” “nonclassical ions,” and “homoaromaticity.

When he joined UCLA, his desire to “understand everything thoroughly” led him into cross examinations of research ideas and results, and the famous Thursday night “Winstein Seminars.”

Recognition of Saul Winstein’s research accomplishments included the ACS Award in Pure Chemistry, 1948, membership in the National Academy of Sciences, 1955, the California Museum of Science and Industry’s California Scientist of the Year Award, 1962, membership in the American Academy of Arts and Sciences, 1966, the ACS Norris Award in Physical Organic Chemistry, 1967, and the Franklin Memorial Award for Outstanding Contributions to Chemistry, 1968.

Irving Stone, renown author of Lust for Life and The Agony and the Ecstasy, among other books, said of Saul Winstein at the memorial service: “I think this was a fortunate man, a man who realized his dream with nothing to go on but brains, character, integrity and self-discipline. On three simple terms-fulfillment, a gentle man, and a man who gave himself both to love of his family and friends, and to his work-I can say how truly wonderful that he was born, that he grew among us, that we had him for our co-worker and for our friend.

A biographical memoir of Saul Winstein, written by William G. Young (whom Young Hall is named after) and Donald J. Cram (1987 Nobel Laureate) for the National Academy of Sciences can be read here.