George S. Hammond
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| George S. Hammond | |
|---|---|
| Name | George S. Hammond |
| Birth date | 22 May 1921 |
| Birth place | Portland, Maine, U.S. |
| Death date | 5 October 2005 |
| Death place | Portland, Oregon, U.S. |
| Fields | Physical chemistry, Organic chemistry |
| Workplaces | Iowa State University, California Institute of Technology, University of California, Santa Cruz |
| Alma mater | Bates College, Harvard University |
| Doctoral advisor | Paul D. Bartlett |
| Known for | Hammond's postulate, Photochemistry |
| Awards | American Chemical Society Award in Pure Chemistry (1956), William H. Nichols Medal (1968), James Flack Norris Award in Physical Organic Chemistry (1981) |
George S. Hammond. An influential American chemist whose work bridged the fields of physical chemistry and organic chemistry. He is best known for formulating Hammond's postulate, a foundational concept in physical organic chemistry that relates transition state structure to reaction coordinates. His extensive research in photochemistry and reaction mechanisms earned him widespread recognition and several prestigious awards.
Early life and education
Born in Portland, Maine, he completed his undergraduate studies at Bates College, earning a Bachelor of Science degree. He then pursued graduate work at Harvard University under the supervision of renowned chemist Paul D. Bartlett. His doctoral research focused on the mechanisms of organic reactions, laying the groundwork for his future theoretical contributions. After receiving his Ph.D. in 1947, he conducted postdoctoral research at the University of Minnesota with another prominent figure, Richard E. Heckert.
Academic career
His academic career began at Iowa State University, where he rose to the rank of professor and conducted significant early research. In 1958, he moved to the California Institute of Technology (Caltech), joining a distinguished faculty that included Linus Pauling and John D. Roberts. At Caltech, he served as the chairman of the Division of Chemistry and Chemical Engineering and further developed his theories on reaction mechanisms. He concluded his formal academic career as a professor and provost at the University of California, Santa Cruz, helping to shape its scientific programs.
Hammond's postulate
He introduced the influential principle now known as Hammond's postulate (or the Hammond-Leffler postulate) in a 1955 paper published in the Journal of the American Chemical Society. The postulate states that for a consecutive reaction, the structure of the transition state most closely resembles the species (reactant or product) to which it is closest in energy. This insight provides a powerful qualitative tool for predicting how changes in molecular structure or reaction conditions affect the nature of transition states, profoundly impacting the study of reaction kinetics and stereochemistry.
Research and contributions
Beyond his famous postulate, his research program was broad and innovative. He made pioneering contributions to the field of photochemistry, investigating the behavior of molecules in excited states. He studied triplet states, energy transfer, and the photodimerization of anthracene. His work provided fundamental insights into photosynthesis and the development of solar energy conversion technologies. He also authored a highly influential textbook, Organic Chemistry, with his Caltech colleague David J. Cram.
Awards and honors
His scientific achievements were recognized with numerous accolades throughout his career. He received the American Chemical Society Award in Pure Chemistry in 1956. Later honors included the William H. Nichols Medal from the American Chemical Society in 1968 and the James Flack Norris Award in Physical Organic Chemistry in 1981. He was elected a fellow of the American Academy of Arts and Sciences and a member of the National Academy of Sciences, one of the highest honors for an American scientist.
Personal life and legacy
He was married to Dorothy "Dottie" Hammond, and the couple had three children. After retiring, he remained active, consulting for the 3M Corporation and enjoying pursuits like fly fishing. He passed away in Portland, Oregon in 2005. His legacy endures primarily through Hammond's postulate, a cornerstone of modern chemistry taught worldwide, and through his many students who became leaders in academia and industry.
Category:American chemists Category:1921 births Category:2005 deaths Category:Physical organic chemists