C. Frederick Koelsch

Charles Frederick Koelsch
Born(1907-01-31)January 31, 1907
Boise, Idaho
DiedDecember 24, 1999(1999-12-24) (aged 92)
Rochester, Minnesota
Scientific career
FieldsOrganic chemistry, synthetic chemistry
InstitutionsUniversity of Minnesota
Doctoral advisorSamuel M. McElvain
Notable studentsVirgil Boekelheide

Charles Frederick Koelsch (31 January 1907 - 24 December 1999) was an American organic chemist who spent his faculty career at the University of Minnesota.[1][2][3]

Education and academic career

Koelsch was born in Boise, Idaho in 1907 in a family of German descent.[3] He attended the University of Wisconsin and earned his bachelor's degree in 1928 and his Ph.D. from the same institution in 1931, working under the supervision of Samuel M. McElvain.[2][3] After a postdoctoral fellowship at Harvard University with Elmer Peter Kohler, Koelsch was recommended for a position at the University of Minnesota by Lee Irvin Smith.[3] He joined the faculty there as an instructor in 1932 and became an assistant professor in 1934. Koelsch was awarded the ACS Award in Pure Chemistry in 1934.[3][2] He advanced to associate professor in 1937 and full professor in 1946.[1] He remained at the University of Minnesota until his retirement, assuming professor emeritus status, in 1973.[1][3] Through much of his academic career, Koelsch also served as an industry consultant, working first with Smith, Kline & French and later with Sterling Drug and Union Carbide.[3]

Chemical structure of the Koelsch radical

During his work at Harvard, Koelsch attempted to publish a paper describing an unusually stable radical compound, but it was rejected at the time on the grounds that the compound's properties were unlikely to describe a radical. Subsequent experimental evidence and quantum mechanics calculations suggested his interpretation of the original experiment was correct, resulting in the publication of the paper nearly 25 years after the original experiments.[3][4] The compound - 1,3-bisdiphenylene-2-phenylallyl (BDPA) - is now often referred to as the "Koelsch radical".[5][6]

Personal life

Koelsch married his wife Helen in 1938 and the couple had three children. He was a ham radio enthusiast.[2][3] He died in Rochester, Minnesota in 1999.[2]

References

  1. ^ a b c "Biographical Sketch of Charles Frederick Koelsch (1907-1999)". Charles Frederick Koelsch papers. University of Minnesota Libraries. Retrieved 29 December 2020.
  2. ^ a b c d e "In Memoriam". Badger Chemist: The Newsletter of the University of Wisconsin-Madison Chemistry Department. 44: 27. 2000. Retrieved 29 December 2020.
  3. ^ a b c d e f g h i Noland, Wayland E. (November 1975). "The Life and Times of Professor Emeritus C. Frederick Koelsch". The Minnesota Chemist. 27 (7): 7–8, 15–17. Retrieved 29 December 2020.
  4. ^ Koelsch, C. F. (August 1957). "Syntheses with Triarylvinylmagnesium Bromides. α,γ-Bisdiphenylene-β-phenylallyl, a Stable Free Radical". Journal of the American Chemical Society. 79 (16): 4439–4441. doi:10.1021/ja01573a053.
  5. ^ Zard, Samir Z. (2003). Radical reactions in organic synthesis. Oxford: Oxford University Press. p. 3. ISBN 9780198502401.
  6. ^ Matsui, Yasunori; Shigemori, Minoru; Endo, Toshiyuki; Ogaki, Takuya; Ohta, Eisuke; Mizuno, Kazuhiko; Naito, Hiroyoshi; Ikeda, Hiroshi (August 2018). "Spectroscopic and electrical characterization of α,γ-bisdiphenylene-β-phenylallyl radical as an organic semiconductor". Research on Chemical Intermediates. 44 (8): 4765–4774. doi:10.1007/s11164-018-3282-7. S2CID 102644089.