Henry Rzepa's Blog Chemistry with a twist

December 24, 2012

How to tame an oxidant: the mysteries of “tpap” (tetra-n-propylammonium perruthenate).

tpap[1], as it is affectionately known, is a ruthenium-based oxidant of primary alcohols to aldehydes discovered by Griffith and Ley. Whereas ruthenium tetroxide (RuO4) is a voracious oxidant[2], its radical anion countered by a tetra-propylammonium cation is considered a more moderate animal[3]. In this post, I want to try to use quantum mechanically derived energies as a pathfinder for exploring what might be going on (or a reality-check if you like). 



  1. S.V. Ley, J. Norman, W.P. Griffith, and S.P. Marsden, "Tetrapropylammonium Perruthenate, Pr4N+RuO4 -, TPAP: A Catalytic Oxidant for Organic Synthesis", Synthesis, vol. 1994, pp. 639-666, 1994. http://dx.doi.org/10.1055/s-1994-25538
  2. D.G. Lee, U.A. Spitzer, J. Cleland, and M.E. Olson, "The oxidation of cyclobutanol by ruthenium tetroxide and sodium ruthenate", Canadian Journal of Chemistry, vol. 54, pp. 2124-2126, 1976. http://dx.doi.org/10.1139/v76-304
  3. D.G. Lee, Z. Wang, and W.D. Chandler, "Autocatalysis during the reduction of tetra-n-propylammonium perruthenate by 2-propanol", The Journal of Organic Chemistry, vol. 57, pp. 3276-3277, 1992. http://dx.doi.org/10.1021/jo00038a009

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