Gutmann–Beckett method

In chemistry, the Gutmann–Beckett method is an experimental procedure used by chemists to assess the Lewis acidity of molecular species. Triethylphosphine oxide (Et3PO, TEPO) is used as a probe molecule and systems are evaluated by 31P-NMR spectroscopy. In 1975, Viktor Gutmann used 31P-NMR spectroscopy to parameterize Lewis acidity of solvents by acceptor numbers (AN).[1] In 1996, Michael A. Beckett recognised its more generally utility and adapted the procedure so that it could be easily applied to molecular species, when dissolved in weakly Lewis acidic solvents.[2] The term Gutmann–Beckett method was first used in chemical literature in 2007.[3]

  1. ^ U. Mayer, V. Gutmann, and W. Gerger, "The acceptor number – a quantitative empirical parameter for the electrophilic properties of solvents", Monatshefte fur Chemie, 1975, 106, 1235–1257. doi: 10.1007/BF00913599
  2. ^ M.A. Beckett, G.C. Strickland, J.R. Holland, and K.S. Varma, "A convenient NMR method for the measurement of Lewis acidity at boron centres: correlation of reaction rates of Lewis acid initiated epoxide polymerizations with Lewis acidity", Polymer, 1996, 37, 4629–4631. doi: 10.1016/0032-3861(96)00323-0
  3. ^ G.C. Welch, L.Cabrera, P.A. Chase, E. Hollink, J.M. Masuda, P. Wei, and D.W. Stephan,"Tuning Lewis acidity using the reactivity of "frustrated Lewis pairs": facile formation of phosphine-boranes and cationic phosphonium-boranes", Dalton Trans., 2007, 3407–3414. doi: 10.1039/b704417h