Hydroxyl Transfer to Carbon Radicals by Mn(OH) vs Fe(OH) Corrole Complexes

Daniel C. Cummins, Jessica G. Alvarado, Jan Paulo T. Zaragoza, Muhammad Qadri Effendy Mubarak, Yen-Ting Lin, Sam P. de Visser, David P. Goldberg

Research output: Contribution to journalArticlepeer-review


The transfer of •OH from metal-hydroxo species to carbon radicals (R•) to give hydroxylated products (ROH) is a fundamental process in metal-mediated heme and nonheme C–H bond oxidations. This step, often referred to as the hydroxyl “rebound” step, is typically very fast, making direct study of this process challenging if not impossible. In this report, we describe the reactions of the synthetic models M(OH)(ttppc) (M = Fe (1), Mn (3); ttppc = 5,10,15-tris(2,4,6-triphenyl)phenyl corrolato3–) with a series of triphenylmethyl carbon radical (R•) derivatives ((4-X-C6H4)3C•; X = OMe, tBu, Ph, Cl, CN) to give the one-electron reduced MIII(ttppc) complexes and ROH products. Rate constants for 3 for the different radicals ranged from 11.4(1) to 58.4(2) M–1 s–1, as compared to those for 1, which fall between 0.74(2) and 357(4) M–1 s–1. Linear correlations for Hammett and Marcus plots for both Mn and Fe were observed, and the small magnitudes of the slopes for both correlations imply a concerted •OH transfer reaction for both metals. Eyring analyses of reactions for 1 and 3 with (4-X-C6H4)3C• (X = tBu, CN) also give good linear correlations, and a comparison of the resulting activation parameters highlight the importance of entropy in these •OH transfer reactions. Density functional theory calculations of the reaction profiles show a concerted process with one transition state for all radicals investigated and help to explain the electronic features of the OH rebound process.
Original languageEnglish
Pages (from-to)16053–16064
Number of pages12
JournalInorganic Chemistry
Issue number21
Early online date13 Oct 2020
Publication statusPublished - 2 Nov 2020


  • charge transfer
  • reaction products
  • transfer reactions
  • transition metals
  • transition states

Research Beacons, Institutes and Platforms

  • Manchester Institute of Biotechnology


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