Department of Chemistry
Alvin L. and Verla R. Kwiram Endowed Professor of Chemistry
Ph.D. California Institute of Technology, 1982
(Inorganic, Organometallic, Bioinorganic, and Physical Organic Chemistry)
(206) 543-2083
Email: mayer@chem.washington.edu
Mayer group website
Research in the Mayer group spans the fields of inorganic, organometallic, bioinorganic, and physical organic chemistry. Professor Mayer is also a member of the NSF-funded Center for Enabling New Technologies in Catalysis (CENTC) which draws together a group of investigators conducting research aimed toward the development of new catalytic systems.
Mayer and his students are studying how redox reactions are coupled to bond formation and bond cleavage. A primary focus is on the selective oxidation of organic compounds by transition metal complexes. Such oxidations are employed throughout chemical industry and are common in biological systems. The aims of the research are to understand the fundamental principles that underlie these processes, and to use that knowledge to design new reagents and catalysts for selective oxidation reactions.
One focus of research is the synthesis of new oxidizing compounds and the discovery of new oxidation reactions. In most transition metal complexes, the ligands are electron rich and act as nucleophiles. But in strongly oxidizing complexes, ligands can act as electrophiles. Addition to an electrophilic ligand often results in oxidation of the ligand, reduction of the metal, and formation of new chemical bond(s). For instance, OsO4 oxidizes H2 and alkane C–H bonds, apparently by attack of the σ-bond on the electrophilic oxo group. This work is being extended to the synthesis and reactivity of other oxidizing metal complexes.
Professor Mayer and his group are building a new fundamental understanding of reactions in which a proton and an electron are transferred together. One class of these reactions are hydrogen atom transfers, which are key steps in chemical processes from combustion and industrial selective hydrocarbon oxidations to the catalytic cycles of a variety of metalloenzymes. They have shown for the first time that the rates of hydrogen atom transfer processes follow Marcus theory, that they can be understood in terms of the driving force for transfer of H, and the intrinsic barriers to this transfer. The driving force is related to the strength of the bond the oxidant can make to a hydrogen atom. Since a hydrogen atom is an electron and a proton, this driving force can be determined from the affinity of a reagent for an electron (its redox potential) and a proton (its pKa). For instance, the iron complex shown below looks like an unlikely organic oxidant, but it abstracts H• from organic molecules because the oxidizing iron accepts the electron and the ligand accepts the proton.
In the example shown, the iron complex oxidizes a hydroxylamine by removal of a hydrogen atom. The cobalt analog of this iron complex has a similar redox potential and pKa, yet it reacts much slower. This is due to a much larger intrinsic barrier for the cobalt, due to its having to interconvert high-spin Co(II) with low-spin Co(III) . Based on these ideas, it is possible to predict reactivity, for metal complexes, enzyme active sites, and industrial catalysts. In a related organic project, oxidation of the phenol-amine proceeds via concerted transfer of an electron (to the oxidant) and a proton (from the phenol to the amine), as shown below.
All of these projects involve synthesis, spectroscopy of various kinds, and mechanistic and kinetic studies. This broad exposure to different approaches and techniques is very stimulating and helps to prepare students for a variety of future endeavors.
"Large Ground-State Entropy Changes for Hydrogen Atom Transfer Reactions of Iron Complexes” E. A. Mader, E. R. Davidson, and J. M. Mayer J. Am. Chem. Soc. 2007, 129, 5153-5166.
"Synthesis and Reactivity of a RuIII bis(anilide) Dimer by Oxidative Addition of an N,N’ – disubstituted Hydrazine” J. M. Hoover, A. G. DiPasquale, J. M. Mayer*, and F. E. Michael* Organometallics 2007, 26, 3297-3305.
"Methane Oxidation by Aqueous Osmium Tetroxide and Sodium Periodate; Inhibition of Methanol Oxidation by Methane” Osako, T.; Watson, E. J.; Dehestani, A; Bales, B. C.; Mayer, J. M. Angew. Chemie, Int. Ed., 2006, 45, 7433-7436.
"Concerted Proton-Electron Transfer in the Oxidation of Hydrogen-Bonded Phenols” Rhile, I.J.; Markle, T.F.; Nagao, H.; DiPasquale, A.G.; Lam, O.P.; Lockwood, M.A.; Rotter, K.; Mayer, J.M. J. Am. Chem. Soc. 2006, 128, 6075-6088.
"Ligand-Assisted Reduction of Osmium Tetroxide with Molecular Hydrogen via a [3+2] Mechanism” Dehestani, A.; Lam, W.H.; Hrovat, D.; Davidson, E.R.; Borden, W.T.; Mayer, J.M. J. Am. Chem. Soc. 2005, 127, 3423-3432.
Gerhard Closs Lecturer, University of Chicago, January 2007
First recipient of the Paul Hopkins Faculty Award, University of Washington Department of Chemistry, May, 2004
Reilly Lecturer at Notre Dame University, three lectures, Sept. 16-18, 2003
E.L. King Lecturer at the University of Colorado Boulder, five lectures, July 9-13, 2001
Distinguished Summer Lecturer in Inorganic Chemistry at Northwestern University, 2001 (three lectures) August 14-16, 2001
Associate Editor, Inorganic Chemistry, January 2001 - present