Dr. Adam Fiedler

Dr. Adam Fiedler
Dr. Adam FiedlerMarquette University

Wehr Chemistry Building, 433

MilwaukeeWI53201United States of America
(414) 288-7191
Curriculum Vitae

Chair and Professor

Bioinorganic Chemistry and Spectroscopy


Ph.D., University of Wisconsin-Madison

B.S., University of Wisconsin-Madison

Research Interests

My group's research falls within the general field of bio-inspired inorganic chemistry.  The common theme is the synthesis and characterization of inorganic complexes that mimic the structure and/or function of metalloenzymes.  All of our projects are multifaceted, combining inorganic coordination chemistry with mechanistic studies, spectroscopic characterization (UV-vis, EPR, MCD, X-ray absorption, resonance Raman), and computational (DFT) analysis.

Research Areas

  • Bio-inspired inorganic chemistry
  • Synthesis and spectroscopy of inorganic complexes
  • Coordination chemistry

Professional Experience

Professor Fiedler received his Ph.D. degree in inorganic chemistry under the direction of Thomas Brunold at the University at Wisconsin-Madison in 2006. After graduating from Madison, he began an NIH postdoctoral fellowship in the laboratory of Prof. Larry Que, Jr. at the University of Minnesota, where synthesized and characterized high-valent iron complexes with relevance to oxygen activation in biological systems. He joined the faculty at Marquette University in August 2009. Professor Fiedler's research interests are in the area of synthetic bioinorganic chemistry, spectroscopy, and computational methods.  Dr. Fiedler has received external research funding from the NSF and NIH, and currently serves as chairperson of the Chemistry Department.

Selected Publications

Please see the full list on Google Scholar.

  1. Ekanayake, D.M.; Sheridan, P.E.; Lindeman, S.V.; Fiedler, A.T.* “Diverse Coordination Geometries Derived from Trisaminocyclohexane Ligands with Appended Outer-Sphere Hydrogen Bond Donors.”  European Journal of Inorganic Chemistry 2023, 26, e202300434. doi.org/10.1002/ejic.202300434.

  2. Devkota, L.;  SantaLucia, D.J; Wheaton, A.M.;  Pienkos, A.J.; Lindeman, S.V.; Krzystek, J.; Ozerov, M.; Berry, J.F.; Telser, J.;* Fiedler, A.T.* “Spectroscopic and Magnetic Studies of Co(II) Scorpionate Complexes:  Is there a Halide Effect on Magnetic Anisotropy?”  Inorganic Chemistry 2023, 62, 5984-6002. doi.org/10.1021/acs.inorgchem.2c04468.

  3. Kumar, P.; Devkota, L.; Casey, M.C.; Fischer, A.A.; Lindeman, S.V.; Fiedler, A.T.* “Reversible Dioxygen Binding to Co(II) Complexes with Noninnocent Ligands." Inorganic Chemistry 2022, 61, 16664-16677. org/10.1021/acs.inorgchem.2c02246

  4. Pathiranage, W.LK.; Gumataotao, N.; Fiedler, A.T.;* Holz, R.C.;* Bennett, B.*  “Identification of an Intermediate Species along the Nitrile Hydratase Reaction Pathway by EPR Spectroscopy.” 

    Biochemistry 2021, 60, 3771-3782.  doi.org/10.1021/acs.biochem.1c00574 

  5. Ekanayake, D.M.; Pham, D.; Probst, A.L.; Miller, J.R.; Popescu, V.;* Fiedler, A.T.* “Electronic structures and spectroscopic signatures of diiron intermediates generated by O2 activation of nonheme iron(II)–thiolate complexes.” Dalton Transactions 2021, 50, 14432-14443.  doi.org/10.1039/D1DT02286E

  6. Ekanayake, D.M.; Fischer, A.A.; Elwood, M.E.; Guzek, A.M.; Lindeman, S.V.; Popescu, V.;* Fiedler, A.T.* “Nonheme Iron-Thiolate Complexes as Structural Models of Sulfoxide Synthase Active Sites.” Dalton Transactions 2020, 49, 17745-17757.  doi.org/10.1039/d0dt03403g

  7. Kumar, P.; SantaLucia, D.J.; Kaniewska-Laskowska, K.; Lindeman, S. V.; Ozarowski, A.; Krzystek, J.; Ozerov, M.; Telser, J.; Berry, J.F.;* Fiedler, A.T.* “Probing the Magnetic Anisotropy of Co(II) Complexes Featuring Redox-​Active Ligands.” Inorganic Chemistry 2020, 59, 16178-16193. doi.org/10.1021/acs.inorgchem.0c01812

  8. Fischer, A.A.; Miller, J.R.; Jodts, R.J.; Ekanayake, D.M.; Lindeman, S.V.; Brunold, T.C.;* Fiedler, A.T.* “Spectroscopic and Computational Comparisons of Thiolate-Ligated Ferric Nonheme Complexes to Cysteine Dioxygenase: Second-Sphere Effects On Substrate (Analogue) Positioning.” Inorganic Chemistry 2019, 58, 16487-16499. doi.org/10.1021/acs.inorgchem.9b02432

  9. Kumar, P.; Lindeman, S.V.; Fiedler, A.T.* “Cobalt Superoxo and Alkylperoxo Complexes Derived from Reaction of Ring-Cleaving Dioxygenase Models with O2.” Journal of the American Chemical Society 2019, 141, 10984-10987. doi.org/10.1021/jacs.9b05320

  10. Fischer, A.A.; Lindeman, S.V.; Fiedler, A.T.* “A Synthetic Model of the Nonheme Iron–Superoxo Intermediate of Cysteine Dioxygenase.”  Chemical Communications 2018, 54, 11344-11347.  doi.org/10.1039/C8CC06247A

  11. Wang, D.; Ekanayake, D.M; Lindeman, S.V.; Verani, C.N.;* Fiedler, A.T.* “Multielectron Redox Chemistry of Transition Metal Complexes Supported by a Non-innocent N3P2 Ligand: Synthesis, Characterization, and Catalytic Properties.” European Journal of Inorganic Chemistry 2018, 4133-4141. doi.org/10.1002/ejic.201800843 

  12. Fischer, A.A.; Lindeman, S.V., Fiedler, A.T.* “Spectroscopic and Computational Studies of Reversible O2 Binding by a Cobalt Complex Relevant to Cysteine Dioxygenase.” Dalton Transactions 2017, 46, 13229-13241. (Invited contribution to “Frontiers in Spectroscopic Techniques in Inorganic Spectroscopy” themed issue). doi.org/10.1039/C7DT01600J

  13. Kpogo, K.K.; Mazumder, S.; Wang, D.; Schlegel, H.B.;* Fiedler, A.T.;* Verani, C.N.* “Bimetallic Cooperativity in Proton Reduction with an Amido-Bridged Cobalt Catalysts.” Chemistry – A European Journal 2017, 23, 9272-9279. doi.org/10.1002/chem.201701982

  14. Stein, N.; Gumataotao, N.; Hajnas, N.; Wu, R.; Lankathilaka, K.P.W.; Bornscheuer, U.T.; Liu, D.; Fiedler, A.T.*; Holz, R.C.*; Bennett, B.* “Multiple States of Nitrile Hydratase from Rhodococcus equi TG328-2: Structural and Mechanistic Insights from EPR and DFT Studies.” Biochemistry 2017, 56, 3068-3077. doi.org/10.1021/acs.biochem.6b00876

  15. Fiedler, A.T.*; Fischer, A.A. “Oxygen Activation by Mononuclear Mn, Co, and Ni Centers in Biology and Synthetic Complexes.” Journal of Biological Inorganic Chemistry 2017, 22, 407-425. (Invited review article to the special issue: “60 Years of Oxygen Activation.”). doi.org/10.1007/s00775-016-1402-7

  16. Fischer, A. A.; Stracey, N.; Lindeman, S.V.; Brunold, T.C.*; Fiedler, A.T.* “Synthesis, X-​ray Structures, Electronic Properties, and O2​/NO Reactivities of Thiol Dioxygenase Active-​site Models.” Inorganic Chemistry 2016, 55, 11839-11853. doi.org/10.1021/acs.inorgchem.6b01931

  17. Baum, A.E.; Lindeman, S.V.; Fiedler, A.T.* “Mononuclear Iron-(hydro/semi)quinonate Complexes Featuring Neutral and Charged Scorpionates: Synthetic Models of Intermediates in the Hydroquinone Dioxygenase Mechanism.” European Journal of Inorganic Chemistry, 2016, 2455-2464. (Invited contribution to the special issue: “The Significance of Scorpionate Ligands 50 Years On.”). doi.org/10.1002/ejic.201501380

  18. Lane, A.C.; Barnes, C.L.; Antholine, W.E.*; Wang, D.; Fiedler, A.T.*; Walensky, J.R.* “Di- and Trinuclear Mixed-Valence Copper Amidinate Complexes from Reduction of Iodine.” Inorganic Chemistry 2015, 54, 8509-8517. doi.org/10.1021/acs.inorgchem.5b01161

  19. Wang, D.; Lindeman, S.V.; Fiedler, A.T.* “Bimetallic Complexes Supported by a Redox-Active Ligand with Two Pincer-Type Coordination Sites.” Inorganic Chemistry 2015, 54, 8744-8754. doi.org/10.1021/acs.inorgchem.5b01380

  20. Baum, A.E.; Park, H.; Lindeman, S.V.; Fiedler, A.T.* “Synthesis and Spectroscopic Characterization of High-Spin Mononuclear Fe(II) p-Semiquinonate Complexes.” Inorganic Chemistry 2014, 53, 12240-12242. doi.org/10.1021/ic502564r

  21. Wang, D.; Lindeman, S.V.; Fiedler, A.T.* “Synthesis of Homo- and Heterobimetallic NiII-MII (M = Fe, Co, Ni, Zn) Complexes Based on an Unsymmetric Ligand Framework: Structures, Spectroscopic Features, and Redox Properties.” Inorganica Chimica Acta 2014, 421, 559-567. doi.org/10.1016/j.ica.2014.07.018

  22. Bittner, M.M.; Lindeman, S.V.; Popescu C.V.;* Fiedler, A.T.* “Dioxygen Reactivity of Biomimetic Fe(II) Complexes with Noninnocent Catecholate, o-Aminophenolate, and o-Phenylenediamine Ligands.” Inorganic Chemistry 2014, 53, 4047-4061. doi.org/10.1021/ic403126p

  23. Baum, A.E.; Lindeman, S.V.; Fiedler, A.T.* “Preparation of a Semiquinonate-Bridged Diiron(II) Complex and Elucidation of its Geometric and Electronic Structures.” Chemical Communications  2013, 49, 6531-6533. doi.org/10.1039/c3cc42980f

  24. Wang, D.; Lindeman, S.V., Fiedler, A.T.* “Intramolecular Hydrogen Bonding in Cu(II) Complexes with 2,6-Pyridinedicarboxamide Ligands: Synthesis, Structural Characterization, and Physical Properties.”  European Journal of Inorganic Chemistry 2013, 4473-4484. doi.org/10.1002/ejic.201300579

  25. Bittner, M.M.; Kraus, D.; Lindeman, S.V.; Popescu, C.V.;* Fiedler, A.T.* “Synthetic, Spectroscopic and DFT Studies of Iron Complexes with Iminobenzo(semi)quinone Ligands: Implications for o-Aminophenol Dioxygenases.” Chemistry – A European Journal 2013, 19, 9686-9698. doi.org/10.1002/chem.201300520

  26. Park, H.; Bittner, M.M.; Baus, J.S.; Lindeman, S.V.; Fiedler, A.T.* “Fe(II) Complexes That Mimic the Active Site Structure of Acetylacetone Dioxygenase: O2 and NO Reactivity.” Inorganic Chemistry 2012, 51, 10279-10289. doi.org/10.1021/ic3012712

  27. Baum, A.E.; Park, H.; Wang, D.; Lindeman, S.V.; Fiedler, A.T.* “Structural, Spectroscopic, and Electrochemical Properties of Nonheme Fe(II)-Hydroquinonate Complexes: Synthetic Models of Hydroquinone Dioxygenases.” Dalton Transactions 2012, 41, 12244-12253. doi.org/10.1039/c2dt31504a

  28. Bittner, M.M.; Lindeman, S.V.; Fiedler, A.T.* “A Synthetic Model of the Putative Fe(II)-Iminobenzosemiquinonate Intermediate in the Catalytic Cycle of o-Aminophenol Dioxygenases.” Journal of the American Chemical Society 2012, 134, 5460-5463.  (This paper was selected for the “Models of Metalloenzymes” virtual issue). doi.org/10.1021/ja212163t

  29. Bittner, M.M.; Baus, J.S.; Lindeman, S.V.; Fiedler, A.T.* “Synthesis and Structural Characterization of Iron(II) Complexes with Tris(imidazolyl)phosphane Ligands:  A Platform for Modeling the 3-Histidine Facial Triad of Nonheme Fe Dioxygenases.” European Journal of Inorganic Chemistry 2012, 1848-1856. doi.org/10.1002/ejic.201101282

  30. Park, H.; Baus, J.S.; Lindeman, S.V.; Fiedler, A.T.*Synthesis and Characterization of Fe(II) b-Diketonate Complexes with Relevance to Acetylacetone Dioxygenase:  Insights into the Electronic Properties of the 3-His Facial Triad.”  Inorganic Chemistry 2011, 50, 11978–11989. doi.org/10.1021/ic201115s

Honors and Awards

  • Way Klingler Young Scholar Award, 2012
  • NSF CAREER Award, 2011
  • NIH Ruth Kirschstein National Research Service Award, 2007-2009

Faculty & Staff


Department of Chemistry

Todd Wehr Chemistry, 101
1414 W Clybourn St.
Milwaukee, WI 53233
(414) 288-3515

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