above image credit: Ermler et al, FEBS Letts, 2009, 583, 585
The generation of dihydrogen (H2) as a chemical fuel is desirable as a sustainable and carbon-free fuel source. In fact, H2 can be generated from simple precursors: H2O and electrons. Currently, metallic platinum (Pt) is the best and most widely utilized catalyst for H2 generation. However, the low earth abundance and corollary high cost of Pt prohibits widespread, delocalized use of such a process.
Research in the Rose group is inspired by one of nature’s H2 utilizing enzymes: Mono-Iron Hydrogenase, often abbreviated HMD-H2ase. The enzyme is also known as “cluster-free” hydrogenase due to its lack of an [Fe4S4] redox cluster (unlike the di-iron and nickel-iron hydrogenases). Of all the transition metals, iron is the cheapest and most earth abundant. Therefore development of an inexpensive, reliable, Fe-based catalyst could alter the landscape of H2 production.
Our group uses the crystallographically characterized mono-Fe-H2ase active site as inspiration to prepare small molecule mimics of the enzyme.The enzyme active site presents a unique array of donors to the Fe center not yet found anywhere else in nature, including an N-bound pyridinone cofactor and an unusual Fe-C(acyl) bond.
The design of polydentate ligands (metal-binding units) that include sp2-carbonyl-type C-donors is a focus of the lab. We use the resulting Fe complexes as structural and spectroscopic models to understand the properties and function of the Fe-H2ase active site. The wide variety of donor types and ligand architectures available through chemical synthesis is one particular advantage compared to the standard amino acids in a protein-based biochemical approach.
Related techniques include organic ligand synthesis, inorganic synthesis, X-ray crystallography, and inorganic spectroscopy (EPR, Mossbauer, NMR, UV/vis, XPS).
T. A. Manes and M. J. Rose. Rigid scaffolds for the design of molecular catalysts and biomimetic active sites: A case study of anthracene-based ligands for modeling mono-iron hydrogenase (Hmd). Coord. Chem. Rev. 2017, 353, 295-308. Link
Z.-L. Xie, G. Durgaprasad and M. J. Rose.Substitution Reactions of Iron(II) Carbamoyl-Thioether Complexes Related to Mono-Iron Hydrogenase. Dalton Trans. 2017, 46, 10814. Link
J. P. Shupp, A. R. Rose and M. J. Rose. Synthesis and Interconversions of Reduced, Alkali-Metal Supported Iron-Sulfur-Carbonyl Complexes. Dalton Trans. 2017, 46, 9163-9171. Link
J. Seo, T. E. Sotman, E. R. Sullivan, B. D. Ellis, T. Phung and M. J. Rose. Structural and Electronic Modifications of Pyridones and Pyrones via Regioselective Bromination and Trifluoromethylation. Tetrahedron 2017, 73, 4519-4528. Link
21. S. Kuppuswamy, J. Wofford, C. Joseph, A. K. Ali, V. M. Lynch, P. A. Lindahl, and M. J. Rose. Structures, Interconversions and Spectroscopy of Carbonyl Clusters with an Interstitial Carbide: Localized Iron Center Reduction via Cluster Oxidation. Inorg. Chem. 2017, 56, 5998-6012. Link
J. Seo, T. A. Manes and M. J. Rose. Structural and Functional Synthetic Model of Mono-Iron Hydrogenase Featuring an Anthracene Scaffold. Nature Chem. 2017, 9, 552-557. Link
T. A. Manes and M. J. Rose. Mono- and Di-nuclear Manganese Carbonyls Supported by 1,8-Disubstituted (L = Py, Ar-SMe, Ar-SH) Anthracene Ligand Scaffolds. Inorg. Chem. 2016, 55, 5127-5138. Link
G. Durgaprasad, Z.-L. Xie and M. J. Rose. Iron Hydride Detection and Intramolecular Hydride Transfer in a Synthetic Model of Mono-Iron Hydrogenase with a CNS Chelate. Inorg. Chem. 2016, 55, 386-389. Link
K. A. Thomas Muthiah, G. Durgaprasad, Z.-L. Xie, O. M. Williams, C. Joseph, V. M. Lynch and M. J. Rose. Mononuclear Iron(II) Dicarbonyls Derived from NNS Ligands: Structural Models Related to a Possible “Pre-Acyl” Active Site of Mono-Iron (Hmd) Hydrogenase. Eur. J. Inorg. Chem. 2015. 1675-1691. Link
J. Seo, A. Ali, M. J. Rose. Novel Ligand Architectures for Metalloenzyme Modeling: Anthracene-based Ligands for Synthetic Modeling of Mono-[Fe] Hydrogenase. Comments Inorg. Chem. 2014, 34, 103-113. Link
S. E. A. Lumsden, G. Durgaprasad, K. A. Thomas Mutiah, M. J. Rose. Tuning Coordination Modes of Pyridine/Thioether Schiff Base (NNS) Ligands to Mononuclear Manganese Carbonyls. Dalton Trans. 2014, 43, 10725. Link