T. Brent Gunnoe
Organometallic chemistry, inorganic chemistry, homogeneous catalysis, small molecule activation
The development of more efficient synthetic methods represents a major economic and environmental challenge for the chemical industry. With research interests that span the fields of inorganic and organic chemistry, we focus on the preparation and characterization of new transition metal complexes that are capable of activating organic molecules toward novel reactivity. By concentrating on fundamental aspects of inorganic and organometallic chemistry, our efforts are ultimately directed toward the rational design of single-site catalysts that form the foundation of new homogeneous synthetic methodologies.
Petroleum distillates make up a considerable fraction of the synthetic building blocks available to the chemical industry. With the steep rise in demand for oil, the efficient use of fossil resources is becoming increasingly important. Carbon and hydrogen are the major elemental constituents of fossil-derived products. Thus, one area of focus for our group is the design of complexes that selectively break C-H bonds and transform them into useful products. For example, we are exploring the use of late transition metal systems for catalytic C-C bond formation reactions that proceed through metal-mediated C-H activation. Systems based on Ru(II), Pt(II), Rh(III) and Pt(IV) developed in our labs catalyze the addition of aromatic (including arenes and heteroaromatic substrates) C-H bonds across the C=C bonds of olefins. By understanding how the metal identity, metal oxidation state, and ancillary ligand identities impact this reaction step, we can design improved catalysts.
Another area of interest is the reactivity of transition metal complexes with high d-electron counts that possess amido, nitrene, oxo, hydroxide and alkoxide ligands, which we are seeking to apply toward hydrocarbon functionalization reactions. By accessing systems with highly electrophilic metal centers yet basic/nucleophilic non-dative ligands, we can take advantage of tandem activation of organic substrates. We are exploring the application of such systems toward the activation of both non-polar (e.g., dihydrogen and C-H) bonds as well as polar bonds. For example, we have recently developed Cu catalysts for the addition of O-H, N-H and S-H bonds across the multiple bonds of olefins and alkynes. Both intramolecular and intermolecular variants have been demonstrated. In addition, we are using C-H activation reactions by transition metal alkoxide systems as a foundation to develop catalysts for the partial oxidation of hydrocarbons.
In addition to projects focused on organometallic chemistry and homogeneous catalysis, the Gunnoe group collaborates with a molecular biology group to design chemical delivery systems for novel insecticides and pesticides. This project, which has been funded by the United States Department of Agriculture, seeks to exploit complementary expertise in the two research groups to design new biotechnologies.
Catalytic Synthesis of "Super" Linear Alkenyl Arenes Using an Easily Prepared Rh(I) Catalyst, Webster-Gardiner, M. S., Chen, J., Vaughan, B. A., McKeown, B. A., Schinski, W., Gunnoe, T. B.* J. Am. Chem. Soc. 2017, 139, 5474-5480. DOI: 10.1021/jacs.7b01165. This manuscript was highlighted in Chemical and Engineering News 2017, 95(17), 8.
Mechanistic Studies of Single-Step Styrene Production Using a Rhodium(I) Catalyst,Vaughan, B. A., Khani, S. K., Gary, J. B., Kammert, J. D., Webster-Gardiner, M. S., McKeown, B. A., Davis. R. J., Cundari, T. R.*, Gunnoe, T. B.* J. Am. Chem. Soc. 2017, 139, 1485-1498. DOI: 10.1021/jacs.6b10658
Aerobic Epoxidation of Olefin by Platinum Catalysts Supported on Mesoporous Silica Nanoparticles, Munz, D., Wang, D., Moyer, M. M., Webster-Gardiner, M. S., Kunal, P., Watts, D., Trewyn, B. G.*, Vedernikov, A. N.*, Gunnoe, T. B.* ACS Catalysis 2016, 6, 4584–4593. DOI: 10.1021/acscatal.6b01532
Organometallic Complexes Anchored to Conductive Carbon for Electrocatalytic Oxidation of Methane at Low Temperature, Joglekar, M., Nguyen, V., Pylypenko, S., Ngo, C., Li, Q., O’Reilly, M.E., Gray, T.S., Hubbard, W.A., Gunnoe, T. B.*, Herring, A. M.*, Trewyn, B.G.*. J. Am. Chem. Soc. 2016, 138, 116-125. This manuscript was highlighted in C&E News, featured on cover of J. Am. Chem. Soc., and selected for JACS Spotlights.
A Rhodium Catalyst for Single-Step Styrene Production, Vaughan, B. A., Webster-Gardiner, M. S., Cundari, T. R.*, Gunnoe, T. B.* Science 2015, 348, 421-424. DOI: 10.1126/science.aaa2260. This manuscript was highlighted in Chemical and Engineering News 2015, 93 (17), 26.