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 are 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.
Selective monooxidation of light alkanes using chloride and iodate. Fortman, G. C., Boaz, N. C., Munz, D., Konnick, M. M., Periana, R. A., Groves, J. T.*, Gunnoe, T. B.* J. Am. Chem. Soc. ASAP.
1,2-Addition of Dihydrogen across Rh(III)–OMe Bonds. Burgess, S. A., Devarajan, D., Bolaño, T.,Ess, D. H.*, Gunnoe, T. B.*, Sabat, M., Myers, W. H. Inorg. Chem. 2014, 19;53:5328-5340.
PtII Catalyzed Ethylene Hydrophenylation: Influence of Dipyridyl Chelate Ring Size on Catalyst Activity and Longevity. McKeown, B. A., Gonzalez, H. E., Gunnoe, T. B.*, Cundari, T. R.*, Sabat, M. ACS Catalysis 2013, 3, 1165–1171.
Facile and Regioselective C–H Bond Activation of Aromatic Substrates by an Fe(II) Complex Involving a Spin-Forbidden Pathway. Kalman, S. E., Petit, A., Gunnoe, T. B.*, Ess, D. H.*, Cundari, T. R.*, Sabat, M. Organometallics 2013, 32, 1797-1806.
Variable pathways for oxygen atom insertion into metal-carbon bonds: the case of Cp*W(O)2(CH2SiMe3). Mei J, Carsch KM, Freitag CR, Gunnoe TB, Cundari TR. J Am Chem Soc. 2013, 135:424-35.
Intramolecular Hydroalkoxylation and Hydroamination of Alkynes Catalyzed by Cu(I) Complexes Supported by N-Heterocyclic Carbene Ligands. Pouy, M. J., Delp, S. A., Uddin, J., Ramdeen, V. M., Cochrane, N. A., Gunnoe, T. B.*, Cundari, T. R.*, Sabat, M., Myers, W. H. ACS Catalysis 2012, 2, 2182-2193.
Mechanistic Studies of Ethylene Hydrophenylation Catalyzed by Bipyridyl Pt(II) Complexes. McKeown, B. A., Gonzalez, H. E., Friedfeld, M. R., Gunnoe, T. B.*, Cundari, T. R.*, Sabat, M. J. Am. Chem. Soc. 2011, 133, 19131-19152.
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