Home Home

Research Research Home Low-Coordinate Complexes Nitrogen Activation Organometallic Catalysis M-L Multiple Bonds Nanochemistry Publications

People Group Home Group Description Holland Bio Holland CV (PDF)

Pictures Pictures Home Holland Lab

Resources Links Publications Inorganic Challenges Group Guidelines Group Meeting Schedule

Department of Chemistry, University of Rochester

Organometallic Catalysis

We are interested in the fundamental organometallic chemistry of low-coordinate complexes. Because the metals in groups 7-10 of the periodic table are used for surface reactions like the Fischer-Tropsch process and the steam reforming of methane, we currently focus on these metals. We have synthesized the first three-coordinate methyl complexes of iron and cobalt, and the iron work has been extended to a large range of hydrocarbon ligands. The paramagnetic organometallic iron complexes have 12 valence electrons, in contrast to the 18-electron, diamagnetic compounds that dominate organometallic chemistry. We hope to show the capabilities of unusually low-electron-count organometallics for potential use in synthesis and catalysis.

As one example of the use of this chemistry, we have synthesized the first iron(II) fluoride complexes and shown that they are intermediates in the catalytic hydrodefluorination of fluorinated arenes and alkenes. In the hydrodefluorination reaction, a strong C-F bond in the starting material is broken and replaced with a C-H bond. Catalytic C-F bond breaking is rare, and potentially useful for digesting fluorinated materials that are environmentally persistent.

We also study hydride complexes, which are at the heart of organometallic chemistry because they are involved in innumerable catalytic processes. As the culmination of an effort to make hydride complexes that are highly reactive yet can be isolated, we have made the first examples of three-coordinate transition metal complexes with hydride ligands. These compounds can break strong bonds such as multiple bonds in alkenes, alkynes, and diazenes.

In our most recent work, we have isolated three-coordinate cobalt(II) and cobalt(I) complexes, and shown the properties of a "masked two-coordinate" cobalt(I) complex that is highly reactive toward small molecules. Current research focuses on the use of these compounds for the catalytic reactions of organic molecules.

Jeremy M. Smith, Rene J. Lachicotte, Patrick L. Holland, "Three-coordinate, 12-electron organometallic complexes of iron(II): synthesis and insertion of CO to give square pyramidal complexes," Organometallics 2002, 21, 4808-4814. (PDF)

Javier Vela, Jeremy M. Smith, Rene J. Lachicotte, Patrick L. Holland, "Alkyl group isomerisation in three-coordinate iron(II) complexes," Chem. Commun. 2002, 2886-2887. (PDF)

Javier Vela, Sridhar Vaddadi, Thomas R. Cundari, Jeremy M. Smith, Elizabeth A. Gregory, Rene J. Lachicotte, Christine J. Flaschenriem, Patrick L. Holland, "Reversible Beta-Hydrogen Elimination of Three-Coordinate Iron(II) Alkyl Complexes: Mechanistic and Thermodynamic Studies," Organometallics 2004, 23, 5226-5239. (DOI)

Elizabeth A. Gregory, Rene J. Lachicotte, Patrick L. Holland, "A Cationic Three-Coordinate Iron(II) Complex and the Reaction of Diketiminate with Ethyl Diazoacetate," Organometallics 2005, 24, 1803-1805. (DOI)

Javier Vela, Jeremy M. Smith, Ying Yu, Nicole A. Ketterer, Christine J. Flaschenriem, Rene J. Lachicotte, Patrick L. Holland, "Synthesis and Reactivity of Low-Coordinate Iron(II) Fluoride Complexes and Their Use in the Catalytic Hydrodefluorination of Fluorocarbons," J. Am. Chem. Soc. 2005, 127, 7857-7870. (DOI)

Nathan A. Eckert, Adriana Dinescu, Thomas R. Cundari, Patrick L. Holland, "A T-Shaped Three-Coordinate Nickel(I) Carbonyl Complex and the Geometric Preferences of Three-Coordinate d⁹ Complexes," Inorg. Chem. 2005, 44, 7702-7704. (DOI)

Ying Yu, William W. Brennessel, and Patrick L. Holland, "Borane B-C Bond Cleavage by a Low-Coordinate Iron Hydride Complex and N-N Bond Cleavage by the Hydridoborate Product," Organometallics 2007, 26, 3217-3226. (DOI)

Azwana R. Sadique, William W. Brennessel, and Patrick L. Holland, "Reduction of CO₂ to CO Using Low-Coordinate Iron: Formation of a Four-Coordinate Iron Dicarbonyl Complex and a Bridging Carbonate Complex," Inorg. Chem. 2008, 47, 784-786. (DOI)

Ying Yu, Azwana R. Sadique, Jeremy M. Smith, Thomas R. Dugan, Ryan E. Cowley, William W. Brennessel, Christine J. Flaschenriem, Eckhard Bill, Thomas R. Cundari, Patrick L. Holland, "The Reactivity Patterns of Low-Coordinate Iron Hydride Complexes," J. Am. Chem. Soc. 2008, 130, 6624-6638. (DOI)

Thomas R. Dugan, Patrick L. Holland, "New Routes to Low-Coordinate Iron Hydride Complexes: The Binuclear Oxidative Addition of H₂," J. Organomet. Chem. 2009, 694, 2825-2830. (Special Issue on Organometallics for Energy Conversion) (DOI)

Keying Ding, Ferdous Zannat, James C. Morris, William W. Brennessel, and Patrick L. Holland, "Coordination of N-Methylpyrrolidone to Iron(II)," J. Organomet. Chem. 2009, 694, 4204-4208. (DOI)

Keying Ding, Thomas R. Dugan, William W. Brennessel, Eckhard Bill, and Patrick L. Holland, "Synthesis, Properties, and Reactivity of Diketiminate-Supported Cobalt Fluoride Complexes," Organometallics 2009, 28, 6650-6656. (DOI)

Thomas R. Dugan, Xianru Sun, Elena V. Rybak-Akimova, Olayinka Olatunji-Ojo, Thomas R. Cundari, Patrick L. Holland, "A Masked Two-Coordinate Cobalt(I) Complex That Activates C-F Bonds," J. Am. Chem. Soc. 2011, 133, 12418-12421. (DOI)

Benjamin R. Dible, Ryan E. Cowley, Patrick L. Holland, "Remote Substitution on N-Heterocyclic Carbenes Heightens the Catalytic Reactivity of Their Palladium Complexes," Organometallics, in press.