Organometallic Catalysis

One focus within our investigation of low-coordinate transition metal complexes is to explore their fundamental organometallic chemistry. We have studied the first-row metals iron, cobalt, and nickel with the goal of learning how to transform organic molecules with inexpensive metals rather than the precious metals that are most common in catalysis.

We have done this by studying a strange type of organometallic compounds: ones with unpaired electrons (“high-spin”), in which the metal shares 14 or fewer valence electrons rather than the usual 18. Our research shows that these unusually low-electron-count organometallic complexes are very useful for synthesis and catalysis.

We also study hydride complexes, which are at the heart of organometallic chemistry because they are involved in many catalytic reactions. We have isolated the first examples of three-coordinate transition metal complexes with hydride ligands. These very reactive compounds can break multiple bonds in alkenes, alkynes, and diazenes.

One important organometallic transformation involving metal hydride complexes is beta-hydride elimination. Through both experimental and computational investigations, we have learned that spin-state changes may be important when first-row metal compounds  undergo beta-hydride elimination.

We have more recently applied this fundamental knowledge to catalytic reactions. Two recent discoveries are that cobalt alkyl complexes can perform regioselective and stereoselective isomerization, and that cobalt(I) complexes catalyze hydrosilylation of alkenes.

In addition, we have synthesized a “masked two-coordinate” cobalt(I) complex that is highly reactive toward small molecules, including fluorocarbons (shown below) and carbon dioxide.

Relevant Publications

Julian C. Lo, Dongyoung Kim, Chung-Mao Pan, Jacob T. Edwards, Yuki Yabe, Jinghan Gui, Tian Qin, Sara Gutiérrez, Jessica Giacoboni, Myles W. Smith, Patrick L. Holland, Phil S. Baran
Fe-Catalyzed C-C Bond Construction from Olefins via Radicals
J. Am. Chem. Soc.  2017139, 2484-2503.  
K. Cory MacLeod, Richard A. Lewis, Daniel E. DeRosha, Brandon Q. Mercado, Patrick L. Holland
C-H and C-N Activation at Redox-Active Pyridine Complexes of Iron
Angew. Chem. Int. Ed.  201756, 1069-1072.  
Chi Chen, Maxwell Hecht, Aydin Kavara, William W. Brennessel, Brandon Q. Mercado, Daniel J. Weix, Patrick L. Holland
Rapid, Regioconvergent, Solvent-Free Alkene Hydrosilylation with a Cobalt Catalyst
J. Am. Chem. Soc.  2015137, 13244-13247.  
Patrick L. Holland
Distinctive Reaction Pathways at Base Metals in High-Spin Organometallic Catalysts
Acc. Chem. Res.  201548, 1696-1702.  
John A. Gladysz, et al.
Organometallics Roundtable 2013-2014
Organometallics  201433, 1505-1527.  
Thomas R. Dugan, Eckhard Bill, K. Cory MacLeod, William W. Brennessel, Patrick L. Holland
Synthesis, Spectroscopy and Hydrogen/Deuterium Exchange in High-Spin Iron(II) Hydride Complexes
Inorg. Chem.  201453, 2370-2380.  
Chi Chen, Thomas R. Dugan, William W. Brennessel, Daniel J. Weix, Patrick L. Holland
Z-Selective Alkene Isomerization by High-Spin Cobalt(II) Complexes
J. Am. Chem. Soc.  2014136, 945-955.  Coverage in Org. Chem. Highlights
Sarina M. Bellows, Thomas R. Cundari, Patrick L. Holland
Spin Crossover during β-Hydride Elimination in High-Spin Iron(II)- and Cobalt(II)-Alkyl Complexes
Organometallics   201332, 4741-4751.  Included in Virtual Issue Honoring Robert Bergman’s 2017 Wolf Prize in Chemistry
Brian L. Edelbach, Blaze M. Pharoah, Sarina M. Bellows, Peter R. Thayer, Charles N. Fennie, Ryan E. Cowley, Patrick L. Holland
An Expedient Synthesis of 2,4,6-Tris(trifluoromethyl)aniline
Synthesis  201244, 3595-3597.  
Thomas R. Dugan, Jonathan M. Goldberg, William W. Brennessel, Patrick L. Holland
Low-Coordinate Cobalt Fluoride Complexes: Synthesis, Reactions, and Production from C-F Activation Reactions
Organometallics  201231, 1349-1360.  
Barbara A. Reisner, Joanne L. Stewart, B. Scott Williams, Laurel A. Goj, Patrick L. Holland, Hilary J. Eppley, and Adam R. Johnson
Virtual Inorganic Pedagogical Electronic Resource Learning Objects in Organometallic Chemistry
J. Chem. Educ.   201289, 185-187.  
Benjamin R. Dible, Ryan E. Cowley, Patrick L. Holland
Remote Substitution on N-Heterocyclic Carbenes Heightens the Catalytic Reactivity of Their Palladium Complexes
Organometallics   201130, 5123-5132.  
Keying Ding, Ferdous Zannat, James C. Morris, William W. Brennessel, and Patrick L. Holland
Coordination of N-Methylpyrrolidone to Iron(II)
J. Organomet. Chem.   2009694, 4204-4208.  
Meghan M. Clark, William W. Brennessel, Patrick L. Holland
Bis(η5-pentamethylcyclopentadienyl)cobalt(II)
Acta Cryst. C   200965, m391.  More on Decamethylcobaltocene
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.   2008130, 6624-6638.  
Azwana R. Sadique, William W. Brennessel, and Patrick L. Holland
Reduction of COto CO Using Low-Coordinate Iron: Formation of a Four-Coordinate Iron Dicarbonyl Complex and a Bridging Carbonate Complex
Inorg. Chem.   200847, 784-786.  
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  200726, 3217-3226.  
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.   2005127, 7857-7870.  
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.  
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   200221, 4808-4814.