My group uses and develops computational chemistry tools to discover reaction mechanisms, reactivity principles, and design catalysts that are experimentally realized.
1. Computational catalyst design with industrial application
Theory and computation are most powerful when making experimental predictions. The development of accurate quantum mechanical tools enables prediction of molecular catalysts, but there are limited cases of genuine prediction followed by experimental realization. My lab is expert at developing computational techniques to design new molecular organometallic catalysts for industrial energy and materials processes. Over the past several years we have partnered with Chevron-Phillips Chemical Co. to computationally design new selective ethylene oligomerization catalysts to target alpha olefins. Read about our recent success story: Kwon, D-H.; Fuller, J. T. III; Kilgore, U. J.; Sydora, O. L.; Bischof, S. M.; Ess, D. H.* “Computational Transition-State Design Provides Experimentally Verified Cr(P,N) Catalysts for Control of Ethylene Trimerization and Tetramerization” ACS Catal. 2018, 8, 1138-1142. (https://pubs.acs.org/doi/abs/10.1021/acscatal.7b04026).
We thank Chevron Phillips Chemical Co. for support of this work.
2. Computational studies of alkane C-H functionalization reactions
Large quantities of light alkanes from natural gas and readily available aromatic hydrocarbons provides motivation to develop homogeneous catalytic C-H bond functionalization reactions. A long-term goal of my group is to use computational chemistry tools to develop general principles on mechanisms, intermediates, reactivity, and selectivity for hydrocarbon C-H functionalization reactions by p-block main-group compounds as well as provide prediction of new catalysts. Read about our work on TlIII, PbIV, IIII, and HgII (Science 2014, 343, 1232; Angew. Chem. Int. Ed. 2014, 53, 10490; Organometallics 2015, 34, 5485; ACS Catal. 2016, 6, 4312; Organometallics, 2017, 36, 109).
We thank the U.S. Department of Energy, Office of Basic Energy Sciences, Catalysis Sciences for support of this work “Theory of Main-Group, p-Block Hydrocarbon Functionalization Reactions” DE-SC0018329.
3. Computational studies on multinuclear catalysis
Mononuclear complexes remain the target of the vast majority of catalyst designs. This is part because mechanisms and general principles of dinuclear metal-metal interactions and their impact on catalytic reaction steps remains underdeveloped. My group is playing a major role in the current revival in the use of dinuclear complexes to catalyze reactions with new mechanisms that are faster and more selective compared to traditional mononuclear catalysts. My group’s long-term goals are to discover new mechanisms, reactivity, and selectivity available for two metals compared to one metal and design new dinuclear catalysts and reactions. This has led to collaboration with more than eight experimental research groups around the world. Our recent published works include discoveries of new mechanisms and the origin of reactivity for Ni-Ni catalyzed alkyne cyclotrimerization, Ir-Ta catalyzed alkene hydrogenation, Pd-Ti catalyzed allylic amination, and Rh-Rh catalyzed aziridination and arene C-H amination (ACS Catal. 2017, 7, 4796; Science 2016, 353, 1144; ACS Catal. 2015, 5, 1840; J. Am. Chem. Soc. 2015, 137, 7371; Science 2014, 343, 61). The goals of our current work include development of reactivity and selectivity principles by comparing dinuclear versus mononuclear catalysts and determine the impact of metal-metal pairing. Additionally, we are using calculations to design new dinuclear catalysts for thermal arene borylation and asymmetric reactions.
This work is funded by the National Science Foundation, Chemical Catalysis, Theory and Design of Transition-Metal Heterodinuclear and Homodinuclear Catalytic Reactions CHE-1764194
4. Computational tools development
My group has developed two major programs that are currently distributed to computational chemistry groups around the world. The first is an efficient and easy to use Python program used to locate minimum energy crossing points (MECPro) for organometallic spin crossover reactions. This program can be freely downloaded from the Internet (http://www.chem.byu.edu/faculty/daniel-h-ess/mecp-software-download/). The second tool is a C++ quasiclassical direct dynamics program and graphical interface called DynSuite, which is freely available. My group also tests and develops practical and efficient methods for treating open-shell singlet species through the use of either spin projection techniques or fractional spin density functional theory (J. Phys. Chem. A 2011, 115, 76; J. Phys. Chem. A 2012, 116, 4922; J. Chem. Phys. 2012, 137, 114112).
5. Organometallic reaction dynamics
Metal-mediated organometallic reaction mechanisms are assumed to be appropriately described by minimum energy pathways mapped out by density functional calculations. Using our newly developed DynSuite program, we have discovered several examples where dynamical influences cause the “skipping” of high-energy organometallic intermediates and blurs the demarcation between classic mechanisms. Please check back soon for publications on this topic!