Nathaniel Szymczak

Our research program uses fundamental principles of molecular design to address some of the grand challenges in the fields of small molecule activation and catalysis. We are interested in developing strategies to reversibly store energy in the form of chemical bonds, and also to rapidly convert abundant chemical (bio)feedstocks into value-added chemicals and fuels.

The overarching themes of our research program are to (a) understand how to exploit carefully positioned secondary-sphere sites to control reactivity, and (b) develop transition metal compounds to promote otherwise difficult transformations of small molecule chemical feedstocks such as N₂, CO₂, O₂, and CO.

We are working to establish new ways by which molecular catalysts can be tuned by the incorporation of pendent functional groups within a metal’s secondary coordination sphere environment. We are using these appended functional groups (hydrogen bond donor/acceptors, or Lewis acid/bases) to augment reactivity of the central transition metal in order to promote the activation/delivery of small molecules to appropriate substrates. Overall, our approach aims to move the emphasis away from the transition metal, and instead, place high importance on secondary-coordination sphere interactions (not directly bound to the metal) to develop new metal complexes and catalysts that synergistically engage substrates for binding/reduction, regulate activity, and ultimately incorporate earth-abundant metals.

Bioinorganic Modeling: Decoding the role secondary sphere interactions play to sustain life

We are developing small molecule systems to directly investigate the molecular level details of how noncovalent interactions facilitate highly challenging enzymatic reactions. Key questions include how acidic groups can facilitate charge transfer and activation of the components of the air we breathe (N₂, O₂).

Fluoroalkylation: Repurposing fluoroalkanes using Lewis pairs

We are targeting an acid/base pair approach to enable widely available fluoralkanes to be used as direct chemical precursors to medicinally important organic compounds. In contrast to alkyl anions, fluoroalkyl anions are inherently unstable, and require the development of new synthetic strategies.

Hydrogen Transfer Catalysis: Upgrading low cost chemical feedstocks to value added fuels and platform chemicals

We are developing homogeneous catalysts that efficiently removes H₂ from alcohols and amines and enable broader diversification from simple widely available feedstock chemicals. In some cases, the dehydrogenated compounds can be functionalized in a cascade reaction sequence to rapidly increase molecular complexity.

Second-Sphere Modifications for Catalyst Redesign: Uncovering cooperative activation and functionalization reactions

Our group takes inspiration from nature, where metalloenzymes use a network of positioned secondary sphere groups to achieve exquisite control over a given bond-breaking or forming reaction. To emulate these design principles, we are preparing new synthetic catalysts that use positioned acidic groups to direct substrate binding/activation to control a reaction’s chemo– and/or regioselectivity.

Representative Publications

Shanahan, J. P.; Szymczak, N. K.* Hydrogen Bonding to a Dinitrogen Complex at Room Temperature: Impacts on N₂ Activation. J. Am. Chem. Soc. 2019, 141, 8550-8556

Hale, L. V. A.;^ǂ Sikes, N. M.;^ǂ Szymczak, N. K.* Reductive C−C Coupling from α,β‐Unsaturated Nitriles by Intercepting Keteniminates. Angew. Chem. Int. Ed. 2019, 58, 1-6. *Selected as VIP article

Kiernicki, J. J; Shanahan, J. P. Zeller, M.; Szymczak, N. K.* Tuning Ligand Field Strength with Pendent Lewis Acids: Access to High Spin Iron Hydrides. Chem. Sci. 2019, 10, 5539-5545
*Selected as Editor’s Choice Article.

Geri, J. B.; Wade Wolfe, M. M.;Szymczak, N. K.* The Difluoromethyl Group as a Masked Nucleophile: A Lewis Acid/Base Approach.  J. Am. Chem. Soc., 2018, 140, 9404-9408. *Featured in JACS Young Investigator Virtual Issue, 2019.

Kiernicki, J. J; Zeller, M.; Szymczak, N. K.* Hydrazine Capture and N-N Bond Cleavage at Iron Enabled by Flexible Appended Lewis Acids.  J. Am. Chem. Soc.,  2017, 139, 18194-18197.

Geri, J. B.; Wade Wolfe, M. M.; Szymczak, N. K.* Borazine-CF₃^- Adducts for Rapid, Room Temperature, and Broad Scope Trifluoromethylation Angew. Chem., Int. Ed.,  2018, 57, 1-7 *Featured in Chemical & Engineering News, 2018, Jan. 1.

Geri, J. B.; Szymczak, N. K.* Recyclable Trifluoromethylation Reagents from Fluoroform.  J. Am. Chem. Soc.,  2017, 139, 9811-9814. *Featured in JACS Spotlights August 1, 2017.

Tseng, K-N T.; Rizzi, A. M.; Szymczak, N. K.*; Oxidant-Free Conversion of Primary Amines to Nitriles, J. Am. Chem. Soc., 2013, 135, 16352–16355

Tseng, K-N T.; Kampf, J. W.; Szymczak, N. K.*; Base-Free, Acceptorless, and Chemoselective Alcohol Dehydrogenation Catalyzed by an Amide-Derived NNN-Ruthenium(II) Hydride Complex. Organometallics, 2013, 32, 2046-2049

Tutusaus, O.; Ni, C.; Szymczak, N. K.*; A Transition Metal Lewis Acid-Base Triad System for Cooperative Substrate Binding. J. Am. Chem. Soc., 2013, 135, 3403-3406. *Featured in Chemical & Engineering News, 2013, 91, 29.

Research Areas(s)

• Energy Science
• Inorganic Chemistry
• Organic Chemistry
• Organometallic Chemistry
• Energy Storage

Award(s)

• JACS Young Investigator - ACS Virtual Issue, 2019
• Kavli Frontiers of Science Fellow – China, 2018
• Class of 1923 Memorial Teaching Award, 2017
• Camille Dreyfus Teacher-Scholar Award, 2016
• Sloan Research Fellowship, 2014
• NSF CAREER Award, 2014
• Emerging Investigator - ACS Virtual Issue in Bioinorganic Chemistry, 2015
• KAIST Distinguished Lectureship Award, 2014
• Dow Corning Assistant Professor of Chemistry 2012
• Young Investigator Award, ACS Inorganic Chemistry, 2006
• NSF IGERT Fellowship, 2004