Overview

To develop innovative photochemistry that enables new routes for synthesizing chemical feedstocks

Research portfolio

Photochemistry, photophysics, contrathermodynamic transformations

Focus: We develop new photochemistry and feedstocks in BioLEC, to expand the scope of mechanistic tools and reactive substrates available to the photocatalysis community. Drawing on the rich physical chemistry capabilities in BioLEC, we design new reactivities and modes of excitation to push the boundaries of photoexcitation and accessible redox potentials. Using this new chemistry we valorize feedstocks that were previously inaccessible to photochemistry, providing a pathway toward recycling environmental waste such as polymers.

Example publications

Suong T. Nguyen, Lydia R. Fries, James H. Cox, Yuting Ma, Brett P. Fors, Robert R. Knowles, “Chemical Recycling of Thiol Epoxy Thermosets via Light-Driven C–C Bond Cleavage”, J. Am. Chem. Soc. 2023, 145, 11151, available online.

Jesse A. Wisch, Xiao Liu, Patrick J. Sarver, Cesar N. Prieto Kullmer, Agustin Millet, David W. C. MacMillan, Barry P. Rand, “Plasmon Mediated Near-Field Energy Transfer From Solid-State, Electrically Injected Excitons to Solution Phase Chromophores”, Adv. Funct. Mater. 2023, available online.

Overview

Emulate and exploit biological systems for new or improved syntheses

Research portfolio

Spectroscopy, biosynthesis, biocatalysis

Focus: We have demonstrated how nature’s catalysts – enzymes – can mediate a variety of non-natural transformations when boosted by photoexcitation. By designing microenvironments in photoenzymes, we introduce functionality that first mimics and then exceeds that of natural systems. We have also replicated the separation of light harvesting and reactivity in photosynthesis through the development of a biohybrid photocatalyst that increased product yields by an order of magnitude or more. We will expand this strategy to various light-harvesting moieties, earth-abundant photocatalysts, and photoenzymes so that the enhancement from light-harvesting can be applied flexibly to transformations.

Example publications

Paul T. Cesana, Claire G. Page, Dvir Harris, Megan A. Emmanuel, Todd K. Hyster, Gabriela S. Schlau-Cohen, “Photoenzymatic Catalysis in a New Light: Gluconobacter “Ene”-Reductase Conjugates Possessing High-Energy Reactivity with Tunable Low-Energy Excitation”, J. Am. Chem. Soc. 2022, 144, 17516, available online.

Jose Carceller, Bhumika Jayee, Claire Page, Daniel Oblinsky, Nithin Chintala, Gustavo Mondragón-Solórzano, Jingzhe Cao, Zayed Alassad, Zheyu Zhang, Nathaniel White, Gregory Scholes, Sijia Dong, Todd Hyster, “Engineering a Photoenzyme to Use Red Light “,  ChemRxiv. 2024; doi:10.26434/chemrxiv-2024-cjs5j

Overview

To inform design of photocatalysts by elucidating photocatalysis mechanisms

Research portfolio

Organic synthesis, inorganic catalysts, spectroscopy

Focus: BioLEC researchers are adept at developing and applying a variety of advanced spectroscopic and physical chemistry techniques including transient absorption spectroscopy, organometallic synthesis, EPR, pulse radiolysis, and ultra-fast IR to study the mechanisms in multiple metallaphotoredox reactions, including C–O, C–N, and C–C couplings. Our studies advance fundamental knowledge of the elementary organometallic steps available through visible light excitation. We are now building on these efforts with the goal of gaining a global understanding of how changes to substrate, ligand, and photocatalyst identity affect the reaction mechanism. We use this understanding to design improved and new dual transition metal/photoredox coupling reactions, and to expand the catalog of photocatalysts to include more abundant metal complexes.

Example publications

Amy Y. Chan, Atanu Ghosh, Jonathan T. Yarranton, Jack Twilton, Jian Jin, Daniela M. Arias-Rotondo, Holt A. Sakai, James K. McCusker, David W. C. MacMillan, “Exploiting the Marcus inverted region for first-row transition metal-based photoredox catalysis”, Science 2023, 382, 191, available online.

Stephen DiLuzio, Lakshmy Kannadi Valloli, Max Kudisch, Daniel T. Chambers, Garry Rumbles, Obadiah G. Reid, Matthew J. Bird, Hannah J. Sayre, “Reconceptualizing the Ir^III Role in Metallaphotoredox Catalysis: From Strong Photooxidant to Potent Energy Donor”, ACS Catal. 2024, available online.