NSF-ANR CHE: Encapsulated Bimetallic Complexes Based on Earth-abundant Metals for (Photo)Catalysis

With the support of the Chemical Catalysis program in the Division of Chemistry, Professor Neal Mankad of the University of Illinois Chicago is studying Earth-abundant metal complexes that can efficiently harvest energy from light to catalyze chemical transformations of importance to industrial chemical synthesis. To achieve this objective, the research team will create bimetallic reaction centers that are encapsulated by naturally occurring sugar molecules with cage-shaped structures called cyclodextrins.

The encapsulated reaction centers will be tested for their ability to promote light-driven chemical reactions. The surrounding cage structures are expected to increase efficiency by preventing unwanted side reactions and increasing catalyst stability. Not only is industrial chemical synthesis highly energy-intensive, but it also is dependent in many cases on precious metal resources.

Therefore, the use of Earth-abundant catalysts that harvest energy from light is a welcome advance that could positively impact energy efficient and environmental impact of society. This project is an international effort involving Drs. Sylvain Roland and Matthieu Sollogoub, both from Sorbonne University in France, who are funded by the French National Research Agency (ANR) and who possesses expertise in the synthesis of cyclodextrins and their derivatives, including those necessary for this collaborative project.

With the support of the Chemical Catalysis program in the Division of Chemistry, Professor Neal Mankad of the University of Illinois Chicago is studying bimetallic complexes that (i) include exclusively Earth-abundant metals and (ii) have the highest possible photoactivity in the visible light region. Emphasis will be placed on different designs of copper(I) complexes supported by modified cyclodextrins (CDs) as supramolecular scaffolds in which the copper centers are encapsulated.

In many cases, copper(I) will be connected to a second Earth-abundant metal through different strategies. In-depth studies of the encapsulated bimetallic complexes will provide fundamental knowledge about the factors affecting reactivity and light-harvesting ability, including details of both cooperativity between metal centers and supramolecular synergy between the binuclear reaction centers the CD cavities.

A major goal is to increase the efficiency of the photocatalytic systems at long wavelengths. In the long term, the project aims at developing sustainable photocatalytic systems leveraging properties of both the paired Earth-abundant metals and the CD cavity. While this project is fundamental in nature, its implications might be very applied and could enable emergence of sustainable industrial processes using environmentally benign metals.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.