Metal-Organic REagents for Light-Enabled Shuttling of protons and electrons

Introduction

Protons and electrons are the currency of energy conversion and play a key role in some of the most transformative technologies such as the reduction of N2, CO, or CO2. Exploiting water and sunlight as renewable resources for these transformations offers a means for solar-to-chemicals conversion. Thus, our ability to control the transfer of protons and electrons, preventing the more favorable formation of H2, poses an exciting fundamental problem.

Challenges in PCET

Strategies based on proton coupled electron transfer (PCET) have demonstrated key benefits by providing low energy pathways that bypass the most energetic, charged intermediates. However, important problems remain regarding the development of PCET shuttles that:

1. Behave as catalysts harnessing water and light.
2. Promote multi PCET to avoid unstable radical intermediates that undermine selectivity and efficiency.
3. Can be integrated into complex multielectron/multiproton transformations relevant to solar energy conversion, such as N2 reduction.

Proposed Solutions

I will address these problems by designing metal-organic PCET shuttles that target three specific objectives:

1. To merge light and electricity for reductive PCET in a novel photoelectrocatalytic strategy using molecular shuttles that exploit counter oxidation reactions of practical relevance.
2. To achieve unprecedented control over multi PCET to impact the selectivity of reductive transformations via the colocalization of redox and acid/base sites within coordination cages.
3. To integrate photo(electro)catalytic PCET in small molecule catalysis with new tandem approaches towards the reduction of N2 using light and water.

Conclusion

Overall, these objectives will provide unconventional tools to affect the mechanisms of reductive reactions. Besides transgressing the frontiers of knowledge in the field of PCET, and more generally energy conversion, More4Less has the potential to change the paradigm in which we develop catalytic systems for solar-to-chemical transformation.