Redox active iron nitrosyl units in proton reduction electrocatalysis

Area of Science:

• Inorganic chemistry
• Sustainable energy
• Catalysis

Background:

• Developing efficient molecular catalysts for dihydrogen production from protons and electrons is crucial for a sustainable energy future.
• The active site of [FeFe]-hydrogenase, featuring a 2Fe2S core, serves as a benchmark for synthetic catalyst design.

Purpose of the Study:

• To synthesize and characterize a novel diiron complex with nitrosyl ligands, mimicking the [FeFe]-hydrogenase active site.
• To investigate the redox properties and catalytic activity of the designed complex for proton reduction.

Main Methods:

• Synthesis of a binuclear [(NO)Fe(N2S2)Fe(NO)2](+) complex with bridging thiolates.
• Electrochemical studies to determine redox levels and stability.
• Density functional theory (DFT) calculations to understand electronic structure and bonding.

Main Results:

• The synthesized diiron complex exhibits structural integrity across two redox levels.
• Both the Fe(NO) and Fe(NO)2 units within the complex are redox-active.
• Experimental and theoretical data reveal significant orbital mixing, facilitating electron uptake, storage, and proton reduction.

Conclusions:

• The novel diiron complex with nitrosyl ligands effectively mimics key aspects of the [FeFe]-hydrogenase active site.
• The complex demonstrates potential as a molecular catalyst for sustainable dihydrogen production.
• Understanding the electronic interplay is key to designing future catalysts for energy conversion.