Bioinspired Copper(II) Complexes With N,S-Donor Ligands: Structure-Activity Relationships and Mechanistic Insights...

Area of Science:

• Coordination Chemistry
• Materials Science
• Electrochemistry

Background:

• Developing low-cost, energy-efficient materials is key for energy sustainability.
• Bioinspired coordination compounds offer a pathway to novel catalytic systems.
• Electrocatalytic hydrogen production is a critical area for renewable energy.

Purpose of the Study:

• To design and synthesize novel bioinspired copper complexes.
• To evaluate their electrocatalytic performance for hydrogen production in water.
• To elucidate the mechanistic pathways governing their catalytic activity.

Main Methods:

• Synthesis and structural characterization of isostructural copper complexes (Cu-L_N2S2 and Cu-L_N3S) using single-crystal X-ray crystallography.
• Electrocatalytic evaluation for hydrogen evolution reaction (HER) in acidic aqueous media.
• Mechanistic investigations using spectroscopic, analytical techniques, and density functional theory (DFT) calculations.

Main Results:

• Both copper complexes adopt a distorted square pyramidal geometry.
• Cu-L_N2S2 exhibited significantly higher electrocatalytic performance than Cu-L_N3S, with a turnover frequency (TOF) of 2.90 × 10³ s^-1 and 96% Faradaic efficiency.
• DFT calculations and mechanistic studies revealed distinct HER pathways (ECEC for Cu-L_N3S and CECE for Cu-L_N2S2).
• The mixed hard-soft donor environment and structural distortion in Cu-L_N2S2 are crucial for efficient hydrogen production.

Conclusions:

• Cu-L_N2S2 is a highly efficient electrocatalyst for sustainable hydrogen production in water.
• Ligand design and coordination geometry play a critical role in modulating catalytic activity.
• These findings contribute to the development of advanced materials for energy sustainability.