Hydride-Bridged Heteronuclear Complexes for Hydrogen Evolution: Electrocatalytic and Theoretical Studies

Area of Science:

• Inorganic Chemistry
• Organometallic Chemistry
• Electrochemistry
• Catalysis

Background:

• Electrocatalytic hydrogen evolution is crucial for sustainable energy technologies.
• Heterobimetallic complexes offer tunable electronic properties for catalysis.
• Selenolate and tellurolate ligands can bridge metal centers, influencing reactivity.

Purpose of the Study:

• To synthesize and characterize novel selenolate-bridged heterobimetallic hydride complexes.
• To investigate the effect of different metal centers (Mn, Re, Ir, Co) on electrocatalytic hydrogen evolution.
• To elucidate the structure-activity relationships governing their catalytic performance.

Main Methods:

• Synthesis of trichalcogenate-bridged heterodinuclear complexes.
• Conversion to hydride-bridged heterobimetallic complexes using LiBH4·THF.
• Characterization via multinuclear NMR, IR spectroscopy, and single-crystal X-ray diffraction.
• Electrocatalytic activity evaluation using cyclic voltammetry, spectroelectrochemistry, and Faradaic yield measurements.
• Computational analysis using Density Functional Theory (DFT).

Main Results:

• Successful synthesis of several selenolate- and tellurolate-bridged heterobimetallic complexes.
• Complex 3 exhibited higher electrocatalytic activity for hydrogen evolution compared to complex 4.
• DFT studies indicated that electron density distribution and metalloradical character correlate with catalytic performance.

Conclusions:

• The synthesized heterobimetallic hydride complexes are active electrocatalysts for hydrogen evolution.
• Metal identity and ligand environment critically influence catalytic efficiency.
• Computational insights provide a basis for designing more efficient hydrogen evolution catalysts.