Poly-Hydride [Au^I ₇ (PPh₃ )₇ H₅ ](SbF₆ )₂ cluster complex: Structure, Transformation, and Electrocatalytic CO₂...

Area of Science:

• Inorganic Chemistry
• Nanomaterials Science
• Catalysis

Background:

• Hydride gold(I) bonds are typically labile, hindering the study of their structure-activity relationships in nanoclusters.
• Understanding gold nanocluster behavior is crucial for developing new catalytic applications.

Purpose of the Study:

• To synthesize and characterize a novel gold cluster containing multiple hydride ligands.
• To investigate the structural and electronic properties of gold nanoclusters with varying hydride content.
• To compare the electrocatalytic performance of gold nanoclusters in CO2 reduction.

Main Methods:

• Synthesis and characterization of [Au7(PPh3)7H5](SbF6)2 (Au7H5^2+).
• Photochemical transformation study from Au7H5^2+ to [Au8(PPh3)7]^2+ (Au8^2+).
• Verification of oxidation states using DFT, NMR, UV/Vis, and XPS.
• Electrocatalytic CO2 reduction reaction (CO2 RR) performance evaluation.
• Density Functional Theory (DFT) calculations to elucidate reaction mechanisms.

Main Results:

• Successfully synthesized and characterized Au7H5^2+, a gold cluster with five hydride ligands.
• Au7H5^2+ transformed into Au8^2+ upon exposure to light (300-450 nm).
• Au7H5^2+ demonstrated 98.2% selectivity for H2 production in CO2 RR.
• Au8^2+ showed 73.5% selectivity for CO production in CO2 RR.
• DFT calculations indicated hydride ligands inhibit CO2 RR compared to electron-donating hydrogen.

Conclusions:

• The study presents a stable gold cluster with multiple hydride ligands and its light-induced transformation.
• The presence of hydride ligands significantly influences the catalytic activity and selectivity in CO2 reduction.
• Gold nanoclusters with different structures and ligand compositions offer tunable pathways for CO2 conversion.