Testing functional anchor groups for the efficient immobilization of molecular catalysts on silver surfaces

Area of Science:

• Surface science
• Catalysis
• Organometallic chemistry

Background:

• Controlling molecule-surface interactions is key for fabricating hybrid systems and surface-immobilized molecular catalysts.
• Rhenium bipyridine complexes are prominent catalysts for CO2 reduction.
• Sulfur anchor groups can modify complex-surface interactions.

Purpose of the Study:

• To investigate the surface anchoring and growth behavior of a sulfurated rhenium bipyridine complex on a silver surface.
• To compare the immobilization efficiency and adsorption configuration of the sulfurated complex with its parent compound.
• To understand the role of sulfur anchor groups in controlling molecule-surface interactions for potential catalytic applications.

Main Methods:

• Deposition of fac-Re(S-S-bpy)(CO)3Cl onto Ag(001) at room temperature.
• Analysis using scanning tunneling microscopy (STM) and density functional theory (DFT) calculations.
• Characterization of complex thermostability via infrared absorption and nuclear magnetic resonance spectroscopy.

Main Results:

• The sulfurated complex (fac-Re(S-S-bpy)(CO)3Cl) shows more efficient surface immobilization compared to the parent complex (fac-Re(bpy)(CO)3Cl).
• Sulfurated complex nucleates as single molecules and clusters, while the parent complex primarily nucleates in clusters at surface steps.
• STM and DFT analysis reveal that over 90% of the sulfurated complexes adsorb in a geometric configuration similar to the parent complex.

Conclusions:

• Sulfur modification enhances the surface immobilization efficiency of rhenium bipyridine complexes on Ag(001).
• The study provides direct comparison of growth behavior and adsorption configurations.
• Findings are crucial for designing surface-immobilized molecular catalysts with controlled interactions.