Redox-Rich Metallocene Tetrazene Complexes: Synthesis, Structure, Electrochemistry, and Catalysis

Area of Science:

• Organometallic Chemistry
• Catalysis
• Cycloaddition Reactions

Background:

• Metallocenyl-substituted tetrazene complexes are novel compounds.
• Cobaltocene and ferrocene are key organometallic moieties.

Purpose of the Study:

• Synthesize and characterize novel metallocenyl-substituted tetrazene cyclopentadienyl cobalt complexes.
• Investigate the catalytic activity of these complexes in proton reduction.

Main Methods:

• Thermal and photochemical metal-centered cycloaddition reactions.
• Spectroscopic, structural, and electrochemical analyses.
• Electrochemical proton reduction assays.

Main Results:

• First synthesis of trimetallic CpCo-tetrazenido complexes with cobaltocene or ferrocene.
• Characterization revealed highly conjugated, colored, redox-active metallo-aromatic compounds.
• CpCo-tetrazenido complex with cobaltocene units catalyzed electrochemical proton reduction at 0.35 V overpotential.

Conclusions:

• The synthesized trimetallic CpCo compounds exhibit unique electronic and redox properties.
• Cobaltocene moieties are crucial for the observed proton reduction catalysis.
• Ferrocene-containing analogs were inactive, highlighting the importance of metal choice.