Halogen Photoelimination from Sb^V Dihalide Corroles

Area of Science:

• Inorganic Chemistry
• Organometallic Chemistry
• Photochemistry

Background:

• Main-group p-block metals are suitable for two-electron reactions due to stable M(n) and M(n+2) redox states.
• Pnictogens, like antimony, exhibit a propensity for III/V redox cycling, crucial for catalytic processes.

Purpose of the Study:

• To synthesize and characterize antimony (Sb) corrole complexes in both Sb(III) and Sb(V) oxidation states.
• To investigate the photochemical behavior of Sb(V) corroles and their potential for M-X bond activation.

Main Methods:

• Synthesis and structural elucidation of Sb(III) and Sb(V) corrole complexes.
• Electrochemical studies to probe redox interconversion between Sb species.
• Time-dependent Density Functional Theory (TD-DFT) calculations to understand electronic transitions.
• Steady-state photolysis experiments to investigate photochemical reactivity.

Main Results:

• Successfully synthesized Sb(III) corrole and its Sb(V)X2 (X=Cl, Br) congeners.
• Electrochemical data indicated facile interconversion between Sb(III) and Sb(V)X2 states.
• TD-DFT calculations revealed antibonding character in excited states, correlating with Sb-X bond activation.
• Photolysis of Sb(V)X2 corroles efficiently converted them to Sb(III) corroles, confirming photoactivation of the Sb-X bond.

Conclusions:

• Antimony corroles provide a platform for exploring p-block metal photochemistry.
• The Sb(III)/Sb(V) redox couple can drive two-electron photochemistry, specifically M-X bond activation.
• This work lays the foundation for developing HX-splitting cycles utilizing pnictogen photochemistry.