A titanium redox-switch enables reversible C-C bond forming and splitting reactions

Area of Science:

• Organometallic Chemistry
• Coordination Chemistry
• Catalysis

Background:

• Earth-abundant transition metals offer sustainable routes for organic synthesis.
• Mediating C-C bond formation and cleavage with electrical stimuli is a key challenge.
• Titanium complexes are explored for their unique reactivity in bond transformations.

Purpose of the Study:

• To investigate the reaction of a Ti(II) complex with an azide source for N-atom transfer and C-C coupling.
• To characterize the resulting dinuclear titanium complex and its electronic properties.
• To explore the reactivity of the dinuclear complex under oxidative conditions and compare with vanadium systems.

Main Methods:

• Synthesis and characterization of titanium complexes.
• Magnetic susceptibility and computational studies (DFT) to understand electronic structure.
• Electrochemical studies (cyclic voltammetry) to probe redox behavior.
• Comparative reactivity studies with vanadium nitride complexes.

Main Results:

• Formation of a dinuclear Ti(III) complex bridged by a disubstituted oxalimidamide ligand via N-atom transfer and C-C coupling.
• Identification of two magnetically isolated d1 Ti(III) centers and a reversible two-electron oxidation.
• Chemical oxidation leads to C-C bond cleavage, forming a Ti(III) complex with bridging carbodiimide ligands exhibiting antiferromagnetic coupling.

Conclusions:

• Demonstrated a novel pathway for C-C bond formation and cleavage mediated by titanium.
• Elucidated the electronic structure and redox properties of the dinuclear titanium complexes.
• Provided insights into reaction mechanisms and intermediate structures through comparative studies.