A diazene-bridged diruthenium complex with structural restraint defined by single meta-diphosphinobenzene

Area of Science:

• Organometallic Chemistry
• Coordination Chemistry
• Supramolecular Chemistry

Background:

• Mimicking enzymatic reactions requires confined coordination spaces with tunable flexibility.
• Dinuclear complexes offer unique structural and electronic properties for catalytic applications.

Purpose of the Study:

• To synthesize and characterize a novel dinuclear ruthenium complex with a flexible coordination environment.
• To investigate the reactivity of the dinuclear complex with hydrazine and explore the formation of diazene-bridged structures.

Main Methods:

• Synthesis of a dinuclear ruthenium complex featuring 1,3-bis(diphenylphosphino)benzene (DPPBz) as a non-chelating ligand.
• Reaction of the dinuclear complex with hydrazine to induce a 2-electron/2-proton transfer.
• Characterization of the resulting diazene-bridged complex using spectroscopic and crystallographic techniques.

Main Results:

• A dinuclear ruthenium complex with an open framework, stabilized by DPPBz without metal-metal bonding, was successfully synthesized.
• Treatment with hydrazine led to the formation of a diazene-bridged complex.
• The diazene-bridged complex exhibited intramolecular N-H···Cl hydrogen bonds.
• A monophosphine ligand failed to stabilize a similar dinuclear structure, highlighting the importance of the DPPBz ligand's conformation-enforcing ability.

Conclusions:

• The DPPBz ligand facilitates the construction of flexible dinuclear ruthenium frameworks suitable for redox reactions.
• The dinuclear complex readily undergoes a formal 2e-/2H+ transfer with hydrazine to form a stable diazene-bridged species.
• Controlled coordination environments are crucial for stabilizing reactive intermediates and products in organometallic chemistry.