Tweaking the bridge in metallocene Zr(IV)/W(IV) bimetallic hydrides.

Area of Science:

• Organometallic Chemistry
• Coordination Chemistry
• Catalysis

Background:

• Zirconocene complexes are versatile catalysts.
• Bridging hydride ligands are crucial in bimetallic systems.
• Understanding metal-metal interactions is key to catalyst design.

Purpose of the Study:

• To synthesize and characterize a novel bimetallic zirconocene-tungsten complex.
• To investigate the structural and electronic properties of the bridging hydride.
• To explore the reactivity of the bimetallic complex with Lewis bases, unsaturated substrates, and hydrogen.

Main Methods:

• Synthesis of the bimetallic complex via sigma-bond metathesis.
• Structural characterization using X-ray crystallography and NMR spectroscopy.
• Computational studies to analyze bonding and electronic structure.
• Reactivity studies with various substrates.

Main Results:

• A fluxional bimetallic complex [Cp2Zr(μ-H)(μ-η1:η5-C5H4)WHCp]+ was formed.
• The Zr(μ-H)W moiety exhibited an atypical out-of-plane arrangement.
• Coordination geometry and hydride bonding were modulated by Lewis bases and unsaturated substrates.
• Reactivity with H2 indicated that sigma-bond metathesis is the preferred pathway, preventing bimetallic cooperativity.

Conclusions:

• The study presents a novel bimetallic complex with a unique bridging hydride.
• The electronic and structural properties of the hydride bridge are tunable.
• The bridging hydride interaction hinders bimetallic cooperativity, favoring sigma-bond metathesis.