An end-on-coordinated As4 tetrahedron

Area of Science:

• Organometallic chemistry
• Inorganic chemistry
• Materials science

Background:

• The synthesis and reactivity of polyarsenic clusters are of significant interest in inorganic chemistry.
• Understanding the coordination behavior of As4 tetrahedra with transition metals is crucial for developing novel materials and catalysts.

Purpose of the Study:

• To investigate the reaction of a ruthenium complex with an As4 transfer reagent.
• To characterize the resulting coordination complex and its reactivity.
• To explore the differences in reactivity between arsenic and phosphorus clusters with ruthenium.

Main Methods:

• Reaction of [Cp*Ru(dppe)Cl] with [Ag(η(2)-As4)2](+)[pftb](-).
• Characterization of the product [Cp*Ru(dppe)(η(1)-As4)](+)[pftb](-) using spectroscopic techniques.
• Further reaction with a second cationic ruthenium complex fragment.
• Density Functional Theory (DFT) calculations to rationalize the observed reactivity.

Main Results:

• Successful synthesis of [Cp*Ru(dppe)(η(1)-As4)](+)[pftb](-) featuring an unprecedented end-on coordinated As4 tetrahedron.
• The reaction with a second ruthenium fragment resulted in cleavage of one basal As-As bond, not a second end-on coordination.
• Observed reactivity differs significantly from analogous reactions with phosphorus clusters.

Conclusions:

• Ruthenium complexes can coordinate to As4 tetrahedra in an end-on fashion.
• The reactivity of the As4 cluster with ruthenium differs from phosphorus, showing basal bond cleavage.
• DFT calculations provide insights into the electronic and structural factors governing this unique reactivity.