Diosmium carbonyl sawhorse complexes containing a ferrocenedicarboxylato ligand

Abstract

In an attempt to prepare a supramolecular assembly consisting of two, three, or four diosmium carbonyl sawhorse units linked together by dicarboxylato ligands, the reaction of [Os₃(CO)₁₂] with ferrocene-1,1′-dicarboxylic acid, Fe(C₅H₄COOH)₂, was carried out with microwave heating. Instead of an assembly, the lone diosmium product was the single sawhorse complex [Os₂(μ-ferrocene-1,1′-dicarboxylato)(CO)₆] (1) with a tetradentate doubly bridging Fe(C₅H₄CO₂^–)₂ ligand, a metal–metal single bond, four equatorial carbonyl ligands, and two axial carbonyl ligands. Two additional sawhorse complexes, [Os₂(μ-ferrocene-1,1′-dicarboxylato)(CO)₄(tri-p-tolylphosphine)₂] (2) and [Os₂(μ-ferrocene-1,1′-dicarboxylato)(CO)₄(N,N-dimethylaminomethylferrocene)₂] (3), were prepared by substituting the axial CO ligands in 1 with P- or N-donor ligands, respectively. Clusters 1, 2, and 3 represent the first examples of carbonyl sawhorse complexes with ferrocenedicarboxylato ligands, and all three were characterized with single-crystal X-ray diffraction studies.

Graphcial Abstract

Keywords:

• Sawhorse complexes
• osmium carbonyl clusters
• ferrocene ligands
• dicarboxylato ligands
• X-ray crystallography

Disclosure statement

The authors report there are no competing interests to declare.

Acknowledgement

We thank Dr. Lee Daniels for assistance with the treatment of the crystallographic disorder in 1.

Additional information

Funding

We are grateful to The Welch Foundation (Grant R-0021) for financial support.