PSb⁺P Ligand: Platform for a Stibenium to Transition-Metal Interaction

Area of Science:

• Inorganic Chemistry
• Organometallic Chemistry
• Coordination Chemistry

Background:

• Cationic divalent pnictogen ligands (nitrenium, phosphenium) are well-studied.
• Coordination chemistry of the heavier stibenium ion (Sb+) is less explored.
• Facilitating Sb+-metal interactions requires specialized ligand design.

Purpose of the Study:

• To design and synthesize a tridentate P-Sb+-P ligand for enhanced Sb+-metal interactions.
• To investigate the coordination chemistry of this stibenium ligand with late transition metals.
• To characterize the resulting metal-stibenium complexes and their bonding.

Main Methods:

• Synthesis of a P-Sb+-P ligand precursor complexed with silver triflate.
• Reaction of the silver complex with Rh(I) and Ir(I) precursors.
• Structural characterization using single-crystal X-ray crystallography.
• Computational studies to analyze bonding interactions.

Main Results:

• Successful synthesis of a P-Sb+-P ligand and its silver complex (2).
• Formation of novel stibenium-transition-metal complexes with Rh(I) and Ir(I) ([3][OTf] and [4][OTf]).
• Confirmation of a bridging M-Sb+-M structure via X-ray crystallography.
• Theoretical evidence for three-center delocalized M-Sb+-M bonding.

Conclusions:

• The P-Sb+-P ligand effectively coordinates to late transition metals.
• The study demonstrates the feasibility of stibenium ions in bridging metal centers.
• Computational analysis confirms unique delocalized bonding in these novel complexes.