A dianionic C₃-symmetric scorpionate: synthesis and coordination chemistry

Area of Science:

• Coordination Chemistry
• Organometallic Chemistry
• Ligand Design

Background:

• Introducing charges into ligands modifies electronic properties and metal complex solubility.
• Homoscorpionate ligands offer unique coordination environments.

Purpose of the Study:

• To synthesize and characterize a novel dianionic, C3-symmetric ligand, tris-skatylmethylphosphonium (TSMP).
• To explore the coordination chemistry and metal exchange capabilities of the TSMP ligand.

Main Methods:

• Synthesis of the dipotassium salt of the TSMP ligand.
• Coordination studies with Cu(I), Fe(II), and Ni(II) complexes.
• X-ray crystallography to determine complex structures and coordination modes.

Main Results:

• The TSMP ligand, isolated as TSMPK2, is the first dianionic homoscorpionate capable of metal exchange.
• Demonstrated bridging μ2:κ2:κ1 and κ3 coordination modes with Cu(I) complexes.
• Synthesized octahedral high-spin κ3 complexes with Fe(II) and Ni(II) and a pseudotetrahedral 2:1 complex with Fe(II).

Conclusions:

• The TSMP ligand exhibits rich and tunable coordination chemistry due to its dianionic nature and metal exchange capability.
• Coordination modes are influenced by metal choice, ancillary ligands, and electrostatic interactions.