A Redox-Confused Bismuth(I/III) Triamide with a T-Shaped Planar Ground State

Area of Science:

• Organometallic Chemistry
• Inorganic Chemistry
• Materials Science

Background:

• Bismuth compounds are known for diverse electronic structures and geometries.
• Pnictogen triamides typically adopt pyramidal geometries due to bonding characteristics.
• Understanding bismuth electronic configurations is crucial for developing new materials and catalysts.

Purpose of the Study:

• To synthesize and characterize a novel bismuth triamide complex.
• To elucidate the electronic structure and geometric preferences of the bismuth center.
• To investigate the reactivity and coordination behavior of the bismuth triamide.

Main Methods:

• Reaction of a tethered triamine ligand with tris(dimethylamino)bismuth (Bi(NMe2)3).
• X-ray crystallography to determine the molecular structure and bismuth coordination geometry.
• Spectroscopic methods (e.g., NMR, UV-Vis) to probe electronic structure.
• Coordination studies with Lewis bases (pyridine N-oxide, W(CO)5) to assess reactivity.

Main Results:

• A bismuth triamide with a T-shaped geometry at the bismuth center was successfully synthesized.
• The electronic structure was best described as containing significant Bi^I character.
• This represents the first structural model for edge inversion in bismuthines and a planar geometry for pnictogen triamides.
• The compound exhibited reactivity characteristic of Bi^III electrophiles, coordinating with both pyridine N-oxide and W(CO)5.
• Coordination with pyridine N-oxide indicated a potential coordination-induced oxidation state change at bismuth.

Conclusions:

• The synthesized bismuth triamide displays an unprecedented planar, T-shaped geometry and a Bi^I electronic configuration.
• This structure challenges conventional understanding of pnictogen triamide geometries, influenced by differing Bi-N and P-N bond polarities.
• The compound's reactivity, despite its Bi^I character, aligns with Bi^III electrophiles, suggesting complex electronic behavior and potential for redox activity.