An Isolable One-Coordinate Lead(I) Radical with Strong g-Factor Anisotropy

Area of Science:

• Inorganic Chemistry
• Organometallic Chemistry
• Radical Chemistry

Background:

• Lead(I) species are typically highly reactive and difficult to isolate in condensed phases.
• Elusive lead-based radicals present significant challenges in chemical synthesis and characterization.

Purpose of the Study:

• To synthesize and characterize the first isolable free plumbylyne radical (Pb(I)).
• To investigate the electronic structure and reactivity of novel Pb(I) radicals.

Main Methods:

• Synthesis of a one-coordinate Pb(I) radical (plumbylyne radical 2).
• Reaction of plumbylyne radical 2 with an N-heterocyclic carbene (NHC) to form a two-coordinate Pb(I) radical 3.
• Characterization using theoretical calculations and electron paramagnetic resonance (EPR) spectroscopy.

Main Results:

• Successfully isolated and characterized the first free plumbylyne radical (2) and an NHC-ligated Pb(I) radical (3).
• Electron paramagnetic resonance and theoretical studies confirmed the unpaired electron resides primarily in the Pb 6p orbital.
• Radical 2 displayed significant g-factor anisotropy due to its unique one-coordinate lead atom.

Conclusions:

• The study presents the first isolable Pb(I)-based radicals, expanding the scope of stable main group radicals.
• The unique electronic and structural properties of these plumbylyne radicals offer new avenues for fundamental chemical research.
• Preliminary reactivity studies confirmed the Pb-centered radical nature and led to the isolation of plumbylenes.