A Lead(II) Substituted Triplet Carbene.

Area of Science:

• Organometallic Chemistry
• Photochemistry
• Carbene Chemistry

Background:

• Pincer-type ligands are crucial for stabilizing reactive metal complexes.
• Diazo compounds are versatile precursors for generating reactive intermediates.
• Lead complexes are less explored compared to other transition metals.

Purpose of the Study:

• To synthesize and characterize a novel lead-diazo compound.
• To investigate the photolytic behavior of the lead-diazo complex.
• To identify the resulting photoproduct and its reactivity.

Main Methods:

• Synthesis of a pincer-type lead complex.
• Reaction with a lithium diazo reagent.
• Photochemical irradiation (UV/Vis spectroscopy).
• Variable temperature NMR spectroscopy.
• Quantum-chemical calculations.

Main Results:

• Formation of a stable lead-diazo compound [L₃Pb(C(═N₂)TMS)][BArF₂₄].
• Photolysis yields a formal plumba-alkyne, identified as a metal-substituted triplet carbene.
• The carbene intermediate undergoes intermolecular C-H bond insertion with toluene.

Conclusions:

• The study demonstrates the successful synthesis and characterization of a lead-diazo complex.
• Photochemical activation provides access to a unique metal-substituted triplet carbene.
• This carbene exhibits reactivity, including C-H bond activation, opening new avenues in organolead chemistry.