A Phosphanyl-Phosphagallene that Functions as a Frustrated Lewis Pair

Area of Science:

• Organometallic Chemistry
• Main group chemistry
• Low-coordinate phosphorus chemistry

Background:

• Phosphagallenes are compounds containing a phosphorus-gallium double bond.
• Their synthesis and stability are of interest in main group chemistry.

Purpose of the Study:

• To synthesize novel phosphagallenes with varying phosphanyl moieties.
• To investigate the stability and reactivity of these new compounds.

Main Methods:

• Synthesis via reaction of (phosphanyl)phosphaketenes with gallium carbenoid Ga(Nacnac).
• Characterization of synthesized phosphagallenes and their reaction products.

Main Results:

• Phosphagallenes (1a/1b) featuring P=Ga bonds were successfully synthesized.
• Unsaturated phosphagallene 1a rearranged to a P=P containing spirocycle.
• Saturated phosphagallene 1b exhibited high thermal stability.
• 1b demonstrated frustrated Lewis pair behavior, activating H2 and forming a CO2 adduct.

Conclusions:

• The stability of phosphagallenes is dictated by the saturation of the phosphanyl group.
• Saturated phosphagallenes are robust and exhibit Lewis pair reactivity.