Frustrated Lewis pair-ligated tetrelenes.

Area of Science:

• Organometallic Chemistry
• Main Group Chemistry
• Frustrated Lewis Pair Chemistry

Background:

• Phosphine-borane (PB) compounds are versatile ligands in coordination chemistry.
• Understanding the reactivity of PB chelates with heavier group elements is crucial for developing new synthetic methodologies.

Purpose of the Study:

• To investigate the reactivity of [PB{SiX2}] and [PB{GeX2}] adducts.
• To synthesize and characterize new methylene adducts of PB chelates.
• To explore the coordination chemistry of novel phosphine-borane frustrated Lewis pair (FLP) chelates.

Main Methods:

• Synthesis and characterization of [PB{SiX2}] and [PB{GeX2}] adducts.
• Reduction attempts and computational studies.
• Isolation and reactivity studies of the [PB{CH2}] adduct.
• Exploration of coordination chemistry with new PB FLP chelates.

Main Results:

• Reduction of [PB{SiX2}] and [PB{GeX2}] adducts exclusively yielded the free PB ligand.
• Computational analysis revealed a significant energy penalty for EX2 dissociation.
• The methylene adduct [PB{CH2}] was successfully isolated and its reactivity compared to heavier congeners.
• New PB FLP chelates were synthesized, and their preliminary coordination chemistry was investigated.

Conclusions:

• The studied PB chelates are stable towards reduction, preferentially releasing the PB ligand.
• The energy cost of EX2 dissociation influences the stability and reactivity of these adducts.
• Novel methylene adducts and PB FLP chelates expand the scope of phosphine-borane chemistry.