On the Reaction of Pacman-Phosphanes with Lewis Acids

Area of Science:

• Organometallic Chemistry
• Coordination Chemistry
• Supramolecular Chemistry

Background:

• Pacman phosphanes are macrocyclic ligands with unique structural properties.
• Lewis acids are electron-pair acceptors crucial in various chemical reactions.
• Understanding ligand-Lewis acid interactions is key to designing new materials and catalysts.

Purpose of the Study:

• To investigate the reactivity of Pacman phosphanes with different Lewis acids.
• To characterize the resulting adducts and explore their structural and electronic properties.
• To elucidate the bonding modes and coordination behavior in these complexes.

Main Methods:

• Synthesis and isolation of Pacman phosphane-Lewis acid adducts.
• Full characterization using spectroscopic and crystallographic techniques.
• Density Functional Theory (DFT) and quantum chemical calculations for electronic structure analysis.

Main Results:

• Reactions with boranes (BPh3, B(C6F5)3) yielded mono- and di-adducts, with B(C6F5)3 favoring di-adduct formation.
• DFT calculations indicated that N-bonded adducts are more thermodynamically stable than P-bonded adducts.
• Reaction with GaCl3 produced an unexpected salt, [Pacman-GaCl2]+[GaCl4]-, containing a GaN2C2 heterocycle and a P atom in quadruple coordination (formal P(III)).

Conclusions:

• Pacman phosphanes exhibit diverse reactivity with Lewis acids, leading to unique coordination complexes.
• The electronic and steric properties of the Lewis acid significantly influence the reaction outcome.
• The formation of unusual coordination geometries and heterocyclic structures highlights the versatility of Pacman phosphanes in coordination chemistry.