Ga/P-Based Ambiphilic Chelates and Their Reactivities with Main Group Elements

Area of Science:

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

Background:

• Frustrated Lewis pairs (FLPs) are reactive species formed by the combination of Lewis acids and bases that cannot form a classical adduct.
• Gallium (Ga) and Phosphorus (P) containing FLPs are of interest due to the tunable Lewis acidity of Ga centers.
• Previous studies have focused on boron-based FLPs for similar applications.

Purpose of the Study:

• To synthesize and characterize novel ambiphilic Ga/P-containing frustrated Lewis pairs (FLPs).
• To investigate the reactivity of these new Ga/P FLPs with soft main group elements and aminoborane.
• To compare the stability and reactivity of Ga/P FLPs with established boron-based FLPs.

Main Methods:

• Synthesis of two Ga/P FLPs: [iPr2P(C6H4)GaMes2] (PGaMes2, 1) and [{iPr2P(C6H4)}2GaMes] (P2GaMes, 2).
• Reaction of Ga/P FLPs with tellurium (Te).
• Exploration of the coordination of aminoborane (H2B-NH2) to the Ga/P FLPs.

Main Results:

• The Ga/P FLPs were successfully synthesized.
• The Ga/P FLPs reacted with tellurium.
• The Ga/P adduct with aminoborane, [P2GaMes{H2BNH2}] (8), was found to be unstable.
• Unstable adduct 8 decomposed over time, releasing borazine ([HBNH]3).

Conclusions:

• The synthesized Ga/P FLPs exhibit unique reactivity profiles.
• The instability of the Ga/P-aminoborane adduct is attributed to a hard-soft acid-base mismatch between nitrogen and gallium.
• Ga/P FLPs present different stability and reactivity compared to their boron-based counterparts.