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

The synthesis of two ambiphilic Ga/P-containing frustrated Lewis pairs (FLPs) [iPr₂P(C₆H₄)GaMes₂] (PGaMes2, 1, Mes = 2,4,6-Me₃C₆H₂) and [{iPr₂P(C₆H₄)}₂GaMes] (P2GaMes, 2) is reported. Motivated by the possibly higher degrees of Lewis acidity at the Ga centers in 1 and 2 compared to known-boron based chelates, these new Ga/P FLPs were reacted with soft main group elements, such as Te, as well as exploration of their ability to coordinate the parent aminoborane H₂B-NH₂ (generated via the dehydrogenation of H₃B·NH₃). In contrast to the known/stable chelate [iPr₂P(C₆H₄)BCy₂{H₂BNH₂}] (Cy = cyclohexyl), the corresponding Ga/P adduct [P2GaMes{H2BNH2}] (8) is unstable and releases B-N units such as borazine [HBNH]₃ over time, which is partially attributed to a hard-soft acid-base mismatch between N and Ga.