Nucleophilic Gallyl Anions Enable Ga─Au Bimetallic Ammonia Activation

Abstract

ABSTRACT Controlling the reactivity of low‐valent main‐group nucleophiles in small‐molecule activation remains a significant challenge. Here, we report the synthesis of a family of charge‐delocalized β‐diketiminate gallyl anions, accessible across the Li–Cs series, whose aggregation and ion pairing can be tuned to furnish a cation‐gated gallium(I) nucleophilic platform. Only the cesium crown‐encapsulated derivative forms a truly separated ion pair (SIP) that exhibits clean nucleophilic reactivity toward (IPr)AuCl to generate an unsupported Ga─Au bimetallic complex, isolable, and structurally authenticated. Coordination at Au enhances the Lewis acidity at gallium(I), enabling cooperative N─H and O─H σ‐bond activation under mild conditions via a substrate‐assisted proton‐shuttle pathway. This reactivity, exemplified by NH 3 and H 2 O, and extended to MeNH 2 and MeOH, is inaccessible to the free gallyl anions. These findings define a new gallium‐based nucleophilic platform for exploiting bimetallic cooperation in small‐molecule bond activation.