Functional Al/Cd Heterometallics─From Controlled Al(I) Transfer to Nucleophilic Transfer of Cadmium Ions.

Low-valent cadmium compounds have remained largely unexplored as electron reservoirs, with no precedent for their use in reduction or bond activation chemistry. Here, we address this gap by integrating low-valent aluminum into the cadmium coordination sphere. Aluminylene insertion into Cd{N(TMS)} affords bi- and trimetallic cadmium aluminyls and , featuring covalent yet tunable Al-Cd bonding. While is irreversibly formed, exhibits dynamic reactivity, enabling reversible [AlCp*] transfer─a rare and previously undocumented feature in heterobimetallic aluminum chemistry. Acting as a thermodynamically stable yet chemically reactive surrogate for free Al(I), enables selective Al(I) shuttling to B, Cd, Zn, and Ag substrates (compounds , -). The cooperative Al-Cd framework in and further promotes bond activation of heterocumulenes such as carbodiimides and CO, with serving as a source of nucleophilic cadmium─an unprecedented reactivity mode for this element (compounds -). Detailed quantum chemical calculations elucidate the electronic structures of and as well as the mechanism for both Al(I) transfer and heterocumulene insertion. These findings establish a platform for bimetallic cooperativity in small-molecule activation and lay the groundwork for Al(I)-based multimetallic systems relevant to future catalysis and main group/transition-metal synergy.