A Ni–Al Hydride Cluster Bearing Site-Differentiated Al Centers: Demonstration of Olefin Insertion and Alkyl Transfer

Heterometallic assemblies have been key in uncovering new modes of reactivity, with synergistic effects resulting from main-group metals such as Al drawing particular attention given the diverse ligand modalities accessible to aluminum. Utilizing a reducing Al-dihydride metalloligand LAlH2 and bis (1,5-cyclooctadiene)nickel(0), we report cluster 1, [LNiAl]3H5R (R = 4-cyclooctenyl). The cluster core features Al/Al–H moieties asymmetrically capping a Ni3 plane and coordinating to a Ni–Ni edge. The Al centers display electronically differentiating sites through Al–H addition, olefin insertion, and alkyl transfer. Crystallographic, DFT, and spectroscopic tools establish the presence of three distinct Al centers that adopt sigma-donating alane, sigma-accepting alane, and nonalane character.