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.