Reversible Dissociation of a Dialumene

Dialumenes are neutral Al(I) compounds with Al=Al multiple bonds. We report the isolation of an amidophosphine-supported dialumene. Our X-ray crystallographic, spectroscopic, and DFT computational analyses reveal a long and extreme trans-bent Al=Al bond with low dissociation energy and bond-order. In solution, the dialumene can dissociate into monomeric Al(I) species. Reactivity studies reveal two modes of reaction: as dialumene or as aluminyl monomers.