Reversible Dissociation of a Dialumene**

Abstract

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 computational DFT analyses reveal a long and extreme trans-bent Al=Al bond with a 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.