Reversible Dissociation of a Dialumene

• Published in: Angewandte Chemie International Edition Vol. 60; no. 46; pp. 24702 - 24708
• Main Authors: Falconer, Rosalyn L., Byrne, Keelan M., Nichol, Gary S., Krämer, Tobias, Cowley, Michael J.
• Format: Journal Article
• Language: English
• Published: WEINHEIM Wiley 08.11.2021; Wiley Subscription Services, Inc; John Wiley and Sons Inc
• Edition: International ed. in English
• Subjects: aluminium; aluminium(I) compounds; Chemical bonds; Chemistry; Chemistry, Multidisciplinary; Computer applications; Crystallography; dialumene; Energy of dissociation; Free energy; Heat of formation; low-valent atoms; Monomers; multiple bonds; Physical Sciences; Science & Technology; ALUMINUM; aluminium(I) compounds; ACTIVATION; BENZENE ADDUCT; dialumene; COMPOUND; BONDS; aluminium; REACTIVITY; low-valent atoms; multiple bonds; EQUIVALENT
• ISSN: 1433-7851; 1521-3773
• DOI: 10.1002/anie.202111385

Dialumenes are neutral AlI 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 AlI species. Reactivity studies reveal two modes of reaction: as dialumene or as aluminyl monomers. A highly trans‐bent dialumene has marginal Al=Al double‐bond character and, in solution, can dissociate into monomeric aluminyl fragments. Reactivity studies reveal that both the dialuminene and aluminyl monomer can be trapped by varying the reaction partner. DFT calculations elaborate the origins of the extreme trans‐bending, weak Al=Al bond, and define substituent effects in dialumenes.