Diberyllocene, a stable compound of Be(I) with a Be–Be bond

• Published in: Science (American Association for the Advancement of Science) Vol. 380; no. 6650; pp. 1147 - 1149
• Main Authors: Boronski, Josef T., Crumpton, Agamemnon E., Wales, Lewis L., Aldridge, Simon
• Format: Journal Article
• Language: English
• Published: United States The American Association for the Advancement of Science 16.06.2023
• Subjects: Aluminum; Beryllium; Crystallography; Iodides; Room temperature; X-ray crystallography
• ISSN: 0036-8075; 1095-9203; 1095-9203
• DOI: 10.1126/science.adh4419

The complex diberyllocene, CpBeBeCp (Cp, cyclopentadienyl anion), has been the subject of numerous chemical investigations over the past five decades yet has eluded experimental characterization. We report the preparation and isolation of the compound by the reduction of beryllocene (BeCp 2 ) with a dimeric magnesium(I) complex and determination of its structure in the solid state by means of x-ray crystallography. Diberyllocene acts as a reductant in reactions that form beryllium-aluminum and beryllium-zinc bonds. Quantum chemical calculations indicate parallels between the electronic structure of diberyllocene and the simple homodiatomic species diberyllium (Be 2 ). Most people who have heard of beryllium know of it as a structural component of emeralds. Its molecular chemistry is more obscure but has provoked decades of controversy over whether the element can be coaxed into bonding with itself. Boronski et al . now report a long-elusive example of a molecule stable in solid state at room temperature that features a beryllium–beryllium bond (see the Perspective by Dutton). Each beryllium center is also bonded to a cyclopentadienyl ligand. The compound was characterized by x-ray crystallography and reacted reductively with metal iodides to form bonds with aluminum and zinc. —Jake Yeston A stable compound featuring a beryllium-beryllium bond has been synthesized and characterized in solution and solid state.