A Neutral Beryllium(I) Radical

Abstract

The reduction of a cyclic alkyl(amino)carbene (CAAC)‐stabilized organoberyllium chloride yields the first neutral beryllium radical, which was characterized by EPR, IR, and UV/Vis spectroscopy, X‐ray crystallography, and DFT calculations.

Behavior of Lewis Bases toward Diphenylberyllium

“…In contrast to the ubiquity of organomagnesium reagents, organoberyllium chemistry is relatively unexplored due, at least in part, to the perceived toxicity of this element. − Indeed, although organoberyllium complexes were prepared as early as the 1920s, − the field has subsequently been relatively devoid of methodical, fundamental beryllium research. Recently, there has been renewed interest in the organometallic chemistry of beryllium, driven by a desire to understand the biotoxicity mechanisms of this element and exploit its unique electronic properties for chemical transformations. − Within the past five years, the first compounds containing formally zero- and monovalent beryllium centers, in addition to the first BeC and BeN bonds have all been reported. − …”

Access to a Labile Monomeric Magnesium Radical by Ball‐Milling

“…Electron transfer from metal to the CAAC ligand is supported by a spin density analysis. For the metals in [Be I (CAAC) 2 + ], (CAAC‐H)Be(CAAC), Mulliken spin densities of 0.38 and 0.23 were reported (BP86‐D3(BJ)/def2SVP) [25, 26] . Using the same method, the spin density on Mg in 2 is 0.19.…”

“…These observations set the scene for the challenging isolation of highly reactive Mg I radicals. Key to the isolation of such a species is a cyclic (alkyl)(amino)carbene ligand (CAAC), which is well‐known for stabilization of low‐valent metals [23–26] . The Be‐CAAC contacts in Be 0 (CAAC) 2 , [Be I (CAAC) 2 + ] and (CAAC‐H)Be I (CAAC) are described as a synergistic bond involving C→Be σ‐donation and strong Be→C π‐backdonation; CAAC‐H = CAAC+H − [24–26] .…”

Recent Advances in the Domain of Cyclic (Alkyl)(Amino) Carbenes

“…Additionally, neutral Be I radical (223) has also been stabilized by cAAC (Figure 27). [294] The Be I radical complex was synthesized by reduction of organoberyllium chloride and structure was confirmed by single-crystal XRD and EPR spectroscopy.…”