Neutral zero-valent s-block complexes with strong multiple bonding

Abstract

The metals of the s block of the periodic table are well known to be exceptional electron donors, and the vast majority of their molecular complexes therefore contain these metals in their fully oxidized form. Low-valent main-group compounds have recently become desirable synthetic targets owing to their interesting reactivities, sometimes on a par with those of transition-metal complexes. In this work, we used stabilizing cyclic (alkyl)(amino)carbene ligands to isolate and characterize the first neutral compounds that contain a zero-valent s-block metal, beryllium. These brightly coloured complexes display very short beryllium-carbon bond lengths and linear beryllium coordination geometries, indicative of strong multiple Be-C bonding. Structural, spectroscopic and theoretical results show that the complexes adopt a closed-shell singlet configuration with a Be(0) metal centre. The surprising stability of the molecule can be ascribed to an unusually strong three-centre two-electron π bond across the C-Be-C unit.

Isolation of Cyclic(Alkyl)(Amino) Carbene–Bismuthinidene Mediated by a Beryllium(0) Complex

“…Recently, Braunschweig and co‐workers seminally reported the synthesis of a Be 0 compound, Be( Me2 CAAC) 2 . Though there were no reports of Be 0 being used as a reducing agent, we speculated that a Be 0 compound might facilitate the removal of the chloride atoms.…”

Carbones as Ligands in Novel Main‐Group Compounds E[C(NHC)2]2 (E=Be, B+, C2+, N3+, Mg, Al+, Si2+, P3+): A Theoretical Study

“…[48] This last speciesh as ad i-coordinated beryllium atom andt he cAAC ligandsa re arranged in al inear fashion. [48] This last speciesh as ad i-coordinated beryllium atom andt he cAAC ligandsa re arranged in al inear fashion.…”

“…[48] This last speciesh as ad i-coordinated beryllium atom andt he cAAC ligandsa re arranged in al inear fashion. [48] The bending angle C-E-C in 1E becomes smallerf rom beryllium to boron and carbonb ut then it remains constant for nitrogen. [48] The EDA-NOCV analysis suggested that Be(cAAC)p ossessesd ative bondsi nw hich the p back-donation from Be in the excited 2s 0 ,2p 2 state cAAC !…”

Dative bonds versus electron solvation in tri‐coordinated beryllium complexes: Be(CX)3 [X = O, S, Se, Te, Po] and Be(PH3)3 versus Be(NH3)3

“…Beryllium is one of the less studied elements of the periodic table. In spite of its rich and diverse chemical activity, the experimental interest is limited compared to its alkaline earth counterparts and other elements due to its high toxicity . Theory provides a safer alternative toward the comprehension of its bonding patterns .…”