Planar Tetracoordinate Carbons in Allene-Type Structures

Abstract

<p>The exhaustive exploration of the potential energy surfaces of CE<sub>2</sub>M<sub>2</sub> (E = Si-Pb, M = Li, and Na) revealed seven global minima containing a planar tetracoordinate carbon (ptC). The design was based on a π-localization strategy, resulting in a ptC embedded in a linear or a bent allene-type E=C=E motif. The magnetic response showed a σ-aromaticity in the bent E=C=E fragments. The bonding analysis indicated that the ptCs form C-E covalent bonds and C-M electrostatic interactions.<b></b></p>