Reconsidering the Structures of C2Al4− and C2Al5−

Abstract

AbstractThe study of C2Al4−/0 and C2Al5−/0 was conducted using anion photoelectron spectroscopy and quantum chemical computations. The present findings reveal that C2Al4− has a boat‐like structure, with a single C2 unit surrounded by four aluminum atoms. In contrast, the neutral C2Al4 species adopts a D2h planar structure with two planar tetracoordinate carbon (ptC) units, consistent with previous reports. Furthermore, the global minimum isomer of C2Al5− adopts a D3h symmetry, where the C2 unit interacts with five aluminum atoms. It was also found that a lower symmetry structure of C2Al5−, where all five aluminum atoms are located on the same side of the C2 unit, albeit slightly higher in energy compared to the D3h structure. These computations show that the D3h structure of C2Al5− is highly stable, exhibiting a large HOMO‐LUMO gap.