A concentric planar doubly π-aromatic B₁₉⁻ cluster.
Atomic clusters often show unique, size-dependent properties and have become a fertile ground for the discovery of novel molecular structures and chemical bonding. Here we report an investigation of the B₁₉⁻ cluster, which shows chemical bonding reminiscent of that in [10]annulene (C₁₀H₁₀) and [6]circulene (C₂₄H₁₂). Photoelectron spectroscopy reveals a relatively simple spectrum for B₁₉⁻, with a high electron-binding energy. Theoretical calculations show that the global minimum of B₁₉⁻ is a nearly circular planar structure with a central B₆ pentagonal unit bonded to an outer B₁₃ ring. Chemical bonding analyses reveal that the B₁₉⁻ cluster possesses a unique double π-aromaticity in two concentric π-systems, with two π-electrons delocalized over the central pentagonal B₆ unit and another ten π-electrons responsible for the π-bonding between the central pentagonal unit and the outer ring. Such peculiar chemical bonding does not exist in organic compounds; it can only be found in atomic clusters.
Department of Chemistry, Brown University, Providence, Rhode Island 02912, USA.
Wei
W
Huang
Alina P
AP
Sergeeva
Hua-Jin
HJ
Zhai
Boris B
BB
Averkiev
Lai-Sheng
LS
Wang
Alexander I
AI
Boldyrev
D001895:Boron / Q000737:chemistry*; D004583:Electrons; D008958:Models, Molecular; D008968:Molecular Conformation; D056951:Photoelectron Spectroscopy; D011789:Quantum Theory
D001895:Boron