Planar B₄₁^- and B₄₂^- clusters with double-hexagonal vacancies

Area of Science:

• Computational Chemistry
• Materials Science
• Spectroscopy

Background:

• Following the discovery of B40 borospherene, interest grew in larger boron clusters.
• A key question is whether borospherene cages persist in larger boron structures.

Purpose of the Study:

• To investigate the structures and bonding of B41- and B42- boron clusters.
• To determine if borospherene cages are stable in these larger clusters.

Main Methods:

• Photoelectron spectroscopy (PES) was employed to study the electronic properties.
• Computational global minimum searches identified low-lying isomers.
• Chemical bonding analyses were performed to understand electronic structure.

Main Results:

• PES spectra for B41- and B42- showed complex features, indicating multiple isomers.
• For B41-, isomer II (double hexagonal vacancy) matched experimental data, with minor single vacancy isomers.
• For B42-, quasi-planar structure VIII (double hexagonal vacancy) was dominant, with other isomers contributing.
• Key isomers of B41- and B42- exhibit π aromaticity, similar to polycyclic aromatic hydrocarbons.

Conclusions:

• Quasi-planar structures with double hexagonal vacancies are favored for B41- and B42-.
• Borospherene cage structures are energetically unfavorable for these larger boron clusters.
• The findings challenge the simple persistence of borospherene cages in larger boron systems.