Sea-shell-like B31+ and B32: two new axially chiral members of the borospherene family

摘要

Since the discovery of the cage-like borospherenes D _(2d) B _(40) ~(?/0) and the first axially chiral borospherenes C _(3) / C _(2) B _(39) ~(?) , a series of fullerene-like boron clusters in different charge states have been reported in theory. Based on extensive global minimum searches and first-principles theory calculations, we present herein two new axially chiral members C _(2) B _(31) ~(+) ( I ) and C _(2) B _(32) ( VI ) to the borospherene family. B _(31) ~(+) ( I ) features two equivalent heptagons on the top and one octagon at the bottom on the cage surface, while B _(32) ( VI ) possesses two equivalent heptagons on top and two equivalent heptagons at the bottom. Detailed bonding analyses show that both sea-shell-like B _(31) ~(+) ( I ) and B _(32) ( VI ) follow the universal σ + π double delocalization bonding pattern of the borospherene family, with ten delocalized π bonds over a σ skeleton, rendering spherical aromaticity to the systems. Extensive molecular dynamics simulations show that these novel borospherenes are kinetically stable below 1000 K. The IR, Raman, and UV-vis spectra of B _(31) ~(+) ( I ) and B _(32) ( VI ) are computationally simulated to facilitate their future experimental characterizations.