AUTHOR=Gao Shu-Juan , Guo Jin-Chang , Zhai Hua-Jin 

TITLE=Boron Oxide B5O6− Cluster as a Boronyl-Based Inorganic Analog of Phenolate Anion

JOURNAL=Frontiers in Chemistry

VOLUME=Volume 10 - 2022

YEAR=2022

URL=https://www.frontiersin.org/journals/chemistry/articles/10.3389/fchem.2022.868782

DOI=10.3389/fchem.2022.868782

ISSN=2296-2646

ABSTRACT=Boron oxide clusters have structural richness and exotic chemical bonding. We report a quantum chemical study on binary B5O6− cluster, which is relatively oxygen-rich. Global structural search reveals a planar C2v (1A1) geometry as the global-minimum structure, featuring a heteroatomic hexagonal B3O3 ring as its core. The three unsaturated B sites are terminated by two boronyl (BO) groups and an O ligand, respectively. The B5O6− cluster can be faithfully formulated as B3O3(BO)2O−. This structure is in stark contrast to those of its predecessors, Cs B5O5− and Td B5O4−, both of which have a tetrahedral B center. Thus, there exists a major structural transformation in the B5On series upon oxidation, indicating intriguing competition between tetrahedral and heterocyclic structures. Chemical bonding analyses show weak 6π aromaticity in B5O6− cluster, rendering it a boronyl analog of phenolate anion (C6H5O) or boronyl boroxine. The calculated vertical detachment energy of B5O6− cluster is 5.26 eV at PBE0, which greatly surpasses the electron affinities of halogens (Cl: 3.61 eV), suggesting that the cluster belongs to superhalogen anions.