Structural similarity between boron oxide Bsubn/sub(BO)subn/subsup2–/sup and boron hydride Bsubn/subHsubn/subsup2–/sup dianions (i style="mso-bidi-font-style:normal"n/i = 4–12)

摘要

The boron oxide dianions Bsubn/sub(BO)subn/subsup2??/sup (i style="mso-bidi-font-style: normal"n/i = 4??2) are studied using DFT (B3LYP) method. Geometries of the global minima of Bsubn/sub(BO)subn/subsup2??/sup with i style="mso-bidi-font-style:normal"n/i = 4??2 are found to be analogous to those of boron hydrides. All boron oxides considered exhibit large HOMO-LUMO gaps and high vertical detachment energies. Similar to Bsubn/subHsubn/subsup2??/sup, the enhanced thermodynamic stabilities are established for Bsubn/sub(BO)subn/subsup2??/sup at i style="mso-bidi-font-style:normal"n/i = 6, 10 and 12. Due to the strength of BO bonds, oxidation of boron clusters thus consistently leads to formation of exohedral boronyls that in turns behave as substituents replacing the hydrogen atoms. This structural similarity allows the shape of boron oxides to be predicted from boron hydrides. Nevertheless, the BO bonds are expected to be the preferred reaction sites of boron oxides.