Boron monoxide dimer as a building block for boroxine based buckyballs and related cages: a theoretical study.

B3LYP/DZP level calculations are used to predict B2O2 cage oligomers, which are constructed from polyhedra by locating their B-B bonds at edge midpoints and three oxygen atoms at each degree 3 vertex. The stability of such cage oligomers depends highly on the B2nOn (n = 3, 4, 5) cavities corresponding to the polyhedral faces. All such polyhedral oligomers are found to have larger cohesive energies (Ec's) than corresponding planar structures, except for the smallest (B2O2)6 tetrahedron with extremely high strain arising from the four B6O3 cavities forming the tetrahedron faces. Promising (B2O2)n cages with the highest cohesive energies include pentagonal dodecahedral (B2O2)30 (c-B30) with B10O5 cavities, truncated octahedral (B2O2)36 (t-B36-2) with B8O4 cavities, and truncated icosahedral (B2O2)90 (t-B90) with B10O5 cavities. However, smaller (B2O2)n oligomers are also expected to exhibit cage structures having B8O4 or even B6O3 cavities because of their large Ec(s).