Theoretical study on the stability of the novel B32 isomers and their metal-poly-boron MB32 cluster

Eight isomers of B32 cluster and metal-poly-boron MB32 complexes are examined at the B3LYP/6-31G(d) level to obtain the optimized geometries and vibrational frequencies. The expected B32 (Ih) isomer, proposed as conjugated polyhedron of C60, cannot be found as local energy minimum, owning to its large curvature strain and antiaromaticity. The tubular and quasi-planar B32 clusters are more stable than other three dimension (3D) structures. The calculated results show curvature strain, delocalized MOs and aromaticity play important role in the stability of B32 structures. What's more, some minima of MB32 (B32=tubular (1), quasi-planar (4), bowl (6) and cage (7); M=Li) are found, indicating bare B32 cluster can absorb a metal atom and form metal-poly-boron MB32 complexes. The interaction between metal atom and some B atom of B32 can be viewed as an ionic bond according to geometric, vibrational frequencies analysis, NBO calculation and the topological property ▽2ρ(r) calculation.