The shapes of hypoelectronic six-vertex anionic bare boron clusters: Effects of the countercations

Article type: Research Article

Authors: King, R. B. | Silaghi-Dumitrescu, I. | Lupan, A. | Kun, A.

Affiliations: Department of Chemistry, University of Georgia, Athens, Georgia, USA | Faculty of Chemistry and Chemical Engineering, Babeş-Bolyai University, Cluj-Napoca, Romania

Note: [] Corresponding author. E-mail: [email protected]

Abstract: RHF/6-31G(d) calculations have been carried out on the hypoelectronic six-vertex boron cluster anions B6z− (z = 6 and 4) as well as the corresponding alkali metal derivatives B6Mz (z = 6 and 4; M = Na and Li) and the isoelectronic B6H6 and B6H62+. Using such computational methods, the introduction of alkali metal counterions was found to have relatively little effect on the general structural patterns of the lowest lying structures for these clusters. However, introduction of external hydrogen atoms (i.e., protonation of B66− to B6H6 and B64− to B6H62+) was found to lead to more open structures in the boron network relative to the corresponding alkali metal derivatives because of the need to divert boron valence orbitals from skeletal bonding to covalent bonds to the external hydrogens. The preferred structures of a bicapped tetrahedron for 12 skeletal electron systems derived from B66− and a planar network of four fused triangles for 10 skeletal electron systems derived from B64− can be rationalized both by localized and delocalized chemical bonding models.

Keywords: Boron, Lithium, Boranes, Clusters

DOI: 10.1080/10241220600798435

Journal: Main Group Chemistry, vol. 4, no. 4, pp. 291-302, 2005