Syntheses, Crystal Structures, and Electronic Structure of the Boron Halides B9X9(X=Cl, Br, I)

Synthesis and Applications of Perfunctionalized Boron Clusters

“…More recent investigations of these clusters have resulted in the X-ray crystallographic analysis of the structures as well as further functionalization, however the halogenated derivatives remain the only perfunctionalized clusters in the B n H n (n = 7–11) series to date. 57,61–64 …”

The Zintl Ion [Pb10]2−: A Rare Example of a Homoatomic closo Cluster

“…For example, replacing the borane H atoms with more electronegative Cl (or Br) atoms in the 18-skeletalelectron cluster B 9 Cl 9 (or B 9 Br 9 ) leads to a tricapped trigonalprismatic structure (Figure 1, n = 9) that is predicted for 20 bonding skeletal electrons according to Wades rules. [4,5] Furthermore, a number of the ligand-free clusters of Group 14 elements have structures that deviate considerably from the expected polyhedral structures. [6,7] The structural characterization of numerous [E 9 ] 4À ions has revealed that in many cases distortions from the expected nido polyhedral structure (monocapped square antiprism) occur, as has also been observed for the electron-deficient clusters [E 9 ] 3À .…”

“…The lone-pair states of E n clusters are relatively higher in energy, with respect to the bonding skeletal orbitals, than are the external BÀH bonds in borane clusters. The chemical availability of the free electron pairs is demonstrated for E = Ge and Sn by the anions [{E[Cr(CO) 5 ]} 6 ] 2À , in which each E atom of the octahedral {E 6 } 2À cluster framework is coordinated to a {Cr(CO) 5 } group. [2,3] External ligands are also known to influence the number of bonding skeletal orbitals in the boranes.…”

The Surprising Structures of B8F12 and B10F12

“…Much is known about the structure of polyboron chlorides, bromides, and iodides [1,2] and of cluster compounds of other Group 13 elements derived from their monohalides. [3±5] However, with the exception of B 2 F 4 , [6] experimental structures of the polyboron fluorides are unknown.…”

“…If each BF 2 group is replaced by an H atom, this structure equates to B 4 H 4 (m-H) 2 . Organic derivatives of B 4 H 4 (m-H) 2 of type B 4 R 4 (m-H) 2 have been reported [16,17] and while the structures were not established by X-ray crystallography, there seems little doubt that they have a similar B 4 core to B 10 F 12 but with bridging H atoms across opposite edges of the tetrahedron. Nevertheless, such organoboron compounds and related derivatives of tetrabor-ane (6) [18,19] are much more electron rich and thus more stable than B 10 F 12 , which depends on relatively weak F À B pbonding to compensate for its electron deficiency.…”