An Early–Late Transition Metal Hybrid Analogue of Hexaborane(12)

On the 3D → 2D Isomerization of Hexaborane(12)

By following the intrinsic reaction coordinate connecting transition states with energy minima on the potential energy surface, we have determined the reaction steps connecting three-dimensional hexaborane(12) with unknown planar two-dimensional hexaborane(12). In an effort to predict the potential synthesis of finite planar borane molecules, we found that the reaction limiting factor stems from the breaking of the central boron-boron bond perpendicular to the C2 axis of rotation in three-dimensional hexaborane(12).

[(Cp2M)2B9H11] (M = Zr or Hf): early transition metal 'guarded' heptaborane with strong covalent and electrostatic bonding

We have isolated and structurally characterized two new transition metal complexes of the heptaborane, [(Cp₂M)₂B₉H₁₁] (Cp = η⁵-C₅H₅; M = Zr or Hf).

Among the series of stable closo-borate dianions, [B_nH_n]^2–, the X-ray crystallographic structure of [B₇H₇]^2– was determined only in 2011. To explore its chemistry and stability, we have isolated and structurally characterized two new transition metal complexes of the heptaborane, [(Cp₂M)₂B₉H₁₁] (Cp = η⁵-C₅H₅; M = Zr or Hf). The structures of [(Cp₂M)₂B₉H₁₁] contain a pentagonal bipyramidal B₇ core, coordinated by two {Cp₂M} and two {BH₂} units equatorially. Structural and spectroscopic characterizations and DFT calculations show that [(Cp₂M)₂B₉H₁₁] complexes are substantially more stable than the parent dianion, in either [B₇H₇]^2– or (ⁿBu₄N)₂[B₇H₇]. Our theoretical study and chemical bonding analyses reveal that the surprising stability of the two new heptaborane metal complexes is due to multi-center covalent bonds related to the two exo-{Cp₂M} units, as well as electrostatic interactions between the {Cp₂M} units and the B₇ core. The facile syntheses of the heptaborane metal-complexes will allow further exploration of their chemistry.

In search for new bonding modes of the methylenedithiolato ligand: novel tri- and tetra-metallic clusters

Photolysis ofarachno-[(Cp*Ru)₂(B₃H₈)(CS₂H)] in the presence of [Re₂(CO)₁₀] produced [(Cp*Ru)₂B₃H₅(CH₂S₂){Re(CO)₄}₂], with a planar 8-membered ring containing heavier transition metals and a main group element.