The Buildup of Eight-Vertex Tetrametallaborane Clusters: Bisdisphenoidal versus Tetracapped Tetrahedral Structures

Authors

  • Alexandru Lupan,

    Corresponding author
    1. Faculty of Chemistry and Chemical Engineering, Babeş-Bolyai University, Cluj-Napoca, Romania
    • Alexandru Lupan, Faculty of Chemistry and Chemical Engineering, Babeş-Bolyai University, Cluj-Napoca, Romania===

      R. Bruce King, Department of Chemistry, University of Georgia, Athens, Georgia 30602, USA===

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  • R. Bruce King

    Corresponding author
    1. Department of Chemistry, University of Georgia, Athens, Georgia 30602, USA
    • Alexandru Lupan, Faculty of Chemistry and Chemical Engineering, Babeş-Bolyai University, Cluj-Napoca, Romania===

      R. Bruce King, Department of Chemistry, University of Georgia, Athens, Georgia 30602, USA===

    Search for more papers by this author

Abstract

The experimental structures of Cp4M4B4H4 (M = Co, Ni) are both bisdisphenoids. However, in the cobalt compound, the metal atoms are located at the four degree 5 vertices, whereas in the nickel compound the metal atoms are located at the four degree 4 vertices. Density functional theory has shown these structures to be the lowest-energy structures by the substantial margins of around 23 and 15 kcal/mol for M = Co and Ni, respectively. The unknown analogous tetraferraborane Cp4Fe4B4H4 was predicted to have a different type of structure, namely a tetracapped tetrahedron, with the iron atoms at the four degree 6 vertices, similarly to the experimental structure of the valence isoelectronic Cp4Fe43-CO)4. The experimentally unknown Cp4M4B2H2 and Cp4M4 systems have also been optimized. Addition of BH units to either Cp4M4B2H2 or Cp4M4 to give the corresponding Cp4M4B4H4 derivatives has been predicted to be extremely exothermic.

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