Accession Number : ADA019418

Title :   Structural Consequences of Electron Hyperdeficiency. Synthesis and Crystal Structure of an Iron-Cobalt Metallocarborane Having Two Closed Polyhedra Fused Along an Edge.

Descriptive Note : Technical rept.,


Personal Author(s) : Maxwell,William M. ; Sinn,Ekk ; Grimes,Russell N.

Report Date : NOV 1975

Pagination or Media Count : 24

Abstract : A metallocarborane of novel structure, (CH3)4C4B8H8FeCo(Eta to the 5th power -C5H5), has been synthesized and structurally characterized from FTNMR, mass spectroscopic, infrared, and single crystal X-ray diffraction data. The dark green crystals are monoclinic, space group P2 sub 1, with two molecules per unit cell and a = 7.203(4) A, b = 14.77(2) A, c = 8.830(2) A, and beta = 99.7(1) degrees. (rho calcd = 1.38 g/cc, rho obsd = 1.38 g/cc). The structure was solved by the heavy-atom method and refined by full-matrix least-squares procedures to a final R value of 0.069 and R sub W = 0.081 for the 1657 reflectionions. The molecule contains a direct iron-cobalt bond and consists of two pentagonal bipyramidal units fused at a common iron atom with an additional BH group capping triangular faces on both polyhedra simultaneously. The structure is explained in terms of a shortage of two electrons in the cage framework, relative to the normal requirement for polyhedral clusters, which causes one BH group to adopt a capping location. These results are discussed in relation to the known structures of two osmium carbonyls and a diiron metallocarborane.

Descriptors :   *Carboranes, *Iron compounds, *Cobalt compounds, *Crystal structure, *Boron compounds, Metalorganic compounds, Electrons, Deficiencies, Solid state electronics, Nuclear magnetic resonance, X ray diffraction, Mass spectroscopy, Single crystals, Synthesis(Chemistry), Infrared spectroscopy, Physical properties, Chemical properties

Subject Categories : Organic Chemistry
      Atomic and Molecular Physics and Spectroscopy

Distribution Statement : APPROVED FOR PUBLIC RELEASE