Accession Number : ADA022992

Title :   Synthesis and Crystal Structure of a Novel Electron-Rich nido Trimetallocarborane.

Descriptive Note : Technical rept.,


Personal Author(s) : Salentine,Chris G. ; Strouse,Charles E. ; Hawthorne,M. Frederick

Report Date : 25 FEB 1976

Pagination or Media Count : 15

Abstract : Reaction of CB5Hg with nickelocene and sodium amalgam has yielded the first trimetallocarborane containing nickel, (C5H5Ni)3CB5H6. The complex can be formulated as a mixed-valence Ni(III)-Ni(III)-Ni(IV) system; the near infrared spectrum supports this formulation and indicates a considerable amount of mixed-valence charge transfer. The crystal structure has been determined from three-dimensional X-ray counter data. The complex crystallizes in the orthorhombic system, space group Pnma with a = 7.518(1) A, b = 14.740(2) A, c = 15.711(3) A, and Z = 4. Refinement of 1840 independent reflections with F(o) > 3 sigma (F(o)) has led to a final value of R = 3.16%. The electron-rich trimetallocarborane was found to adopt a novel nido geometry best described as a distorted monocapped square antiprism. Three nickel atoms and a boron atom compose the four-membered open face; the two equivalent Ni-Ni distances are 2.404(1) A. Non-bonded distances in the open face are Ni-Ni = 3.250(1) A, Ni-B = 2.991(5) A. The geometry is discussed in relation to electron counting rules for polyhedral heteroboranes.

Descriptors :   *Synthesis(Chemistry), *Crystal structure, *Carboranes, X ray diffraction, Nickel compounds

Subject Categories : Physical Chemistry

Distribution Statement : APPROVED FOR PUBLIC RELEASE