Electron-Rich Carboranes. Studies of a Stereochemically Novel System, (CH3)4C4B7H9, and 11-Vertex Arachno Cluster.
VIRGINIA UNIV CHARLOTTESVILLE DEPT OF CHEMISTRY
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The controlled degradation of CH34C4B8H8 I in 95 ethanol in air gives CH34C4B7H9 II. Electrophilic bromination of II produces 11-Br-CH34C4B7H8 III, which is shown in an X-ray diffraction study to have an open face compounds II and III can be described as 11-vertex arachno cages. Deprotonation of II with NaH in THF generates the monoanion CH34C4B7H8-IV from which the CH proton on the bridging group has been removed. Protonation of IV gives a new isomer of CH34C4B7H9 V, whose 11B and 1H FT NMR spectra indicate a substantially different cage geometry from that of II. The molecular structures of II-V and pathways for their interconversion are discussed inlight of NMR, ir, mass spectroscopic, and X-ray evidence. Crystal data for III BrC8B7H20 mol wt 271.84, space group P 1-bar, Z 2 a 7.7643, b 8.3525, c 12.3176A alpha 94.535, beta 95.415, gamma 120.515 deg V 678 A-cubed R 0.057 for 1404 independent reflections having F sub o - squared 3 sigma F sub o squared. Author
- Atomic and Molecular Physics and Spectroscopy