Electron-Rich Carboranes. Studies of a Stereochemically Novel System, (CH3)4C4B7H9, and 11-Vertex Arachno Cluster.
Abstract
The controlled degradation of (CH3)4C4B8H8 (I) in 95% ethanol in air gives (CH3)4C4B7H9 (II). Electrophilic bromination of II produces 11-Br-(CH3)4C4B7H8 (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 (CH3)4C4B7H8(-)(IV) from which the CH proton on the bridging group has been removed. Protonation of IV gives a new isomer of (CH3)4C4B7H9 (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 = 7.764(3), b = 8.352(5), c = 12.317(6)A; alpha = 94.53(5), beta = 95.41(5), gamma = 120.51(5) deg; V = 678 A-cubed; R = 0.057 for 1404 independent reflections having (F sub o) - squared > 3 sigma (F sub o) squared. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 1981
- Accession Number
- ADA094338
Entities
People
- David C. Finster
- Russell N. Grimes
Organizations
- University of Virginia