| Bromonium Ion |
Website Links For Ion |
Information AboutBromonium Ion |
| CATEGORIES ABOUT HALONIUM ION | |
| cations | |
|
Halonium ions were first postulated in 1937 by Roberts and Kimball to account for observed Diastereoselectivity in Halogenation of Alkene s. They correctly argued that if the initial reaction intermediate in bromination is the open-chain X--C-C+, rotation around the C-C Single Bond would be possible leading to a mixture of equal amounts of dihalogen Cis Isomer and trans isomer which is not the case. They also asserted that a positively charged halogen atom is Isoelectronic with oxygen and that carbon and bromine have comparable Ionization Potential s. In 1970 George A. Olah succeeded in preparing and isolating halonium Salt s by adding a methyl halide such as Methyl Bromide or Methyl Chloride in Sulfur Dioxide at -78°C to a complex of Antimony Pentafluoride and Tetrafluoromethane in sulfur dioxide. After evaporation of sulfur dioxide this procedure left crystals of CH3-X+-CH3SbF6-, stable at Room Temperature but not to moist. REFERENCES |
|
|