Perfluoroalkyl derivatives silicon

Silicon.—-The simple volatile trifluoromethyl derivative CFa-SiFa has definitely been synthesized at last, and fully characterized spectroscopically it was obtained by sub-zero fluorination of the iodosilane CFa-SiFal with antimony trifluoride (AsFa or AgF may be used at 25 C) and shown partly to release its perfluoroalkyl group as fluoroform on contact with moisture and to give tetrafiuoroethylene (mainly) plus perfluorocyclopropane when pyrolysed. The latter decomposition occurs slowly at 78 °C (half-life at 100 °C and 50 Torr w 7 min) and presumably involves difluorocarbene ... 

The organometallic compounds prepared from alkali metal derivatives of metal carbonyls include compounds in which a transition metal of a metal carbonyl residue is cr-bonded to another atom such as a carbon atom in an alkyl, acyl, aryl, or perfluoroalkyl group, to the heavier congeners of carbon —silicon, germanium, tin, and lead—to mercury and gold which form unusually stable compounds, and even to other transition metals. The preparation and properties of all of these classes of compounds will be considered and, for the sake of completeness, a few related compounds prepared by routes other than those involving anionic metal carbonyl derivatives will be discussed. 

The temperatures quoted are those at which decomposition becomes appreciably rapid. Presumably metal fluorides are also formed in these decompositions but this has not been proven. A reaction which is apparently the reverse of these pyrolyses was mentioned above, namely the addition of platinum-fluorine bonds to tetrafluoroethylene 118). The thermal decomposition of perfluoroalkyl and polyfluoroalkyl derivatives of main group elements such as boron, silicon, or tin was mentioned in earlier sections of this chapter. Transfer of fluorine atoms from the side chains on heating was also a characteristic property. However, it is interesting to compare the reaction (97),... 

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