Issue Date: October 27, 2008
Si–F Bond Strength
WHILE THE WORK described in "Breaking C–F Bonds" (C&EN, Sept. 1, page 13), is very nice, especially lengthening the lifetime of the catalyst, the driving force of this reaction is really the extreme silicon-fluorine bond strength of 582 kJ/mol; the silicon-hydrogen bond strength is approximately 323 kJ/mol.
If I recall correctly, the silicon-fluorine single bond is the strongest single-bond strength for any pair of atoms. I would be hard-pressed to say the effect is completely that of a silylium Lewis acid but is probably more due to the extreme silicon-fluorine affinity.
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