Trimethylsilyl cyclopentadiene is an organosilicon compound with the chemical formula C5H5Si(CH3)3. It exists as a colorless liquid. It is used in the synthesis of some metal cyclopentadienyl complexes and has attracted interest for its fluxional structure.
Trimethylsilyl cyclopentadiene is an example of a molecule that undergoes rapid sigmatropic rearrangement. Observations of trimethylsilyl cyclopentadiene using gas phase NMR spectroscopy show that the protons on the ring are chemically equivalent, indicated by a single peak. This phenomenon, an example of fluxionality, is explained by the migration of the silyl group from carbon-to-carbon, thereby giving the appearance of equivalent CH signals.
It has a refractive index (n20/D) of 1.471.
Synthesis Trimethylsilyl cyclopentadiene is prepared by the reaction trimethylsilyl chloride (Me3SiCl) with sodium cyclopentadienide (NaC5H5): (CH3)3SiCl + NaC5H5 → C5H5Si(CH3)3 + NaCl
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