Appearance Colorless liquid | ||
 | ||
Trimethylsilyl cyclopentadiene is an organosilicon compound with the chemical formula C8H14Si. This colorless compound is a liquid at room temperature. It is commonly used in the synthesis of metal cyclopentadienyl complexes.
Trimethylsilyl cyclopentadiene has been of theoretical interest as 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.
Synthesis
Trimethylsilyl cyclopentadiene is prepared by treating trimethylsilyl chloride (Me3SiCl) with sodium cyclopentadienide (NaC5H5) and distilling at 36 °C.
(CH3)3SiCl + NaC5H5 → C5H5Si(CH3)3 + NaCl