Raman and IR spectra of the unstable ionic species potassium trimethylsilanolate: The role of the counterion in its theoretical interpretation

We have accomplished a reliable assignment of the vibrational spectra of the ionic species potassium trimethylsilanolate, which is unstable towards hydrolysis and self‐condensation, by means of the combined use of experimental data and theoretical density functional theory (DFT) calculations. We report the first record of the Raman spectrum of the pure solid. Additionally, we have newly recorded its IR spectrum in Nujol mull and for the first time in Fluorolube mull, completing the experimental data available in the literature about this chemical species. Further, in order to discuss the convenience of including the counterion in the model used for the quantum‐mechanical calculations of its vibrational spectra, we have compared the performance of three different theoretical models, namely, the isolated trimethylsilanolate anion, a theoretical monomer of potassium trimethylsilanolate and a simplified ionic cluster model based on its crystalline structure. Copyright © 2007 John Wiley & Sons, Ltd.