Vibrational spectra of silsesquioxanes impregnated with the metallocene catalyst bis(η5-cyclopentadienyl)zirconium(IV) dichloride

FT-IR photoacoustic and Raman spectroscopy have been used to study the interactions between the metallocene catalyst, Cp2ZrCl2 (Cp = η5-C5H5), and two polyhedral oligomeric silsesquioxanes (POSS) supports. The first silsesquioxane support, POSSh, contains (β-hydroxyl)-tertiary amine groups, while in the second one, POSSu, these –OH groups have been converted into N-(p-toluyl) urethane groups. The vibrational spectra of the Cp2ZrCl2:POSSh and Cp2ZrCl2:POSSu samples show that the Cp2ZrCl2 catalyst reacts with the C–OH groups of POSSh and also interacts with N–H and >CO groups of POSSu. Furthermore, Cp2ZrCl2 can react with the Si–OH groups of the POSS supports and also interact with the O atoms that are bonded to the benzene rings and the N atoms of the tertiary amines in both silsesquioxanes. As a result of the interactions between Cp2ZrCl2 and the POSS supports, acidic species are generated. The Cp2ZrCl2:POSSh mass ratio seems to be an important parameter in the formation of Zr–O bonds and the acidic species.