Vibrational spectra of silsesquioxanes impregnated with the metallocene catalyst bis(η 5-cyclopentadienyl)zirconium(IV) dichloride

Abstract

FT-IR photoacoustic and Raman spectroscopy have been used to study the interactions between the metallocene catalyst, Cp 2ZrCl 2 (Cp = η 5-C 5H 5), and two polyhedral oligomeric silsesquioxanes (POSS) supports. The first silsesquioxane support, POSS h, contains (β-hydroxyl)-tertiary amine groups, while in the second one, POSS u, these –OH groups have been converted into N-( p-toluyl) urethane groups. The vibrational spectra of the Cp 2ZrCl 2:POSS h and Cp 2ZrCl 2:POSS u samples show that the Cp 2ZrCl 2 catalyst reacts with the C–OH groups of POSS h and also interacts with N–H and >C O groups of POSS u. Furthermore, Cp 2ZrCl 2 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 Cp 2ZrCl 2 and the POSS supports, acidic species are generated. The Cp 2ZrCl 2:POSS h mass ratio seems to be an important parameter in the formation of Zr–O bonds and the acidic species.