Solid state ¹³C NMR characterisation study on fourth generation Ziegler-Natta catalysts

In this study, solid state ¹³C NMR spectroscopy was utilised to characterize and identify the metal–ester coordination in active fourth generation (phthalate) Ziegler–Natta catalysts. It is known that different donors affect the active species in ZN catalysts. However, there is still limited data available of detailed molecular information how the donors and the active species are interplaying. One of the main goals of this work was to get better insight into the interactions of donor and active species. Based on the anisotropy tensor values (δ₁₁, δ₂₂, δ₃₃) from low magic-angle spinning (MAS) ¹³C NMR spectra in combination with chemical shift anisotropy (CSA) calculations (δ_aniso and η), both the coordinative metal (Mg/Ti) and the symmetry of this interaction between metal and the internal donor in the active catalyst (MgCl₂/TiCl₄/electron donor) system could be identified.