Cages versus Sheets: A Critical Comparison in the Size Range Expected for Methylaluminoxane (MAO)
Scott Collins, Mikko Linnolahti
Abstract
Abstract New cage models (MeAlO) n (Me 3 Al) m ( n =16, m =6 or 7) isomeric with previously reported sheet models for the principle activator found in hydrolytic MAO (h‐MAO) are compared at M06‐2X and MN15 levels of theory using density functional theory with respect to their thermodynamic stability. Reactivity of the neutrals or corresponding anions with formula [(MeAlO) 16 (Me 3 Al) 6 Me] − towards chlorination, and loss of Me 3 Al is explored while reactivity of the neutrals towards formation of contact‐ and outer‐sphere ion pairs from Cp 2 ZrMe 2 and Cp 2 ZrMeCl is examined. The results suggest on balance that a cage model for this activator is less consistent with experiment than an isomeric sheet model, although the latter are more stable based on free energy.