Beyond the Active Site. Cp*ZrMe₃/Sulfated Alumina‐Catalyzed Olefin Polymerization Tacticity via Catalyst⋅⋅⋅Surface Ion‐Pairing

Abstract

Abstract Surface‐bound organometallic molecules have recently enabled the development of single‐site heterogeneous catalysts, advancing the atomic scale understanding and diversity of heterogeneous catalysis. Here we report that supporting Cp*ZrMe 3 ( Cat1 ) on acidic sulfated‐alumina (AlS) affords the surface catalyst Cat1/AlS , which was characterized by multi‐dimensional solid‐state NMR spectroscopies, and is active in ethylene homo‐ and copolymerizations, as well as propylene and 1‐hexene homopolymerizations. In contrast to propylene (or 1‐hexene) polymerization by homogeneous Cp*ZrMe 2 + B(C 6 F 5 ) 4 − which yields atactic polyolefins, Cat1/AlS promotes remarkable isotacticity with mmmm >95 %. Complementary DFT analysis argues that the restrictive local Cat1/AlS C 1 ‐symmetry favors activation and enchainment at the propylene re enantioface, promoting isotactic polymerization via a “back‐skip‐like” mechanism.