Isospecific polymerization of sterically bulky α‐olefins catalyzed by zirconium(IV) complex possessing an [OSSO]‐type bis(phenolate) ligand

Abstract

AbstractDibenzyl zirconium(IV) complex (1), featuring an [OSSO]‐type bis(phenolate) ligand, served as a highly efficient pre‐catalyst for the polymerization of sterically bulky α‐olefins, such as vinyl cyclohexane (VCH) and 3‐methyl‐1‐butene (3‐MB). Upon activation with dried modified‐methylaluminoxane (dMMAO), the polymerization of VCH proceeded smoothly at 25°C to yield exclusively isotactic poly(VCH)s ([mm] >95%, Mw = 6500–19,400 g mol−1, PDI = 1.4), exhibiting good activity up to 924 g mmol(1)−1 h−1. The 1/dMMAO catalyst system also facilitated the polymerization of 3‐MB, producing colorless insoluble poly(3‐MB)s. DSC, TGA, and 13C CP‐MAS analyses showed the presence of highly isotactic microstructures in the resulting poly(3‐MB)s. Remarkably, the corresponding activity reached an impressive value of 898 g mmol(1)−1 h−1, surpassing that of previously reported homogeneous catalysts.