Lijia Liu, Xiaohua Wang, Xiaohui Kang, Lishuang Ma, Xuequan Zhang, Heng Liu
Iron complexes are renowned for promoting vinyl-selective polymerization of diene monomers, whereas systems capable of delivering high cis-1,4-selectivity remain relatively scarce. Herein, a series of α-diimine FeCl2 complexes featuring axial Fe...H-C anagostic interactions were synthesized and evaluated for 1,3-butadiene polymerization. Upon activation with AlR3/[Ph3C][B(C6F5)4], these complexes produce polybutadienes with much-enhanced cis-1,4-selectivity of up to 86%. Notably, the cis-1,4-selectivity remains largely insensitive to steric variations at distal ligand positions across the examined series (H vs tBu, cis-1,4-content of 81-84%), showing clear contrast to conventional α-diimine iron systems (cis-1,4-content <50%).