Thermally robust bis(imino)pyridyl iron catalysts for ethylene polymerization: Synergy effects of weak π-π interaction, steric bulk, and electronic tuning

Abstract

A series of “half-sandwich” bis(imino)pyridyl iron complexes with a substituted 8-(p-X-phenyl)naphthylamine (X = OMe, Me, CF₃) was designed and synthesized by combining weak π-π interaction with steric and electronic tunings. The weak noncovalent π-π interaction as well as the steric and electronic effects of bis(imino)pyridyl iron complexes were identified by experimental analyses and calculations. The roles of weak π-π interaction, steric bulk, and electronic tuning on the ethylene polymerization performance of bis(imino)pyridyl iron catalysts were studied in detail. The combination of π-π interaction with steric and electronic tunings can access to thermally stable bis(imino)pyridyl iron at 130 °C.