Polymerization of methyl methacrylate catalyzed by mono-/bis-salicylaldiminato nickel(II) complexes and methylaluminoxane

Abstract

Two types of salicylaldiminato-based nickel complexes, mono-ligated Ni(II) complexes ([O-C 6 (9), Ar = 2,6-C 6 H 3 (i-Pr) 2 ) were synthesized and characterized by Fourier transform infrared spectroscopy (FT-IR), nuclear magnetic resonance (NMR), mass spectrography (MS) and elemental analysis (EA). In the presence of methylaluminoxane (MAO) as cocatalyst, all the nickel complexes exhibited high activities for the polymerization of methyl methacrylate (MMA) and syndiotactic-rich poly(methyl methacrylate) (PMMA) was obtained. The complexes with less bulky substituents on salicylaldiminato framework possessed higher activities, while with the same salicylaldiminato, the mono-ligated nickel complexes showed higher catalytic activity than bis-ligated ones.

Imino phenoxide complexes of group 4 metals: synthesis, structural characterization and polymerization studies

“…Ligands L1, L2 and L3 were prepared according to literature reported procedures. [36][37][38] CL, VL and rac-BL were dried over calcium hydride overnight and distilled fresh prior to use. Highly pure ethylene and propylene gas were purchased from Indogas, Bangalore, India.…”