A Heterogeneous Palladium Catalyst for the Polymerization of Olefins Prepared by Halide Abstraction Using Surface R Si Species.

The silylium-like surface species [ Pr Si][(R O) Al-OSi≡)] activates (N^N)Pd(CH )Cl (N^N=Ar-N=CMeMeC=N-Ar, Ar=2,6-bis(diphenylmethyl)-4-methylbenzene) by chloride ion abstraction to form [(N^N)Pd-CH ][(R O) Al-OSi≡)] (1). A combination of FTIR, solid-state NMR spectroscopy, and reactions with CO or vinyl chloride establish that 1 shows similar reactivity patterns as (N^N)Pd(CH )Cl activated with Na[B(Ar ) ]. Multinuclear C{ Al} RESPDOR and H{ F} S-REDOR experiments are consistent with a weakly coordinated ion-pair between (N^N)Pd-CH and [(R O) Al-OSi≡)]. 1 catalyzes the polymerization of ethylene with similar activities as [(N^N)Pd-CH ] in solution and incorporates up to 0.4 % methyl acrylate in copolymerization reactions. 1 produces polymers with significantly higher molecular weight than the solution catalyst, and generates the highest molecular weight polymers currently reported in copolymerization reactions of ethylene and methylacrylate.