Direct observation of a cationic ruthenium complex for ethylene insertion polymerization

• Published in: Chemical science (Cambridge) Vol. 4; no. 7; pp. 2902 - 2906
• Main Authors: Camacho-Fernandez, Miguel A, Yen, Max, Ziller, Joseph W, Guan, Zhibin
• Format: Journal Article
• Language: English
• Published: 01.06.2013
• Subjects: Activation; Activation analysis; Cationic; Ethylene; Insertion; Olefins; Polymerization; Ruthenium
• ISSN: 2041-6520; 2041-6539
• DOI: 10.1039/c3sc50676b

We report here the first direct observation of a cationic ruthenium complex catalyzing ethylene insertion polymerization. An arene-tethered ruthenium complex ( eta super(6)-C sub(6)H sub(5)(CH sub(2)) sub(3)SCH sub(3)RuCl sub(2)) (3) was synthesized and shown to be able to catalyze ethylene polymerization upon activation with AlMe sub(2)Cl. For mechanistic studies, we synthesized the homologous dimethylated eta super(6)-C sub(6)H sub(5)(CH sub(2)) sub(3)SCH sub(3)Ru(CH sub(3)) sub(2) (4) complex, which upon activation with the Brookhart acid ([H(Et sub(2)O) sub(2)] super(+) [BAr' sub(4)] super(-)) was also active for ethylene insertion polymerization. super(1)H-NMR and mass spectrometry (MS) studies provide direct evidence for a ruthenium cationic [ eta super(6)-C sub(6)H sub(5)(CH sub(2)) sub(3)SCH sub(3)Ru(oligomer)] super(+) complex as the active species during polymerization. This has unambiguously shown for the first time a ruthenium complex as the active species for catalyzing olefin insertion polymerization.