6533b7d4fe1ef96bd1261c36

RESEARCH PRODUCT

Complexes of titanium and zirconium containing a tridentate linked amido–cyclopentadienyl ligand with a soft donor group: synthesis, structure, and ethylene polymerization catalysis

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Abstract Group 4 metal complexes M(η5:η1-C5R4SiMe2NCH2CH2SMe)Cl2 (R=H, M=Ti; R=Me, M=Ti, Zr) containing the thioether-functionalized linked amido–cyclopentadienyl ligand were synthesized and characterized by 1H- and 13C-NMR spectroscopy, mass spectrometry, and elemental analysis. The crystal structures of the complexes Ti(η5:η1-C5H4SiMe2NCH2CH2SMe)Cl2 and Zr(η5:η1:η1-C5Me4SiMe2NCH2CH2SMe)Cl2 were determined by single-crystal X-ray diffraction studies. The titanium complex is a conventional three-legged piano-stool molecule without an intramolecular interaction between the sulfur donor group and the titanium center, whereas the zirconium complex adopts a trigonal bipyramidal structure, with the five-membered ring and the coordinating methylthio group in the apical positions. Reaction between the titanium dibenzyl Ti(η5:η1-C5Me4ZNCH2CH2SMe)(CH2Ph)2 (Z=SiMe2, CH2SiMe2) and B(C6F5)3 in C6D5Br resulted in the clean formation of the solvent-separated ion pair [Ti(η5:η1-C5Me4ZNCH2CH2SMe)(η2-CH2Ph)]+[(PhCH2)B(C6F5)3]−. The dichloro complexes M(η5:η1-C5Me4SiMe2NCH2CH2SMe)Cl2, when activated with methylaluminoxane, catalyzed the polymerization of ethylene with moderate activities. The phosphino-functionalized ligand C5Me4SiMe2NC6H4(PPh2)-2 was also coordinated at titanium and zirconium centers; NMR spectroscopic data inferred an intramolecular metal–phosphine interaction for these M{η5:η1-C5Me4SiMe2NC6H4(PPh2)-2}Cl2 complexes.