Skip to content Skip to navigation
University of Warwick
  • Study
  • |
  • Research
  • |
  • Business
  • |
  • Alumni
  • |
  • News
  • |
  • About

University of Warwick
Publications service & WRAP

Highlight your research

  • WRAP
    • Home
    • Search WRAP
    • Browse by Warwick Author
    • Browse WRAP by Year
    • Browse WRAP by Subject
    • Browse WRAP by Department
    • Browse WRAP by Funder
    • Browse Theses by Department
  • Publications Service
    • Home
    • Search Publications Service
    • Browse by Warwick Author
    • Browse Publications service by Year
    • Browse Publications service by Subject
    • Browse Publications service by Department
    • Browse Publications service by Funder
  • Help & Advice
University of Warwick

The Library

  • Login
  • Admin

Half-sandwich group 4 salicyloxazoline catalysts

Tools
- Tools
+ Tools

Coles, Stuart R., Clarkson, Guy J., Gott, Andrew L., Munslow, Ian J., Spitzmesser, Stefan K. and Scott, Peter (2006) Half-sandwich group 4 salicyloxazoline catalysts. Organometallics, Volume 25 (Number 26). pp. 6019-6029. doi:10.1021/om060687h

Full text not available from this repository, contact author.
Official URL: http://dx.doi.org/10.1021/om060687h

Request Changes to record.

Abstract

A new class of zirconium and hafnium half-sandwich complexes bearing Cp* and salicyloxazolinato ( L) ligands has been prepared by salt elimination and protonolysis routes. The analogous Cp and indenyl compounds are generally inaccessible, as are the titanium compounds. The molecular structures of four examples [Cp*MLX2] (variously M = Zr, Hf; X = Cl, Me) reveal chiral-at-metal structures which persist in solution, according to variable-temperature NMR studies; Delta G(298)(double dagger) for the racemization process was found to be ca. 75 kJ mol(-1). Treatment of these compounds with MAO, [Ph3C][B(C6F5)(4)], or [PhNMe2H][B(C6F5)(4)] leads to catalysts for alkene polymerization, the nature of which depends on the cocatalyst chosen. The anilinium salt smoothly produces a single chiral species, [Cp*ZrLMe][B(C6F5)(4)], detected also by H-1 NMR spectroscopy, which is a highly active single-site catalyst for polymerization of ethene ( and less active for copolymerization of ethene/hexene). The trityl activator produces the same catalyst and at least one other catalytically competent species, as evidenced by NMR spectroscopy and polymer modality. The use of MAO leads to a less well-defined catalyst system. The steric demand of the salicyloxazoline ligand affects the catalyst performance significantly, and computational studies show that access of ethene to either of two inequivalent coordination sites is restricted. This stability of the species [Cp*ZrLMe](+) with respect to addition appears to be the limiting factor for catalytic activity. Catalyst stability is addressed, and the steric and electronic factors affecting this are consistent with a mechanism of catalyst death by salicyloxazoline ligand loss.

Item Type: Journal Article
Subjects: Q Science > QD Chemistry
Divisions: Faculty of Science > Physics
Journal or Publication Title: Organometallics
Publisher: American Chemical Society
ISSN: 0276-7333
Official Date: 18 December 2006
Dates:
DateEvent
18 December 2006UNSPECIFIED
Volume: Volume 25
Number: Number 26
Number of Pages: 11
Page Range: pp. 6019-6029
DOI: 10.1021/om060687h
Status: Peer Reviewed
Publication Status: Published

Data sourced from Thomson Reuters' Web of Knowledge

Request changes or add full text files to a record

Repository staff actions (login required)

View Item View Item
twitter

Email us: publications@live.warwick.ac.uk
Contact Details
About Us