Location of Repository

The study and synthesis of Group 4 transition metal complexes in Ziegler-Natta catalysis

By Jonathan P. Corden

Abstract

In this thesis a study of Group 4 transition metal complexes and their possible use as Ziegler-Natta catalysts for alkene polymerisation is described.\ud \ud Several tetradentate Schiff base ligands have been synthesised and characterised, including some previously unreported examples. The products obtained from the reactions of Group 4 transition metal halides with the disodium salts of these ligands have been isolated and identified. The stereochemistry of these complexes is important for their use as Ziegler-Natta catalysts, and several complexes have been characterised by X-ray crystallography. [Ti(DMSALEN)Cl2], [Ti(PhSALEN)Cl2], [Ti(SLPNDM)Cl2] and [Zr(SLPNDM)Cl2(THF)] have a trans- geometry at the metal, and the complex [Ti(EtCycH)Cl2] has a cis- geometry. The remaining complexes have been studied by molecular modelling to establish a likely stereochemistry.\ud \ud The reactions of these dichloro complexes with trimethyl aluminium have been studied to gain insight into the chemistry involved in the polymerisation reactions. These reactions proceed with retention of the two chlorine atoms yielding complexes of the type [M(L)Cl2(AlMe3)2] (M = Ti, Zr; L =Schiff base). Side reactions also occur and the by-products [AlMe(EtSALEN)Al(Me)2][AlMeCl3] and [(AlMe2)2(AlMe3)2(EtSALEN)] have been isolated, and characterised by X-ray crystallography.\ud \ud Work was also carried out on the synthesis of complexes of the type (MCl2L) (M = Ti, Zr; L = tetra-azamacrocycle) by the reactions of MCl4 with the dilithium salt of the ligand. These complexes have been fully characterised and the molecular structure of the complex [Zr(omtaa)Cl2] determined by X-ray crystallography.\ud \ud Finally all these complexes have been tested as Ziegler-Natta catalysts for ethene polymerisation. A few selected complexes were also tested for their use in styrene polymerisation and found to be inactive

Topics: QD
OAI identifier: oai:wrap.warwick.ac.uk:2471

Suggested articles

Preview

Citations

  1. (1966). Acta Crystallogr., doi
  2. Compound [Ti(DMSALEN)C]2. THF] Formula Molecular weight Crystal system Space group a(A) b(A) c (A) a (°) V11) U (A) Temperature (K) Z D, (g cm 3) µ (mm-') min, emax (0) Index ranges Number of data collected
  3. Compound Formula Molecular weight Crystal system Space group a (A) b (A) c (A) a (°) P (°) Y (°) U (A) Temperature (K) Z D, (g cm"3) t (mm') ° emin, max Index ranges Number of data collected
  4. Compound Formula Molecular weight Crystal system Space group a (A) b (A) c (A) a (°) Y (°) U (A) Temperature (K) Z D, (g cm 3) µ (mm-') ° mini max Index ranges Number of data collected
  5. Compound Formula Molecular weight Crystal system Space group a (A) b (A) c(A) cc (°) ß (°) Y (°) U (A) Temperature (K) Z D, ý (g cm-3) µ (mm-') min, niax Index ranges Number of data collected
  6. Compound Formula Molecular weight Crystal system Space group a (A) b(A) c (A) a (°) P (°) y (°) U (A) Temperature (K) Z D, (g cm 3) µ (mm-') e min, eniax (0) Index ranges Number of data collected
  7. Compound Formula Molecular weight Crystal system Space group a (A) b(A) c(A) a (°) R (°) U (A) Temperature (K) Z D, (g cm 3) µ (mm-') min, max (0) Index ranges Number of data collected
  8. Compound Formula Molecular weight Crystal system Space group a (A) b(A) c(A) a (°) R (°) Y (°) U (A) Temperature (K) Z D, (g cm 3) it (mm-') min, emax (0) Index ranges Number of data collected
  9. Compound Formula Molecular weight Crystal system Space group a(A) b (A) c (A) a (°) R (°) Y (°) U (A) Temperature (K) Z D, (g cm-3) µ(mm') min, eniax (0) Index ranges Number of data collected
  10. Computational Chemistry", manual for HYPERCHEM version 4, Hypercube Inc.,
  11. (1991). Helvetica Chimica Acta, doi
  12. (1993). Inorg. doi
  13. (1975). Liebigs Aim. doi
  14. (1939). Metall. und Erz., doi
  15. (1974). Organometallic Chemistry of Titanium, Zirconium and Hafnium, doi
  16. Pan Zuohua and Zhang Zeying, Wuli Huaxue Xeubao (Acta Phys.
  17. (1968). The Chemistry of Titanium and Vanadium, Elsevier,

To submit an update or takedown request for this paper, please submit an Update/Correction/Removal Request.