2. 1 Macromolecular Science and Engineering Wednesday June 2 MA3 Regatta Advances In Olefin Polymerization Organizer - H. Zahalka Chair - J. Soares 14:00-14:30 00995 A Density Functional Study on Ion-Pair Formation in Group 4 Metallocene and Related Olefin Polymerization Catalysts Ziegler T., Chan M., Vanka K., Pye C.

3. 2 A Density Functional Study on Activation and Ion-Pair Formation in Group IV Metallocene and Related Olefin Polymerization Catalysts Mary S.W. Chan, Kumar Vanka, Cory C. Pye and Tom Ziegler Department of Chemistry, University of Calgary Calgary, Alberta Canada T2N 1N4

6. 5 Major Sections Mono- cyclopentadienyl Constrained Geometry Bis- cyclopentadienyl M = Ti or Zr R = methyl group à Reactions of the contact ion-pair à Activation of various catalyst precursors by the co-catalyst B(C 6 F 5 ) 3 Areas for In-depth Study Catalyst Systems for In-depth Study

7. 6 Enthalpy Change of Methide Abstraction ∆H M = Ti -12.2 kcal/mol M = Zr -14.9 kcal/mol ∆H M = Ti -14.4 kcal/mol M = Zr -17.5 kcal/mol ∆H M = Ti -16.3 kcal/mol M = Zr -19.1 kcal/mol Activation by a -catalyst Activation by a Co-catalyst

8. 7 Activation by a Co-catalyst Charge Analysis of Ligands and Functional Groups in the Neutral Precursor and Ion-Pair + Cyclopenta dienyl 0.02 Ti 0.41 methyl-0.15 methyl-0.13 B 0.11 C 6 F 5 -0.04 C 6 F 5 -0.03 C 6 F 5 -0.04 Cyclopenta dienyl 0.13 Ti 0.43 methyl-0.07 Methyl-0.07  -methyl-0.03 B-0.01 C 6 F 5 -0.09 C 6 F 5 -0.13 C 6 F 5 -0.15

9. 8 Activation by a Co-catalyst Effect of Alkyl Substitution on the Constrained Geometry Catalyst ∆H ∆HTotalTotalChange in R gas phase COSMOCharge inCharge inCharge (kcal/mol)(kcal/mol)NeutralIon-PairDensity H-13.9-14.4-0.21-0.170.04 Methyl-16.1-16.4-0.19-0.130.06 Isopropyl-16.9-17.0-0.18-0.120.06 tert-Butyl-18.4-18.0-0.19-0.100.09

10. 9 Activation by a Co-catalyst Effect of Methyl Substitution on Cp Rings ∆H (kcal/mol) Substitution on Cp gas phase COSMOExperimental a H-19.1-19.1-23.1 1,2-Dimethyl-23.8-24.0-24.3 Pentamethyl-27.5-27.8-36.7 a Obtained from: Deck, P.A.; Beswick, C.L.; Marks, T.J. J. Chem. Soc. 1998, 120, 1772.

14. 13

15. 14

16. 15

17. 16

18. 17

19. 18

20. 19

21. 20

22. 21

23. 22

24. 23

25. 24

26. 25

27. 26

28. 27

29. 28

30. 29Introduction Possible Reactions of the Contact Ion-Pair

31. 30 Reactions of the Contact Ion-Pair Toluene Complexed Ions and Ion-Pairs from the CpZrMe 3 Precursor

32. 31 Reactions of the Contact Ion-Pair Toluene Complexed Ions and Ion-Pairs from the H 2 SiCp(NH)ZrMe 2 Precursor

33. 32 Reactions of the Contact Ion-Pair Toluene Complexed Ions and Ion-Pairs from the Cp 2 ZrMe 2 Precursor

34. 33 Reactions of the Contact Ion-Pair Olefin Complexed Ions and Ion-Pairs from the CpZrMe 3 Precursor

35. 34 Reactions of the Contact Ion-Pair Olefin Complexed Ions and Ion-Pairs from the H 2 SiCp(NH)ZrMe 2 Precursor

36. 35 Reactions of the Contact Ion-Pair Olefin Complexed Ions and Ion-Pairs from the Cp 2 ZrMe 2 Precursor

37. 36 Reactions of the Contact Ion-Pair Initial Stages of Polymerization for CpMMe 3 and H 2 SiCp(NH)MMe 2 Systems

38. 37 Reactions of the Contact Ion-Pair Initial Stages of Polymerization for Cp 2 MMe 2 Systems

39. 38 Electronic factors play a predominant role in determining the enthalpy change of methide abstraction to form a contact ion-pair. Mechanism of olefin complexation dependant on the structure of the catalyst precursor and solvent. Mono-cyclopentadienyl and constrained geometry catalysts show a strong tendency to co-ordinate with toluene The steric bulk of the bis-cyclopentadienyl catalysts prevent optimal co- ordination with toluene and makes olefin complexation more favorable Conclusions

40. 39 Work in Progress Search for the structure of resting state(s) incorporating the counter ion Molecular dynamics simulation of olefin uptake and insertion from the contact ion-pair

41. 40 Future Work To study the influence of the counter ion on the propagation steps of the polymerization process To study the influence of the counter ion on chain termination steps of the polymerization process To study the role of the counter ion with other catalysts precursors such as the Brookhart or the McConville systems To study the influence of other solvents (non-aromatic) on ion-pair formation and dissociation To design new precatalysts and co-catalysts systems

43. 42

44. 43

45. 44