CaltechTHESIS
  A Caltech Library Service

Ruthenium olefin metathesis complexes : catalyst development and mechanistic studies

Citation

Anderson, Donde R. (2008) Ruthenium olefin metathesis complexes : catalyst development and mechanistic studies. Dissertation (Ph.D.), California Institute of Technology. http://resolver.caltech.edu/CaltechETD:etd-08142007-151304

Abstract

NOTE: Text or symbols not renderable in plain ASCII are indicated by [...]. Abstract is included in .pdf document. The field of olefin metathesis has grown to include organometallic chemists who strive to develop more efficient catalysts and to understand their mechanism of activity and decomposition, synthetic organic chemists who construct complex molecules utilizing existing catalysts and continually find challenging reactions in need of more efficient catalysts, and polymer chemists who utilize current catalysts to synthesize polymers with an ever-widening array of functional groups and structures in a controlled manner. This thesis describes the exploration of new ligands for olefin metathesis catalysts and the investigation of the model compounds of olefin metathesis reaction intermediates. Chapter 2 describes the synthesis, characterization, activity and kinetic selectivity of ruthenium olefin metathesis complexes bearing cyclic (alkyl)(amino)carbenes (CAACs). The activity of phosphine-free CAAC-ruthenium complexes is significantly affected by steric interactions. By decreasing the steric bulk of the ligand, a new catalyst with activity comparable to that of existing NHC-ruthenium (N-heterocyclic carbene) complexes has been synthesized. Additionally, these complexes exhibit unusual E/Z-diastereoselectivity and ethenolysis selectivity relative to previously studied NHC-ruthenium complexes. Chapter 3 describes the exploration of 3- and 6-membered carbenes as ligands for ruthenium olefin metathesis complexes. Stable silver-cyclopropenylidene adducts were synthesized and utilized as carbene transfer reagents in the presence of ruthenium precursors. Although good conversions were observed, isolation of cyclopropenylidene-ruthenium complexes was unsuccessful. Ruthenium complexes of 6-membered ‘borazine’-like carbenes were isolated, characterized and evaluated for ring-closing metathesis activity. Chapter 4 describes the development of a model system to study ruthenium-olefin complexes relevant to the mechanism of olefin metathesis. Upon addition of the ligand precursor 1,2-divinylbenzene to (H2IMes)(py2)(Cl)2Ru=CHPh (H2IMes = 1,3-dimesityl-4,5-dihydroimidazol-2-ylidene), two ruthenium-olefin adducts are formed. Based on [...] NMR spectroscopy experiments and X-ray crystallographic analysis, the solution phase and solid-state structure of these complexes is assigned. Exploration of the generality of these observations through variation of the N-heterocyclic carbene ligand and the ligand precursor are also presented. Appendix 1 describes the screening of transitional-metal salts and ligands for the non-oxidative hydration of styrene. Appendix 2 describes the investigation of a prior report of intramolecular olefin hydroalkoxylation with ruthenium, copper and silver salts. Appendix 3 describes the evaluation of chiral NHCs as ligands for ruthenium and rhodium hydrosilylation catalysts. Appendix 4 describes the investigation of tin(II) halides as ligands for ruthenium olefin metathesis catalysts. Appendix 5 contains X-ray crystallographic analysis parameters of the structures presented in this thesis.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:catalysis; olefin metathesis; ruthenium
Degree Grantor:California Institute of Technology
Division:Chemistry and Chemical Engineering
Major Option:Chemistry
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Grubbs, Robert H.
Thesis Committee:
  • Barton, Jacqueline K. (chair)
  • Stoltz, Brian M.
  • Bercaw, John E.
  • Grubbs, Robert H.
Defense Date:27 July 2007
Record Number:CaltechETD:etd-08142007-151304
Persistent URL:http://resolver.caltech.edu/CaltechETD:etd-08142007-151304
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:5247
Collection:CaltechTHESIS
Deposited By: Imported from ETD-db
Deposited On:08 Oct 2007
Last Modified:02 Dec 2014 22:28

Thesis Files

[img]
Preview
PDF (thesis2.pdf) - Final Version
See Usage Policy.

6Mb

Repository Staff Only: item control page