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Synthesis and reactivity of transition metal methylidene complexes


Finch, William C. (1986) Synthesis and reactivity of transition metal methylidene complexes. Dissertation (Ph.D.), California Institute of Technology.


The reaction of metal oxo complexes with methylenation agents, "Cp_2TiCH_2" and CH_2PPh_3, was investigated as a means to generate new transition metal methylidene complexes. With "Cp_2TiCH_2", only when the oxo complex has ancillary ligands of the proper electronic and steric characteristics, as in WO(CH_2XMe_3)_4(X = C, Si), is clean reaction observed producing µ-O-µ-CH_2 complexes. Otherwise the many reaction pathways available to the Cp_2TiCH_2 fragment lead to complex reaction mixtures. The oxo ligand is inert to attack by CH_2PPh_3 which instead acts as a powerful alkylating agent in the transition metal systems investigated. The effect of cyclopentadienyl ring substitution on the reactivity of titanocene metallacyclobutanes was also investigated. The observed decrease in reactivity of these compounds with increasing methyl substitution of their cyclopentadienyl rings is related to the increasing destabilization of the transition state between metallacycle and methylidene-olefin complex upon substitution. This destabilization arises from the "reductive" nature of the formation of methylidene-olefin complex from metallacycle.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:Chemistry
Degree Grantor:California Institute of Technology
Division:Chemistry and Chemical Engineering
Major Option:Chemistry
Thesis Availability:Restricted to Caltech community only
Research Advisor(s):
  • Grubbs, Robert H.
Thesis Committee:
  • Unknown, Unknown
Defense Date:14 May 1986
Record Number:CaltechTHESIS:10062009-112330268
Persistent URL:
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:5292
Deposited By: Tony Diaz
Deposited On:07 Oct 2009 16:17
Last Modified:26 Dec 2012 03:17

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