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Syntheses and reactions of polymer-bound molybdenum complexes and hydrogenolyses of an alknyl cobalt carbonyl cluster

Citation

Frommer, Jane Elizabeth (1981) Syntheses and reactions of polymer-bound molybdenum complexes and hydrogenolyses of an alknyl cobalt carbonyl cluster. Dissertation (Ph.D.), California Institute of Technology. http://resolver.caltech.edu/CaltechETD:etd-08052009-075725

Abstract

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Co3(CO)9CCH2C(CH3)3 (1) was prepared and its hydrogen- mediated decomposition was studied. 1 reacted with hydrogen in aromatic solvents (60°C, 2-7 atm H2) to yield three products: 3,3-dimethylbutene (2), 2,2-dimethylbutane (3), and 4,4- dimethylpentanal (4). The final ratio of alkene to alkane to aldehyde was approximately 2.5 : 1.5 : 1.0. Kinetic data collected from both NMR- and vpc-monitored experiments indicated first order decomposition of starting material 1 and a hydrogen pressure dependence for the rate of appearance of total products. Nearly total inhibition of the hydrogenation was observed in the presence of carbon monoxide (CO:H2, 3.7:3.7 atm, 60°C). However, at elevated temperatures (85°), under the same CO/H2 atmosphere, aldehyde (4) production became the predominant reaction pathway at the expense of earlier-formed olefin 2. Incorporation of independently added olefins in the hydrogenation of 1 suggested the intermediacy of olefin in aldehyde and alkane production.

A polystyrene-attached n[superscript 5}-cyclopentadienyl(tricarbony1)-hydridomolybdenum complex (P-6) was prepared and its reactions with several THF-soluble bases were investigated. Enolates of β-dicarbonyl compounds quantitatively deprotonated P-6, giving polymer-bound salts of the corresponding anion ([...]-Cp(CO)3Mo[...], P-7). Equilibration studies involving polymers P-6 and P-7 and their soluble monomeric analogues in THF demonstrated that little change in pKa was induced by binding the molybdenum hydride to the polymer. Even though the polymer-supported partners in these experiments were not soluble and therefore rendered the reactions heterogeneous, the systems adhered reasonably well to conventional equilibrium behavior, as exhibited by a simple equilibrium analysis which yielded effectively constant Keq values. A polymer-bound carboxylic acid (P-1) and its conjugate base (P-2) also displayed essentially conventional equilibrium dynamics.

Item Type:Thesis (Dissertation (Ph.D.))
Degree Grantor:California Institute of Technology
Division:Chemistry and Chemical Engineering
Major Option:Chemistry
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Bergman, Robert G.
Thesis Committee:
  • Unknown, Unknown
Defense Date:22 August 1980
Record Number:CaltechETD:etd-08052009-075725
Persistent URL:http://resolver.caltech.edu/CaltechETD:etd-08052009-075725
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:3018
Collection:CaltechTHESIS
Deposited By: Imported from ETD-db
Deposited On:05 Aug 2009
Last Modified:26 Dec 2012 02:56

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