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Title page for ETD etd-07162014-150837


Type of Document Master's Thesis
Author Martin, Katherine Ann
URN etd-07162014-150837
Title A Study of the Interaction of Polydentate Bases with Complexes of Electropositive Metals
Degree Master of Science
Department Chemistry
Advisory Committee
Advisor Name Title
Timothy P. Hanusa Committee Chair
Charles M. Lukehart Committee Member
Keywords
  • group 2 metals
  • alkaline earth metals
  • terpyridine
  • catalyst design
Date of Defense 2014-07-16
Availability unrestricted
Abstract
As part of a long-range project to develop inexpensive, earth-abundant alternatives to the use of rare-earth metals in catalysts, it was discovered that an unusual color is generated when solutions of Ca[1,3-(SiMe3)2C3H3]2(thf)2 and terypyridine are mixed in toluene. As the Ca2+ center lacks valence electrons, the deep blue coloration almost certainly arises from a ligand-to-metal charge transfer phenomenon. It was further determined that the color arises with Li+ and K+ centers in addition to Ca2+, and with the [1-(SiMe3)C3H3]– and [N(SiMe3)2]– anions as well. The key requirements thus appear to be a Group 1 or 2 metal center, terpyridine, a noncoordinating solvent, and a ligand that contains delocalized π-electrons, such as the bulky amido or allyl ligands used here. All available information indicates that the terpyridine compounds being synthesized exist in a dynamic equilibrium in solution, and the terpyridines are weakly bound to the metal.

Isolation of Ca(η1-C3H5)(η3-C3H5)(18-crown-6) demonstrates that it is possible to manipulate the hapticity of a ligand on a Group 2 center by adjusting the electron density on the metal with a suitably strong donor ligand. Further use of this capability could lead to the development of more active catalysts based on earth-abundant Group 2 metals.

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