Date of Award

1984

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Chemistry

Abstract

This work was a study of Lewis acid-base interactions in a series of complexes formed by the reaction of a series of Group IIIA metal alkyls with some simple amine N-oxides. The Group IIIA metal alkyls used in this work were trimethylaluminum, triethylaluminum, tripropylaluminum, tributylaluminum, triisobutylaluminum, trimethylgallium, triethylgallium, tripropylgallium, tributylgallium, triisobutylgallium, trimethylindium, triethylindium, tripropylindium, tributylindium, and triisobutylindium. The amine N-oxides used were pyridine-N-oxide, 2-picoline-N-oxide, 3-picoline-N-oxide, and 4-picoline-N-oxide. Elemental analysis, mass spectrometry, infrared spectroscopy, visible-ultraviolet spectroscopy, nuclear magnetic resonance spectroscopy, and cryoscopic molecular weight determinations were used to study these complexes. Nuclear magnetic resonance was the most useful method for determining the strength of the acid-base interactions. It was found that both steric effects and inductive electronic effects influenced the strength of the acid-base interaction. For the metal alkyls, steric effects were most likely to influence the strength of the interaction when large alkyl groups were attached to a small metal atom. For the amine N-oxides, steric effects were most likely when 2-picoline-N-oxide was used in complex formation. The chemical shifts of the amine N-oxide hydrogen atoms were plotted versus the covalent radius of the central metal atom and versus the atomic number of the central metal atom and the correlation was discussed. The chemical shifts of the alkyl group hydrogens were plotted versus the pK(,a) values of the amine N-oxide conjugate acids and the correlations were discussed.

Pages

284

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