Author

Peter Nickias

Document Type

Thesis - Open Access

Award Date

1981

Degree Name

Master of Science (MS)

Department

Chemistry

First Advisor

James J. Worman

Abstract

In the past decade some new interpretations of orbital interactions in small rings have resulted from the observations of valence shell ionization potentials. These ionization potentials were obtained from a technique known as photoelectron spectroscopy, most often referred to as PES. Photoelectron spectroscopy is the branch of electron spectroscopy in which the ionizing process is brought about by vacuum ultraviolet radiation. It is thus concerned with the ejection of electrons from valence orbitals of molecules. What PES does is measure the binding energies of electrons in a molecule by determining the kinetic energies of these electrons when they are ejected from the molecule by the impact of (usually} monochromatic radiation. This phenomena can be expressed by the relationship: (energy units are in electron volts) E1p - ionization potential, Es - energy of radiation source, EK·E - kinetic energy of ejected electron. By use of the values for the ionization potentials, band shapes and the number of ionizations, a molecular orbital picture along with the energy levels of the desi red molecule can be constructed. Through PES, several types of molecular interactions have come to light. Of particular interest to us, is the through bond or circumannular interaction, observed between the lone pair~ of the oxygen atoms in 2,2,4,4 tetramethyl-1,3-cyclobutandione, interacting through the orbitals of appropriate symmetry, on the carbon atoms in the ring and what is referred to as a transannular or through space 1,3 p-pi interaction. Both interactions mentioned, have the potential of occurring in the cyclobutadione molecule and related systems. Spectral properties other than PES, such as ultraviolet, infrared, and NMR can give information relating to the structures and eventually to the orbital interactions in small ring systems. Such studies have been previously reported in our labs. The purpose of this work is to evaluate the magnitude of circumannular versus transannular interactions in specific heterocyclic systems. In order to accomplish this, the synthesis of thietan-3-one, azetidine 3-one, oxetan-3-one, and related heterocyclic systems were to be attempted and their spectral properties examined.

Format

application/pdf

Publisher

South Dakota State University

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