Date of Award

12-3-2001

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Chemistry

First Advisor

David T. Pierce

Abstract

In part I of this dissertation, a new set of sulfur containing pendant arm copper(II/I) macrocycles were synthesized to determine the effects of steric constraint on induced structural rearrangement. These new ligands have an N3S3 coordination sphere with nitrogens in a macrocyclic ring and pendant arms containing thiaether groups with varying terminal aliphatic groups. The complexes of these ligands with Cu(II) were characterized using Ultraviolet-visible (UV-Vis) spectroscopy, electronic spin resonance (ESR) spectroscopy and x-ray diffraction analysis. UV-Vis and ESR spectroscopy provided insight into different solution geometries of the copper complexes with respect to solvent and temperature. In general, as the temperature was lowered, the preferred structural geometry about the divalent copper center shifted from six coordinate towards five coordinate and even four coordinate structures. Single-crystal x-ray diffraction of several complexes provided solid state evidence of five coordinate and six coordinate geometries. Experimentation showed that the complex with least steric bulk, having a tris(methyl)thiaether pendant arm, always preferred six coordinate geometry at ambient temperatures regardless of solvent. All other complexes with greater pendant arm steric bulk showed some evidence of solvent dependent structure change. Part II of this dissertation introduces the development of an environmentally friendly sensor for the determination of organic pollutants in water. The sensor combined the solid phase microextraction (SPME) technique with the quartz crystal microbalance (QCM) for the determination of aliphatic and BTEX (benzene, toluene, ethylbenzene and xylenes) compounds in water samples. The method included monitoring a heterodyne frequency based on the fundamental resonance of a quartz crystal coated on one side with a hydrophobic stationary phase. When poly(dimethylsiloxane) was used for SPME of solution exposed to the coated face, aberrant, yet quantitative, response was observed by the QCM. A normal QCM response would constitute a drop in oscillation frequency when organic material extracted into the film. For the QCM-SPME sensor with OV-1, the oscillation frequency rose, suggesting that swelling of the film was the primary result of sorption.

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