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Date of Award

1993

Document Type

Thesis - Pacific Access Restricted

Degree Name

Master of Science (M.S.)

Department

Graduate School

First Advisor

Michael J. Minch

First Committee Member

Larry O. Spreer

Second Committee Member

Paul H. Gross

Abstract

This thesis includes NMR studies of free base meso-tetra(otolyl) porphyrin (TTP) and meso -tetraphenylporphyrin (TPP) and their dications protonated by trifluoroacetic acid (TFA). The chemical shift changes of the -NH resonance are very unusual and have never been reported. At the beginning of the titration, the N-H resonances broaden considerably but do not shift; when the ratio of [TFA]/[TTP] or [TFA]/[TPPf are over 2, the N-H resonances shift markedly to lower field by as much as 1.6 ppm. At acid levels well above the equivalence point, the NH resonances moves back to higher field. Moreover upon protonation the NH line of TTP becomes a complex multiplet which changes as a function of [TFA]/[TTP]. The NH line of TPP remains a singlet at all acid levels.

We also report here a way of isolating atropisomers of mesotetra( o -tolyl)porphyrin through HPLC by using an analytical C-18 bond pack reverse phase column eluted by a 1 %THF + 99%Me0H solvent combination. A preliminary study by HPLC was also carried out on ZnTTP(II) with aliquots of 2,6-dimethylpyridine, and the retention time of the separation decreased markedly, but this study needs to be repeated and improved.

TTP and TPP dications at two different acid levels were studied by VT-NMR, and the downfield shift of -NH resonance of TTP dications was more pronounced at higher temperatures than those of TPP dications.

Pages

130

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