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STUDIES OF CHIRAL MOLECULES USING CHIROPTICAL SPECTROSCOPIES
by
Jian-Jung Pan
____________________________________________________________________
A Dissertation Presented to the
FACULTY OF THE GRADUATE SCHOOL
UNIVERSITY OF SOUTHERN CALIFORNIA
In Partial Fulfillment of the
Requirements for the Degree
DOCTOR OF PHILOSOPHY
(CHEMISTRY)
December 2007
Copyright 2007 Jian-Jung Pan
Object Description
| Title | Studies of chiral molecules using chiroptical spectroscopies |
| Author | Pan, Jian-Jung |
| Author email | jjpan@usc.edu |
| Degree | Doctor of Philosophy |
| Document type | Dissertation |
| Degree program | Chemistry |
| School | College of Letters, Arts and Sciences |
| Date defended/completed | 2007-08-01 |
| Date submitted | 2007 |
| Restricted until | Unrestricted |
| Date published | 2007-09-07 |
| Advisor (committee chair) | Stephens, Philip |
| Advisor (committee member) |
McKenna, Charles Petruska, John |
| Abstract | Recently, a new methodology based on the three chiroptical properties, namely vibrational circular dichroism (VCD), electronic circular dichroism (ECD) and optical rotation (OR), was developed toward determining the Absolute Configurations (ACs) of chiral molecules. This new methodology determines the AC of a chiral molecule via comparison of the ab initio Density Functional Theory (DFT) calculations of VCD, ECD or OR with the experimental results. Prior studies have shown that this method is quite straightforward and reliable, and readily applicable to a variety of chiral molecules. Although either one of the three chiroptical properties is capable of determining the AC by its own self, simultaneous applications of all three are more favorable and will undoubtedly increase the certainty of the AC determined. Our group has reported the first study of this kind and unambiguously determined the ACs of four cytotoxic sesquiterpene natural products. In an effort to further extend the applicability and demonstrate the reliability of this concerted method, we report here the determination of the ACs of several natural products with previously unknown ACs by the VCD, ECD and OR spectroscopies. They are schizozygane alkaloid: schizozygine; iso-schizozygane alkaloids: iso-schizogaline and iso-schizogamine; iridoids: plumericin, iso-plumericin and prismatomerin. In addition, the AC determination and conformational analysis of two chiral organic molecules, phenyl sulfoxides-d5 and 2-hydroxy-3-pinanone, using VCD spectroscopy are also reported.; In the second part of this thesis, the monomethyl-[16O, 17O, 18O]-phosphate and [16O, 17O, 18O]-thiophosphate have been synthesized and characterized by 31P and 17O NMR and by MS. Their ECD spectra have then been re-examined in order to evaluate the potential of ECD as a means to determine the ACs of these isotopically-chiral phosphate compounds. Measurable ECD was confirmed for monomethyl-[16O, 17O, 18O]-phosphate, although of somewhat weaker magnitude than previously reported. No significant ECD was detected for [16O, 17O, 18O]-thiophosphate. |
| Keyword | vibrational circular dichroism; electronic circular dichroism; optical rotation; density functional theory; isotopically chiral phosphate |
| Language | English |
| Part of collection | University of Southern California dissertations and theses |
| Publisher (of the original version) | University of Southern California |
| Place of publication (of the original version) | Los Angeles, California |
| Publisher (of the digital version) | University of Southern California. Libraries |
| Type | texts |
| Legacy record ID | usctheses-m808 |
| Contributing entity | University of Southern California |
| Rights | Pan, Jian-Jung |
| Repository name | Libraries, University of Southern California |
| Repository address | Los Angeles, California |
| Repository email | http://www.usc.edu/isd/libraries/services/ask_a_librarian/email/ |
| Filename | etd-Pan-20070907 |
| Archival file | uscthesesreloadpub_Volume23/etd-Pan-20070907.pdf |
Description
| Title | Page 1 |
| Contributing entity | University of Southern California |
| Full text | STUDIES OF CHIRAL MOLECULES USING CHIROPTICAL SPECTROSCOPIES by Jian-Jung Pan ____________________________________________________________________ A Dissertation Presented to the FACULTY OF THE GRADUATE SCHOOL UNIVERSITY OF SOUTHERN CALIFORNIA In Partial Fulfillment of the Requirements for the Degree DOCTOR OF PHILOSOPHY (CHEMISTRY) December 2007 Copyright 2007 Jian-Jung Pan |
