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CATALYTIC C-H ACTIVATION BY CYCLOMETALLATED
IRIDIUM HYDROXO COMPLEXES IN AQUEOUS MEDIA
by
Steven Karl Meier
A Dissertation Presented to
FACULTY OF THE GRADUATE SCHOOL
UNIVERSITY OF SOUTHERN CALIFORNIA
In Partial Fulfillment of the
Requirements for the Degree
DOCTOR OF PHILOSOPHY
(CHEMISTRY)
August 2008
Copyright 2008 Steven Karl Meier
Object Description
| Title | Catalytic C-H activation by cyclometallated iridium hydroxo complexes in aqueous media |
| Author | Meier, Steven Karl |
| Author email | meiersk78@yahoo.com |
| Degree | Doctor of Philosophy |
| Document type | Dissertation |
| Degree program | Chemistry |
| School | College of Letters, Arts and Sciences |
| Date defended/completed | 2008-06-03 |
| Date submitted | 2008 |
| Restricted until | Unrestricted |
| Date published | 2008-07-28 |
| Advisor (committee chair) | Periana, Roy A. |
| Advisor (committee member) |
Prakash, G. K. Surya Williams, Travis J. Petruska, John A. |
| Abstract | The first chapter is an introduction to the development of carbon-hydrogen bond, (C-H), activation. The use of acidic solvents for C-H activation is addressed, and catalyst inhibition by water or methanol is discussed as one of the major problems in creating active catalysts. New approaches for designing C-H activation/functionalization catalysts that operate in water are discussed.; Chapter two is the study of an electron rich platinum complex, Pt(NNC)TFA where NNC = 6-phenyl-4,4'-di-tert-butyl-2,2'-bipyridine and TFA = trifluoroacetate, designed to overcome the water inhibition of the Pt(bipyrimidine)Cl2 catalyst. The mechanism for the H/D exchange between benzene and trifluoroacetic acid is studied using this catalyst. The energetics for C-H activation (both coordination and cleavage of the C-H bond) by the Pt(bipyrimidine)(TFA)2 complex and the Pt(NNC)TFA complex are calculated and compared by DFT.; Chapter three is the synthesis and reactivity of a water soluble cyclometallated (NNC)Ir(OH)2Py complex that is competent for the H/D exchange of benzene and water. This complex was insoluble in water at elevated temperatures (150 degrees C), which hindered its use as a catalyst. To overcome the insolubility in water at elevated temperatures, I designed water soluble (NNC derivatives) ligands. Several of these water soluble iridium complexes were synthesized and tested. Further work is ongoing in this area to determine if there is a pH dependence on rate of C-H activation using these catalysts.; Chapter 4 is a collection of related work. The first section is the synthesis of a water soluble cyclometallated bisphenylpyridine iridium mu-OH bridged dinuclear complex. This complex is being synthesized for the C-H activation of hydrocarbons in basic aqueous media and to gain further understanding about mu-hydroxo bridged dinuclear complexes. The second section contains DFT calculations of an iridium(I) bipyridine hydroxo aquo complex for the C-H activation of hydrocarbons in water. Protonation of the electron rich iridium(I) center by water is found to be highly exothermic, which results in a ground state stabilization. Calculations were also performed on Goldberg's cyclometallated (PNP) iridium hydroxo complex, and the protonation by water is calculated to be endothermic. Lastly, a sterically hindered NNC ligand is synthesized. Attempts have been made to cyclometallate it to iridium for the purpose of generating a five coordinate complex that could show interesting chemistry. |
| Keyword | hydroxo; C-H activation; iridium |
| 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-m1427 |
| Rights | Meier, Steven Karl |
| 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-Meier-20080728 |
| Archival file | uscthesesreloadpub_Volume40/etd-Meier-20080728.pdf |
Description
| Title | Page 1 |
| Full text | CATALYTIC C-H ACTIVATION BY CYCLOMETALLATED IRIDIUM HYDROXO COMPLEXES IN AQUEOUS MEDIA by Steven Karl Meier A Dissertation Presented to FACULTY OF THE GRADUATE SCHOOL UNIVERSITY OF SOUTHERN CALIFORNIA In Partial Fulfillment of the Requirements for the Degree DOCTOR OF PHILOSOPHY (CHEMISTRY) August 2008 Copyright 2008 Steven Karl Meier |
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