Dissertation Defenses

Doctoral Dissertation Announcement

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Candidate: Venkat Reddy Guduru

Degree of: Doctor of Philosophy

Department: Chemistry

Title: Synthesis, Study of Self-assembly, and Trivalent Lanthanide Metal Ions Recognition Characteristics of Amphiphilic Acylpyrazolone and Amphiphilic Acylisoxazolanes

Committee:
Dr. Ekkhard Sinn, Chair
Dr. Subra Muralidharan
Dr. Sherine O’Bare
Dr. Yirong Mo
Dr. Muralidhar K. Ghantasala

Date: Thursday, November 8, 2007 4:30 p.m. – 6:30 p.m.
1260 Wood Hall

Abstract:
This research project focused on the separation of trivalent lanthanide metal ions by HPLC using amphiphilic acylpyrazolones and acylisoxazolones. The central hypothesis of this dissertation is that the nanoscale self-assembly nature of amphiphilic ligands (chelating lingads) can influence their metal ion recognition and separation. To test the central hypothesis, we have synthesized a family of novel amphiphilic ligands and employed them as model systems for the separation of trivalent lanthanide metal ions. Several novel intermediates such as 4-acylated, N-acylated, O-acylated pyrazolones and isoxazolones, have been efficiently synthesized and fully characterized.

The trivalent lanthanide metal ion recognition efficacies of these amphiphilic ligands have been demonstrated through baseline separations of a mixture of light, middle, and heavy lanthanide ions by employing them in the aqueous mobile phase of high performance liquid chromatography (HPLC) with C18 silica gel as the stationary phase. The complex separation mechanism is influenced by the chemical structure of 4-acylated amphiphilic ligands and their spontaneous self-assembly in the aqueous phase, as well as on the stationary phase. Transmission electron microscopy (TEM) images of these (over) amphiphilic ligands in the aqueous phase in the absence and presence of metal ions demonstrated several nanoscale structures such as spherical, dendritic, and linear (nano-rods, nano-tubes, nano-fibers) structures.