University of Missouri - Saint Louis

The Graduate School


An oral examination in defense of the dissertation for the degree

Doctor of Philosophy in Chemistry

Surendra Dawadi
M.S. in Chemistry, May 2010, University of Missouri - St. Louis
M.Sc. in Chemistry, September 2005, Tribhuvan University, Kathmandu, Nepal

Design and synthesis of chelating compounds and solid-supported chelators for metal depleted solutions



Metals are essential to life, yet they can be toxic (or even fatal) for biological systems when present in excessive amounts. The major source of metal overload in humans is diet; in some cases, intravenous feeding. Thus the removal of toxic metal ions from contaminated clinical products such as total parenteral nutrition (TPN) solutions and drinking, and waste waters is extremely important. The use of chelating resin, which is a polymeric solid containing covalently immobilized chelating compound, for the selective removal of metal ions from contaminated solutions has been proposed.

Overall, this dissertation embodies the design, synthesis, and metal binding studies of novel chelators and chelating resins and the application of these resins for the selective removal of metal ions from contaminated solutions. Solution phase hydroxamate chelators have been synthesized for the selective binding of trivalent metals such as iron and aluminum in the presence of divalent metals such as calcium. These chelators have potential applications as chelating agents in the treatment of iron and aluminum overload. A set of strongly binding chelators have been immobilized on solid support via various linkages. These solid supported chelators have been employed to selectively remove aluminum from contaminated TPN components such as calcium gluconate solution. One of the optimized resins has removed more than 90% of aluminum from commercial calcium gluconate solutions. This technology, of employing hydroxamate functionalized resin for the removal of aluminum from calcium gluconate solution, will be available in hospitals soon and will greatly benefit premature neonates and patients in critical condition receiving TPN solution for life support. Additionally, citramide functionalized chelating resins have been prepared for the removal of trivalent metals from contaminated solutions at low pH, and dithiolate based chelating resins were prepared for the removal of high priority toxic metals such as lead, mercury, cadmium, and arsenic from aqueous solutions.


Date: June 14, 2013

Time: 10:00 a.m. to noon

Place: 451 Benton Hall


Defense of Dissertation Committee


Prof. Christopher D. Spilling, Ph.D. (Advisor)

Prof. Wesley R. Harris, Ph.D.


Prof. Alexei V. Demchenko, Ph.D.

Prof. James J. O’Brien, Ph.D.