Probing Speciation and Structure of Cd(II), Hg(II) and Pb(II) with Multidentate Chelating Ligands

College Of William And Mary, Williamsburg VA

Investigators

Abstract

Dr. Deborah Bebout, Chemistry Department, College of William and Mary, is supported by the Inorganic, Bioinorganic, and Organometallic Program of the Chemistry Division for research into the chemistry of Cd(II), Hg(II) and Pb(II) with multidentate chelating ligands. The speciation of Cd(II), Hg(II), and Pb(II) complexes that model thermodynamically stable heavy metal coordination environments in physiological environments will be investigated in solution by NMR. Conditions for slow exchange on the chemical shift and coupling constant time scales will be investigated with each metal-ligand pair. X-ray structures and solid state NMR properties of selected complexes will be determined. The solution- and solid-state NMR parameters will be correlated with structural features for the development of structure-function relationships that can be used to describe the behavior of these metal ions in biological systems. In spite of intense study, the molecular mechanisms underlying the biological behavior of heavy metal ions are still largely unknown. Since heavy metals are toxic, persistent, and accumulate in ecosystems, an understanding of relevant heavy metal binding motifs is of fundamental importance. Unfortunately, in natural systems heavy metals have affinity for numerous binding agents. This study will systematize the behavior of cadmium, mercury, and lead in systems that mimic those found in nature. The results will provide basic information that will aid in the understanding of how these metal ions react in the environment and in living systems. The project will involve undergraduates and masters level students. A number of these will be women.