Design, Synthesis, and Characterization of a Lanthanide Ion Coordination Complex for Arsenic Detection

Indianapolis, IN

Arsenic (As) contamination of groundwater, a naturally-occurring form of pollution in deep levels of groundwater, is currently a high-profile global problem. Drinking water sources in certain regions of heavily affected countries such as Bangladesh, Chile, Argentina, and India still contain toxic levels of arsenic, at concentrations multiple times higher than that in the World Health Organization (WHO) guidelines for drinking water quality. Current means of arsenic detection are either expensive, not sensitive enough, or require toxic reagents or complex instrumentation. We seek to develop a sensitive, reliable, and affordable method of detecting arsenic in an aqueous environment. Small molecule sensors, with their abilities to detect metal ions, may be able to satisfy all these criteria. The luminescent properties of the trivalent lanthanide ions (Ln(III)) are conducive to the development of such a sensor. In addition, Ln(III) ion complexes eliminate common weaknesses of current small molecule sensors, namely short lifetimes and inconsistent sensitivities. A novel pybox ligand, Pybox(thioether), has successfully been synthesized and characterized. Eu(III) and Tb(III) complexes of this ligand has been prepared and preliminary metal sensing studies demonstrated its ability to detect arsenic at the μM level. These studies suggest the complexes’ viability as small molecule sensors for arsenic detection.