One of the most challenging and pressing issues confronting our nation is the safe and cost-effective management of environmental pollutants and the remediation of hazardous waste sites. To capture aqueous hazardous waste, porous metal-oxides/hydroxides and silicates with diverse compositions, structures, and macroscopic morphologies have been used for decades. However, most metal-oxide materials are so structurally complex that reactions that take place at the solid-surface interface are not well understood. In order to enhance adsorption and exchange properties of metal-oxide materials, a molecular-level understanding of how the solid oxide surface reacts is critical.

Our research efforts focus on aqueous transition-metal chemistry of metal-oxo clusters. We establish fundamental relationships between structure and reactivity for metal-oxide materials by employing the use of aqueous Nb, Mo, W, and Rh-oxo model compounds (See Figure 1). We synthesize our transition metal clusters using traditional inorganic synthetic techniques and characterize our compounds using NMR (1H, 17O, 103Rh, 95Mo), electronic spectroscopy and infrared spectroscopy. Once synthesized, we measure rates of ligand substitution at the metal clusters using variable-temperature NMR spectroscopy. Understanding rates of substitution are particularly important since these reactions are similar to those that take place at metal-oxide remediation materials.