RUI:CAS:Reaction Dynamics of Anderson-Type Polyoxometalate Ions in Aqueous Solution: Relating Solid-State Structures with Solution-State Properties

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WIth support from the Chemical Structure, Dynamics & Mechanisms-B (CSDM-B) Program of the Chemistry Division and the Established Program to Stimulate Competitive Research (EPSCoR), Eric Villa of the Department of Chemistry and Biochemistry at Creighton University is focused on determining how the structural features of simple polyoxometalate ions (predominately-anionic metal-oxide clusters) affect their reactivity in aqueous solution. The range of applications for these polyoxometalate (POM) ions is wide, with properties including antiviral/antitumor activity, acid catalysis, water oxidation catalysis, MRI contrast agents, luminescent and magnetic materials, and potentially radioactive waste treatment. The goal of this research is to understand how POMs react in aqueous solution and what controls their reactivity in solution. The resulting data from this project will allow for POMs to be better tuned for these important applications. This project engages undergraduate students in fundamental research and gains them training in inorganic chemistry, which includes several analytical techniques and instrumental methods. Undergraduate students will also be involved in the set-up and delivery of a middle school chemistry summer camp focusing on inorganic chemistry. This project focuses on understanding the stability and reactivity of Anderson-type POM ions (XMo6O24z-) in aqueous solution. Here, the primary goal is to pinpoint how changes in the identity of atom X alters the ion’s properties in aqueous solution to be able to correlate structure-property relationships. The Anderson-type POM has only three types of structural oxygen, making it an ideal structure for undergraduate researchers to appreciate the complexities of aqueous solution reactivity. Importantly, the general reactivity trends of POMs in aqueous media have not been clearly identified and still have many unanswered questions: 1) What types of oxygen sites exchange the fastest? 2) What affects only a single site versus what affects the entire unit? 3) What structural properties (bond lengths, charge state or protonation) correlate with reactivity? 4) How general are the trends observed? 5) Critically, can the reactivity of POMs in water be easily predicted? 6) Finally, how do single, targeted metal substitutions affect the ability of the POM to make stable complexes with surrogates of radioactive cations for remediation purposes? The small Anderson-type POMs will allow undergraduate researchers to confidently probe the above questions and the data collected will allow for the ability to better tune these ions to their impressive set of applications.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.