Metal-based Electron Transfer Processes under Confinement: A Kinetic and Spectroscopic Study of Modified Reactivity in Oil-water RM Microemulsions

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The Chemical Structure, Dynamics and Mechanisms Program supports Professor Michael D. Johnson of New Mexico State University to investigate and characterize the location of redox active metal complexes in reverse micelles (RMs) using a combination of NMR, UV-vis and FTIR techniques. The goal is to better understand complex reactivity as a function of compartmentalization via interfacial penetration, and to investigate catalysis via increased ion pairing at the interface. Microelectrode electrochemistry will be used to establish whether modified reactivity in RMs is due to a change in the Marcus driving force. Professor Johnson will also measure the rates of electron transfer for a set of complexes with systematic variation in complex charge (local electrostatics at the interface), location, hydrophobicity and ligand nucleophilicity. The aim is to correlate reactant location with thermodynamic parameters such as redox potentials. The work has potentially broad biological impact in the refining of metallodrug uptake efficiency and assimilation when redox chemistry precedes the onset of physiological activity, e.g., in anti-cancer agents (PtIV/II, RuIII/II) and vanadium agents for diabetes (VV/IV). The results may also help predict the rates of redox reactions in vivo within small molecule siderophores (FeIII/II). Non-biological applications include predictions of aqueous chemical reactivity within the cavities of catalytic microporous solids, and within the water droplets formed during electrospray MS, which have been assumed (but not verified) to be representative of the chemistry in bulk solution.Professor Johnson has extensive experience in student training and outreach and is especially committed to undergraduate research involving underrepresented groups, particularly Hispanic and Native American students. He is directly involved in a Minority Access to Research Careers program at NMSU - one of the largest MARC programs in the country, sending 8-10 graduating senior students per year to graduate programs in the physical and life sciences. Other students have gone on for MD, DDS, DPharm., D.Psy. or other post graduate degrees. Through this program Professor Johnson has impacted over 200 undergraduates during the past 15 years. Professor Johnson also participates in the Bridges programs at NMSU, whose mission is to increase the transfer rate of Native American Students in Arizona and New Mexico from area community colleges to 4-year degree programs. He is also active in the annual Undergraduate Research and Creative Arts Symposium (URCAS) at NMSU.