A5021263125- X-ray Diffraction in Crystallography
- Crystallization and Solubility Studies
- Crystallography and molecular interactions
- Radioactive element chemistry and processing
- CO2 Reduction Techniques and Catalysts
- Advancements in Battery Materials
- Lanthanide and Transition Metal Complexes
- Electrocatalysts for Energy Conversion
- Advanced Photocatalysis Techniques
- Electrochemical Analysis and Applications
- Molten salt chemistry and electrochemical processes
- TiO2 Photocatalysis and Solar Cells
- Coordination Chemistry and Organometallics
- Molecular Junctions and Nanostructures
- Advanced battery technologies research
- Iron oxide chemistry and applications
- Advanced Battery Materials and Technologies
- Analytical Chemistry and Sensors
- Radioactive contamination and transfer
- Ammonia Synthesis and Nitrogen Reduction
- Metal complexes synthesis and properties
- Chemical Synthesis and Characterization
- Metalloenzymes and iron-sulfur proteins
- Semiconductor materials and devices
- Copper-based nanomaterials and applications
Los Alamos National Laboratory
2011-2025
Grinnell College
2023
University of Michigan
2016-2022
Synthetic routes to salts containing uranium bis-imido tetrahalide anions [U(NR)(2)X(4)](2-) (X = Cl(-), Br(-)) and non-coordinating NEt(4)(+) PPh(4)(+) countercations are reported. In general, these compounds can be prepared from U(NR)(2)I(2)(THF)(x) (x 2 R (t)Bu, Ph; x 3 Me) upon addition of excess halide. providing stable coordination complexes with the [U(NMe)(2)](2+) cation also reacts Br(-) form [NEt(4)](2)[U(NMe)(2)Br(4)] complexes. These materials were used as a platform compare...
Cyclic voltammetry, UV-vis, and X-ray absorption spectroscopy were used to demonstrate that aqueous plutonium coordination chemistry electron transfer reactivity can be controlled by judicious manipulation of hydrochloric acid concentrations.
A series of cobalt bis(benzenedithiolate) complexes with varying benzenedithiolate (general abbreviation: bdt2-) ring substitutions (S2C6X42-) were prepared and adsorbed on inexpensive electrodes composed (a) reduced graphene oxide (RGO) electrodeposited fluorine-doped tin (FTO) (b) highly ordered pyrolytic graphite (HOPG). The catalyst-adsorbed are characterized by X-ray photoelectron spectroscopy. Catalyst loading across the ligand improved notably increasing halide substitution [from 2.7...
Synthetic routes to alkyl and aryl substituted dithiophosphinate salts that contain non-coordinating PPh(4)(+) counter cations are reported. In general, these compounds can be prepared via a multi-step procedure starts with reacting secondary phosphines, i.e. HPR(2), two equivalents of elemental S. The synthetic transformation proceeds by oxidation the phosphine followed insertion S into H-P bond. This approach was used synthesize series dithiophosphinic acids were fully characterized,...
Reduced graphene oxide (RGO) films have been prepared by immersion of (GO) at room temperature in nonaqueous solutions containing simple, outer-sphere metallocene reductants. Specifically, cobaltocene, cobaltocene and trifluoroacetic acid (TFA), decamethylcobaltocene each showed activity for the rapid reduction GO cast on a wide variety substrates. Each reactant increased conductivity several orders magnitude, with RGO either or TFA possessing highest conductivities (∼104 S m-1). X-ray...
Heterogeneous dihydrogen production manifolds comprised of bulk graphite, pencil graphite powder in Nafion films, graphene, and glassy carbon electrodes with adsorbed proton reduction catalyst TBA[Co(S2C6Cl2H2)2] have been prepared tested for their efficiency to generate acidic aqueous media. The on these inexpensive graphitic surfaces consistently displays similar electrocatalytic profiles compared the same highly ordered pyrolytic (HOPG) supports, including high activity moderately...
Catalytic MoSx thin films have been directly photoelectrodeposited on GaInP2 photocathodes for stable photoelectrochemical hydrogen generation. Specifically, the deposition conditions were controlled to obtain 8–10 nm p-GaInP2 substrates without ancillary protective layers. The nominally composed of MoS2, with additional MoOxSy and MoO3 species detected showed no long-range crystalline order. as-deposited material excellent catalytic activity toward evolution reaction relative bare p-GaInP2....
Herein, we have evaluated relative changes in M–S electronic structure and orbital mixing Group 6 MS42− dianions using solid- solution-phase S K-edge X-ray absorption spectroscopy (XAS; M = Mo, W), as well density functional theory (DFT; Cr, W) time-dependent (TDDFT) calculations. To facilitate comparison with solution measurements (conducted acetonitrile), theoretical models included gas-phase calculations those that incorporated an acetonitrile dielectric, the latter of which provided...
Controlling structure and reactivity by manipulating the outer-coordination sphere around a given reagent represents longstanding challenge in chemistry. Despite advances toward solving this problem, it remains difficult to experimentally interrogate characterize impact. This work describes an alternative approach that quantifies effects. It shows how molten salt metal chlorides (MCln; M = K, Na, n 1; Ca, 2) provided excellent platforms for characterizing influence of cations (Mn+) on redox...
Plutonium-based technologies would benefit if chemical hazards for purifying plutonium were reduced. One critical processing step where improvements could be impactful is the adjustment of oxidation-states during separations. This transformation often requires addition redox agents. Unfortunately, many agents used previously cannot today because their properties are deemed incompatible with modern day facilities and waste stream safety requirements. We demonstrated herein that photochemistry...
The preparation and identification of an unusually stable viologen radical has been demonstrated. intramolecular interactions bis-viologen species such as 1,1"-[1,2-phenylenebis(methylene)]bis[1'-methyl-4,4'-bipyridinium] (1) 1,1"-(1,3-propanediyl)bis[1'-methyl-4,4'-bipyridinium] (2) upon reduction complexation by cucurbit[8]uril (CB[8]) result in the formation a unique monoradical species. Cyclic voltammetric responses for 1 2 presence CB[8] showed splitting degenerate e− redox wave...
p-Type gallium phosphide (GaP) electrodes have been sensitized by triarylmethane dyes physisorbed from aqueous solutions. This work is the first to show light-stimulated hole injection an adsorbed molecular chromophore on native GaP surfaces. Freshly etched p-GaP(100) and p-GaP(111)A were loaded with dye brief soaking in solutions of Fast Green. X-ray photoelectron spectroscopy, corroborated Auger electron indicated that such treatments yield undetectable surface coverages. However,...
Recent advances enabled the discovery of heterometallic molecules for many metals: main group, d-block, lanthanides, and some actinides (U, Th).
A series of four lanthanide thenoyltrifluoroacetone (TTA) complexes consisting two f0 (La3+ and Ce4+) f1 (Ce3+) was examined using steady-state time-resolved spectroscopic techniques. The wide range techniques presented herein have enabled us to discern the nature excited states (charge transfer, CT vs ligand localized, LL) as well construct a Jablonski diagram for detailing state reactivity within molecules. wavelength excitation power dependence these are first direct verification presence...
The local structure of the liquid metal/electrolyte interface for Hg electrodes immersed in aqueous solutions suitable crystalline Ge electrodeposition was probed by situ X-ray reflectivity. A series reflectivity measurements were collected both pure 0.1 M Na2B4O7 solution and with 0.05 GeO2 at potentials where there are no faradaic redox reactions. Quantitative analysis these data indicates that is indistinguishable from NaF solution, suggesting nonspecific adsorption borate ions. In...