Chemistry Commons^™

Phenolate Derivatives Of Octanuclear Iron-Oxo-Pyrazolato Complexes; Enantiomeric Resolution Of T-Symmetry Species, Konstantinos Lazarou

FIU Electronic Theses and Dissertations

Octanuclear ferric complexes involving achiral phenolates of the general formula [Fe₈(μ-O)₄(μ-pz)₁₂(R-C₆H₄O)₄], (R = 4-NO₂, 4-CN, 4-F, 4-Cl, 4-I, 4-CH₃O, and 3-NO₃), where synthesized and characterized by single crystal X-ray crystallography, elemental analysis, ¹H-NMR, UV-Vis, IR, ⁵⁷Fe Mössbauer spectroscopy and electrochemical methods (cyclic and differential pulse voltammetry). Results indicate that the nature of the phenolate substituents allows the fine tuning of the spectroscopic data of the compounds.

Subsequently, this project focused on the resolution of the racemic …

Mapping Of The Chromium And Iron Pyrazolate Landscape, Jessica Maria Lopez

FIU Electronic Theses and Dissertations

The main objective of this project is to synthesize the first family of polynuclear chromium pyrazolate complexes. Complexity in analysis of the experimental magnetic data of multinuclear complexes arises from their (2S +1)^N microstates, where S is the spin of each metal center and N is the number of metal centers. For example, high-spin (HS)-Fe^III₃ has 216 microstates and HS-Fe^III₈ ≈ 1.7x10⁶ microstates (S= 5/2). However, complexes with chromium(III) S = 3/2 will have a noticeable reduction of microstates. Mononuclear complexes with formula [mer-CrCl₃(pzH*)₃] (pz*H = pyrazole, 3-Me-pzH, …

Electrochemical Characterization Of Self-Assembled Monolayers On Gold Substrates Derived From Thermal Decomposition Of Monolayer-Protected Cluster Films, Michael C. Leopold, Tran T. Doan, Melissa J. Mullaney, Andrew F. Loftus, Christopher M. Kidd

Chemistry Faculty Publications

Networked films of monolayer-protected clusters (MPCs), alkanethiolate-stabilized gold nanoparticles, can be thermally decomposed to form stable gold on glass substrates that are subsequently modified with self-assembled monolayers (SAMs) for use as modified electrodes. Electrochemical assessment of these SAM-modified gold substrates, including double-layer capacitance measurements, linear sweep desorption of the alkanethiolates, and diffusional redox probing, all show that SAMs formed on gold supports formed from thermolysis of MPC films possess substantially higher defect density compared to SAMs formed on traditional evaporated gold. The density of defects in the SAMs on thermolyzed gold is directly related to the strategies used to assemble …

Enhanced Electrochemistry Of Nanoparticle-Embedded Polyelectrolyte Films: Interfacial Electronic Coupling And Distance Dependence, Callie E. Dowdy, Michael C. Leopold

Chemistry Faculty Publications

Factors affecting the electronic communication believed to be responsible for the enhanced solution electrochemistry observed at electrodes modified with hybrid polyelectrolyte–nanoparticle (PE–NP) film assemblies were systematically investigated. Specifically, the faradaic current and voltammetric peak splitting recorded for cyclic voltammetry of ferricyanide redox species (Fe(CN)63−/4−) at films constructed with various architectures of citrate-stabilized gold NPs embedded in polyelectrolyte films composed of poly-l-lysine and poly-S-styrene were used to establish the relative importance of both distance and electronic coupling. Layer-by-layer construction of PE–NP films allowed for the position and density of NPs to be varied within the film to assess electronic coupling between …

Monolayer-Protected Nanoparticle Film Assemblies As Platforms For Controlling Interfacial And Adsorption Properties In Protein Monolayer Electrochemistry, Andrew F. Loftus, Katelyn P. Reighard, Susanna A. Kapourales, Michael C. Leopold

Chemistry Faculty Publications

Assembled films of nonaqueous nanoparticles, known as monolayer-protected clusters (MPCs), are investigated as adsorption platforms in protein monolayer electrochemistry (PME), a strategy for studying the electron transfer (ET) of redox proteins. Modified electrodes featuring MPC films assembled with various linking methods, including both electrostatic and covalent mechanisms, are employed to immobilize cytochrome c (cyt c) for electrochemical analysis. The background signal (non-Faradaic current) of these systems is directly related to the structure and composition of the MPC films, including nanoparticle core size, protecting ligand properties, as well as the linking mechanism utilized during assembly. Dithiol-linked films of Au225(C6)75 are …