Category Archives: inorganic chemistry

Thy Nguyen–Donor-Acceptor Characterization of Homoleptic Cobalt Dithione Complexes

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Abstract: “Metallodithiolene complexes are well known for their charge transfer properties that great promise towards the development of material science due to the non-innocent nature of the dithiolene ligand. Dithione (Dt0) ligands exhibit significant charge delocalization across their thioamide moiety, making them redox-active ligands. The ability for Dt0 ligands to participate in redox processes, in conjunction with transition metalcore, grants such complexes potential access to additional redox states. In this project, octahedral cobalt Dt0 complexes, [Co(Me2 Dt0)3][PF6]3 (1) and [Co(iPr2 Dt0)3][PF6]3, (2) have been thoroughly characterized utilizing elemental analysis, mass spectroscopy, IR, UV-Vis, NMR, cyclic voltammetry, and DFT calculations. The excited state transitions of 1 and 2 were determined with TD-DFT calculations and visualized using electronic density difference maps (EDDMs). Low energy charge transfers for 1 and 2 are determined to be MLCT, while higher energy transitions are assigned as Dt0-based p → p* LL’CT.”

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Kylie Smith–Inorganic Chemistry Lab Development: Iron Solubility

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Abstract: “The electronic configuration and chemistry of iron allows for a variety of coordination compounds and complexes to be formed. These complexes consist of the metal ion bound to ligands, which can be nonmetal ions, small molecules such as H2O, NH3, or large molecules including organic ligands. Metal complexes are important to the function of proteins. For example, heme is a coordination complex of an iron ion coordinated to a porphyrin. Heme is a precursor to hemoglobin which can bind oxygen in the blood. Another example is nitrogenase, an enzyme in cyanobacteria that is important in nitrogen fixation. We are developing an inorganic chemistry lab experiment that introduces students to the coordination chemistry of iron by allowing them to relate complex formation to color changes and solubility. The objectives of the experiments presented here are: i) Observe and understand the chemistry of transition metal complexes. ii) Correctly calculate and prepare solutions of known concentrations. iii) Determine and explain changes in color and solubility in terms of metal-ligand interactions. iv) Analyze metal-ligand formation and generate evidence-supported conclusions. Students explore several concepts related to transition metal chemistry, coordination chemistry, oxidation-reduction reactions, and solubility.”

 

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Vennela Mannava–Carbon Dioxide Utilization in Plastic Production: Development of a Nickel Catalyst

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Abstract: “Carbon dioxide emissions, known to exacerbate climate change, have been increasing rapidly over the past century. One strategy to alleviate this issue is carbon capture and utilization (CCU), in which atmospheric CO2 is used to produce more valuable compounds. An attractive target is sodium acrylate, the building block of superabsorbent polymers found in many common goods. Researchers have sought a reaction coupling CO2 and ethylene, which would produce acrylate from sustainable starting materials. Nickel catalysts have been able to facilitate this coupling but suffer from low efficiency, due to the formation of a nickelalactone intermediate. This has a very stable ring structure that resists the release of acrylate from the catalyst. My project aims to develop supporting ligands for the catalyst that provide appropriate steric bulk and electron density to the nickel center to promote efficient nickelalactone ring-opening. Current work focuses on N-heterocyclic carbene (NHC) ligands, which are very electron-donating and highly modular. Preliminary experiments on a simple bis(NHC) nickelalactone and computational investigation of other ligand systems with varying properties predicts that strong electronic asymmetry and broad steric bulk are vital to ligand design for destabilizing nickelalactones. These NHC ligands could be the key to efficient nickel catalysts coupling CO2 and ethylene for sodium acrylate production, thus contributing to global CCU efforts.”

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Allyson Imfeld–Inorganic Chemistry Experiment: Formation and Properties of Copper Coordination Complexes

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Abstract: “Metal ions usually exist in the form of coordination complexes. The properties of such complexes include different colors, photo-physical characteristics, magnetics, reactivity, biological activity, and catalytic properties.(1) The biological activity of metal-ligand interactions has found many pharmaceutical, clinical and other practical applications. The experiments being presented here are part of a series of inorganic chemistry lab experiments designed to examine the solubility of metal ions and their ability to form coordination complexes. This particular lab focuses on the complex formations of copper by performing a series of color changing reactions. Four primary objectives include: i) Improve hands-on skills in how to prepare chemical solutions of specific molarities. ii) Understand how to prepare a series of Cu metal complexes in solution. iii) Observe color changes and precipitation reactions associated with complex formations, and iiii) analyze results in regards to metal-ligand formation. This lab experiment provides students with a multi-faceted look at different chemical principles including formation of coordination complexes, solubility, redox chemistry and the chemistry of transition metals.

New Laboratory Module, Why Metals and Ligands Like Each Other, Purdue, Inorganic Chemistry Laboratory, CHM342, Experiment developed in 2020.

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Cade Meiss–Ruthenium based therapeutics for Alzheimer’s research

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Abstract: “Alzheimer’s disease is a neurodegenerative disease currently found in some of our aging population. One key feature of the disease is the observation of deposits of the small peptide Amyloid-Beta (Aβ). The goal of using ruthenium-based (Ru) compounds is to prevent the aggregation of Aβ, thereby decreasing the formation of Aβ plaques. Two Ru compounds were synthesized using quinoline derivatives. The compounds were then studied by a Thioflavin T assay and Dynamic light scattering. Both compounds were also characterized by NMR and ESI-MS spectroscopy and found to be consistent with literature values. Next, the complexes were evaluated for their ability to inhibit the aggregation of the Aβ peptide, with C2 showing a strong inhibition of the peptide. The compounds have been found to inhibit the Aβ aggregation, but there has yet to be a cytotoxicity screening toward glial cells to ensure the compounds are not cytotoxic. Both compounds have promise, but there are more tests necessary to determine their actual benefit.”

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