Cooperative Institute for Research in Environmental Sciences at the University of Colorado Boulder

Atmospheric Chemistry Program Seminar

Iron polypyridyl complexes for electrocatalytic proton reduction

Zachary Schiffman, ANYL 1st year student

"In recent decades the rate of human consumption has accelerated dangerously. This is especially true of energy, the usage of which is unsustainable for long-term continuation at the current rate. We should then turn to renewable energy using materials that can be used infinitely, as opposed to fossil fuels which are notably finite and are contributing to the continuously rising levels of greenhouse gas pollution.

Solar energy would be a source of clean energy. An idea for a method of harnessing and storing solar energy is inspired by Earth’s plant life. In the process of photosynthesis, plants take in sunlight and store the solar energy in the form of chemical bonds. Just as plants reduce carbon dioxide to produce sugars as fuel, we look to use the energy of the sun to reduce protons from water into hydrogen gas, which burns cleanly with no CO2 emission. Metal-based complexes have been developed which can act as catalysts for this hydrogen evolution reaction (HER). Many of these complexes are synthesized in lengthy, low-yielding processes. In terms of developing practical technology that can be used on a large scale, it is best to synthesize these complexes in a straightforward, easy synthesis using inexpensive, commercially available materials.

We produced a tridentate bismethylpyridyl amine bound to an iron (III) center. This complex is synthesized from commercially available materials in high yield, and was shown to be an active electrocatalyst for proton reduction. Cyclic voltammetric techniques were used to verify and benchmark the complex’s activity and efficiency as an electrocatalyst. It was also shown to be active as a pre-catalyst in a three-component system for photocatalytic hydrogen generation. To this end, we seek to simplify our catalyst precursors to produce a readily synthesized complex that can be obtained at low cost and in high yields. This may take us one step closer to developing a wide-spread, accessible system for artificial photosynthesis."


Synthesis of Phosphate Diesters for use as Ligands on Bismuth Catalysts

Bri Dobson, ANYL 1st year

"New catalysts can simplify synthetic schemes or open up new possibilities in synthetic chemistry. In particular, bismuth phosphates have shown promise as an expanding family of green catalysts. Some bismuth compounds have Lewis acid catalyst properties but need to be made more effective in order to be used industrially. Phosphate diesters with varying ester groups may be able to tune the activity of these catalysts to fit specific reactions. With the final goal of creating a tunable bismuth phosphate diester catalyst, this project attempted to find a simple, but effective method for synthesizing a variety of phosphate diesters, which could then be used as ligands on homogenous bismuth phosphate diester Lewis acid catalysts for a variety of different synthetic uses. Two schemes for phosphate diester synthesis were attempted. One of the two was successful in the synthesis of pentamethylene phosphate. Further testing with different reagents is needed to establish the applicability of this scheme to the synthesis of other phosphate diesters, but the preliminary results are promising."

Please note: seminar starts at 12:40 PM. Contact for Zoom link.


Monday, November 2, 2020

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