Date of Award
12-2020
Document Type
Open Access Thesis
Degree Name
Master of Science (MS)
Department
Chemistry
First Advisor
Jonathan Rochford
Second Advisor
Jason Evans
Third Advisor
Michelle Foster
Abstract
The catalytic proton-coupled reduction of carbon dioxide into C-1 or “common engine” liquid fuels is currently a highly desirable and green approach to removing anthropogenic CO2 from the atmosphere. The most common approach to this is through electrocatalytic homogeneous reductions utilizing inorganic complexes as catalysts. Current research has moved towards the use of first-row transition metals in catalysts due to their high natural abundances and cheap cost. Iron porphyrin complexes have been vastly studied due to their high product selectivity and turnover frequencies. However, these complexes exhibit short lived activity because of competing reactions in their catalytic cycles, rendering them inactive. This project seeks to improve on existing iron CO2 reduction catalysts by constructing them with novel tridentate N-heterocyclic carbene ligands. The possibility exists that the strongly σ-donating and π-accepting character of the NHC functional group will drastically lower the thermodynamic barrier associated with carbon CO dissociation via the trans-effect, enhancing the number of catalytic turnovers capable under electrochemical conditions for Fe-based catalysts. A class of these catalysts will be synthesized and studied extensively through infrared spectroscopy, UV-vis spectroscopy, electrochemistry and electrocatalysis to test this hypothesis and attempt to tune it to maximize catalytic efficiency.
The development of transition metal complexes with a strong visible to near infrared (visNIR) absorption has been a long-term goal among inorganic chemists for their potential applications as photosensitizers and medical imaging contrast agents. The electronic and photophysical properties for a series of ruthenium(II) photosensitizers is here presented where a series of five π-accepting ligands based upon a 5-(vinyl-cyanine)-8-oxyquinolate scaffold have been investigated. A combination of computational, UV-Vis-NIR absorption, phosphorescence emission and cyclic voltammetry studies are used to assess the influence of these ligands on complex electronic and photophysical properties and to assess their potential as vis-NIR photoacoustic contrast agents.
Recommended Citation
Catsoulis, Peter Andrew, "Selective Electrocatalytic Reduction of Co2 To CO with Iron Nheterocyclic Carbene Complexes and Near-Infrared Absorbance of Ruthenium(II) Photosensitizers Containing a Merocyanine π-Acceptor" (2020). Graduate Masters Theses. 665.
https://scholarworks.umb.edu/masters_theses/665