Synthesis of nontraditional tetrapyrrole ligand platform for small molecule activation
| Author(s) | Cai, Qiuqi | |
| Date Accessioned | 2021-03-31T16:21:13Z | |
| Date Available | 2021-03-31T16:21:13Z | |
| Publication Date | 2020 | |
| SWORD Update | 2021-02-08T17:04:15Z | |
| Abstract | Two families of nontraditional tetrapyrrole scaffold, biladiene and isocorrole, which contain one sp3 hybridized carbon at different meso-positions, were synthesized. The two series of freebases were characterized by NMR spectrometry, UV-vis spectra and X-ray diffraction experiment. Their metal complexes, cobalt and palladium derivatives, were also synthesized to investigate their applications for electrocatalytic oxygen reduction reaction, carbon monoxide activation and photodynamic therapy. ☐ Both cobalt 5-isocorrole and cobalt 10-isocorrole derivatives, which have sp3 hybridized carbon on the 5 or 10 position, performed extraordinary selectivity for dioxygen reduction, compared with literature reported cobalt tetrapentafluorophenylporphyrin and cobalt tripentafluorophenylcorrole. The oxygen reduction has two main product which is 2e–, 2H+ pathway to produce hydrogen peroxide and 4e–, 4H+ pathway to produce water. Each pathway has potential applications for fuel cells and energy storage. The two series of cobalt isocorrole complexes were characterized by cyclic voltammetry, UV-vis absorption and X-ray diffraction experiments. They displayed strong absorption features and rich multi-electron redox electrochemistry. Their electrocatalytic oxygen reduction performance were examined by rotating ring disk electrode technique. The cobalt 10,10-dimethyl-5,15-bis(pentafluorophenyl)-isocorrole showed the highest water production yield form O2, which is 85%. ☐ Cobalt(III) macrocycles with alkyl or acetyl group as axial ligand also can serve as a radical source for polymerization reaction via irradiation or heating. The cobalt 10,10-dimethyl-5,15-bis(pentafluorophenyl)-isocorrole can be used as a cobalt precursor with phenethyl alcohol and sodium phosphate to realize the 1-phenethyloxycarbonyl cobalt 10, 10-dimethyl-5,15-bis(pentafluorophenyl)-isocorrole. It showed unique near IR absorption features and the radical dissociation process was approved by adding TEMPO as a radical trap when irradiated at 450 nm. This process is monitored by both NMR spectrometry and time related UV-vis experiment. The cobalt(II) precursor can be recycled after the irradiation. It also has potential applications for polymerization reactions or drug delivery process. ☐ Another series of tetrapyrrole scaffold with sp3 hybridized meso-carbon on the 10-position, biladiene derivatives which have methyl or phenyl substituents, were also investigated for its singlet oxygen sensitizer with palladium(II) metal center. It is interesting that even though the three complexes performed multi-electron redox electrochemistry, however, switching with one or both methyl groups to phenyl substituent didn’t change the redox potential, but their absorption features did increase when introducing more phenyl groups than methyl groups. It is also interesting that the palladium 10, 10-diphenyl-5,15-bis(pentafluorophenyl)-biladiene displayed the highest fluorescent quantum yield and singlet quantum yield, as well as the lowest phosphorus quantum yield. All the three palladium biladiene derivatives can be applied as potential photodynamic therapy sensitizers. | en_US |
| Advisor | Rosenthal, Joel | |
| Degree | Ph.D. | |
| Department | University of Delaware, Department of Chemistry and Biochemistry | |
| DOI | https://doi.org/10.58088/5and-hw73 | |
| Unique Identifier | 1244167598 | |
| URL | https://udspace.udel.edu/handle/19716/28868 | |
| Language | en | |
| Publisher | University of Delaware | en_US |
| URI | https://login.udel.idm.oclc.org/login?url=https://www.proquest.com/dissertations-theses/synthesis-nontraditional-tetrapyrrole-ligand/docview/2492632239/se-2?accountid=10457 | |
| Keywords | Oxygen reduction | en_US |
| Keywords | RRDE | en_US |
| Keywords | Singlet oxygen | en_US |
| Keywords | Small molecule activation | en_US |
| Title | Synthesis of nontraditional tetrapyrrole ligand platform for small molecule activation | en_US |
| Type | Thesis | en_US |