Syntheses and characterization of copper(I) complexes for study of dynamic supramolecular ring-chain equilibria and application as photoredox catalysts
| dc.contributor.committeeChair | Mayer, Michael F. | |
| dc.contributor.committeeMember | Birney, David M. | |
| dc.contributor.committeeMember | Findlater, Michael | |
| dc.contributor.committeeMember | Webb, Mark | |
| dc.creator | Cetin, Muhammet Mustafa | |
| dc.creator.orcid | 0000-0002-6443-0232 | |
| dc.date.accessioned | 2022-04-05T22:24:05Z | |
| dc.date.available | 2022-04-05T22:24:05Z | |
| dc.date.created | 2017-08 | |
| dc.date.issued | 2017-08 | |
| dc.date.submitted | August 2017 | |
| dc.date.updated | 2022-04-05T22:24:06Z | |
| dc.description.abstract | The concept of a molecule as an assembly of atoms held together by covalent and/or non-covalent bonds is a key intellectual unit in chemistry. Molecular self-assembly (intermolecular self-assembly) is a spontaneous association of molecules in which molecules may form stable and structurally well-defined aggregates through non-covalent bonds under equilibrium conditions. This is a key concept in supramolecular chemistry. Many chemists, inspired by nature and life, have studied various aspects of non-covalent interactions in molecular assemblies. By employing weak intermolecular forces, chemists have notably achieved kinetic and thermodynamic control in syntheses. The utilization of non-covalent interactions in addition to covalent chemistry has led to new kinds of molecules called mechanically-interlocked molecules (MIMs), such as rotaxanes, catenanes and pseudorotaxanes. The discovery of 1,10-phenanthroline and its use as a ligand for application in the coordination and supramolecular chemistry fields dates back to the late nineteenth century. As ligands, 1,10-phenanthroline (and numerous substituted derivatives) strongly coordinate to most of the transition metal ions as fairly powerful σ-donors and π-acceptors. Thus, these ligands and their complexes, especially copper(I) complexes, have been the subject of a multitude of studies in organic, inorganic and supramolecular chemistry. By using the chelation of copper(I) ion species to phenanthroline ligands and its derivatives, a metalated [2]pseudorotaxane, a metalated [2]catenane and a metalated [2]rotaxane have been synthesized in order to access a demetalated [2]rotaxane. In Chapter 1, the synthesis of a metal-free, mechanically-interlocked [2]rotaxane molecule is described. In the synthetic route to the [2]rotaxane, a copper-chelated [2]catenane was induced to partake in a dynamic ring-chain equilibration in the presence of an acyclic chain transfer agent, with bulky chain ends, to yield a copper-chelated [2]rotaxane. A catalytic olefin metathesis was utilized to effect the dynamic ring-chain equilibration with an accompanying chain transfer. Various reaction conditions were screened in order to minimize competitive polymerization of the [2]catenane and to optimize the yield of the desired product, i.e. the metalated [2]rotaxane. Under optimal conditions, the copper-chelated [2]rotaxane was isolated in 88% yield. Mechanical entanglement of the spectator macrocycle was maintained over the course of the synthesis, from metalated [2]catenane to metalated [2]rotaxane, via copper chelation of the spectator macrocycle, despite acyclic reaction intermediates that lack bulky chain ends. After removal of the copper ion from the isolated metalated [2]rotaxane, the stable, demetalated, [2]rotaxane was obtained wherein the ring and chain were bonded only by mechanical entanglement. In Chapter 2, the synthesis, characterization, photophysical properties, theoretical calculations, and catalytic applications of 2,9-di(aryl)-1,10-phenanthroline copper (I) complexes are described. Specifically, this study made use of di(aryl)-1,10-phenanthroline ligands including 2,9-di(4-methoxyphenyl)-1,10-phenanthroline (2-1), 2,9-di(4-hydroxyphenyl)-1,10-phenanthroline (2-2), 2,9-di(4-methoxy-3-methylphenyl)-1,10-phenanthroline (2-3), and 2,9-di(4-hydroxy-3-methylphenyl)-1,10-phenanthroline (2-4). The 2:1 ligand-to-metal complexes, as PF6- salts, i.e., 2-5–2-8 have been isolated and characterized. The structures of ligands 2-1 and 2-2 and complexes 2-5 and 2-7 have been determined by single-crystal X-ray analysis. The photoredox catalytic activity of these copper (I) complexes was investigated in an atom-transfer radical addition (ATRA) reaction and the results showed fairly efficient activity, with a strong wavelength dependence. In order to better understand the observed catalytic activity, photophysical emission and absorption studies, and DFT calculations were also performed. It was determined that when the excitation wavelength was appropriate for exciting into the LUMO+1 or LUMO+2, catalysis would occur. On the contrary, excitations into the LUMO resulted in no observable catalysis. In light of these results, a mechanism for the ATRA photoredox catalytic cycle has been proposed. Additionally, in order to use possible alternative reaction media in organic transformations, synthesis and structural characterization of both symmetrical and unsymmetrical imidazolium-based ionic liquids (ILs) have been studied, as described in Chapter 3. The desired products were characterized by 1H NMR, 13C NMR and 19F NMR spectroscopy. The solid state structures of some ILs have been determined by single-crystal X-ray analysis. In the solid state structures, it has been observed that the size of the anion in the IL crystals of 3-10–3-12 affected the packing of the ions in their crystal lattices. All synthesized and characterized ILs have been used in different studies and applications by the Mayer, Quitevis and Simon research groups. | |
| dc.format.mimetype | application/pdf | |
| dc.identifier.uri | https://hdl.handle.net/2346/88942 | |
| dc.language.iso | eng | |
| dc.rights.availability | Access is not restricted. | |
| dc.subject | [2]Rotaxane | |
| dc.subject | [2]Catenane | |
| dc.subject | [2]Pseudorotaxane | |
| dc.subject | Dynamic Supramolecular Ring-Chain Equilibria | |
| dc.subject | Photoredox Catalysts | |
| dc.subject | Supramolecular Chemistry | |
| dc.subject | Synthesis | |
| dc.subject | Copper(I) Complexes | |
| dc.subject | 1,10-Phenanthroline Ligands | |
| dc.title | Syntheses and characterization of copper(I) complexes for study of dynamic supramolecular ring-chain equilibria and application as photoredox catalysts | |
| dc.type | Thesis | |
| dc.type.material | text | |
| thesis.degree.department | Chemistry and Biochemistry | |
| thesis.degree.discipline | Chemistry | |
| thesis.degree.grantor | Texas Tech University | |
| thesis.degree.level | Doctoral | |
| thesis.degree.name | Doctor of Philosophy |