Characterization and dynamics of pyrene and gamma-cyclodextrin complexes of multiple stoichiometrics
| dc.contributor.author | Dyck, Andria Sara Marie | en_US |
| dc.date.accessioned | 2024-08-13T20:22:11Z | |
| dc.date.available | 2024-08-13T20:22:11Z | |
| dc.date.copyright | 2001 | en_US |
| dc.date.issued | 2001 | |
| dc.degree.department | Department of Chemistry | |
| dc.degree.level | Master of Science M.Sc. | en |
| dc.description.abstract | The pyrene/y-CD supramolecular guest/ host system was characterized using several photophysical techniques, and the dynamics were investigated using the stopped flow technique with fluorescence detection. This study was undertaken in order to better understand the dynamics involved in supramolecular systems containing complexes of multiple stoichiometry. In addition, the methodologies used in this study may be employed in future studies investigating the dynamics of other guest: CD supramolecular systems containing multiple stoichiometric complexes. The techniques used to characterize the system included absorption spectroscopy, fluorescence emission and excitation spectroscopy, quenching of the excited state using the iodide ion, and time-resolved spectroscopy. Results from these various techniques indicate that the supramolecular pyrene: y-CD complexes that are present are the 1: 1, 1 :2, and 2:2 complexes. Using a step-wise formation mechanism, the equilibrium constants are found to be 325 ± 25 M-1, 110 ± 30 M-t, and ( 1.5 ± 0.5) x 106 M-1 for these complexes, respectively (at 20 ° C). The dynamics of the pyrene: y-CD system were found to be quite complex. At lower host concentrations and at shorter time-bases, i.e. less than -10 x 10-3 My-CD and around 200 ms, respectively, the kinetics were semi-quantitatively explained by a dimerization model. The association rate constant for this process is found to be of the order of 107 M-1s-1, whereas the dissociation rate constant is approximately 10 to 102 s-1. At higher host concentrations, the kinetics were more complex at longer time-scales, i.e. > 100 ms to the minute time-scale. This was qualitatively found to be a result of the dynamics of the 1:2 complex. | |
| dc.format.extent | 103 pages | |
| dc.identifier.uri | https://hdl.handle.net/1828/17677 | |
| dc.rights | Available to the World Wide Web | en_US |
| dc.title | Characterization and dynamics of pyrene and gamma-cyclodextrin complexes of multiple stoichiometrics | en_US |
| dc.type | Thesis | en_US |
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