- Title
- The host potential of wheel-and-axle polyaromatic compounds
- Creator
- Vorgers, Jarryd Allister
- Subject
- Supramolecular chemistry
- Date Issued
- 2024-04
- Date
- 2024-04
- Type
- Master's theses
- Type
- text
- Identifier
- http://hdl.handle.net/10948/64426
- Identifier
- vital:73704
- Description
- In this work, wheel-and-axle compounds 1,4-phenylene-bis(diphenylmethanol) (H1), 1,4-phenylene-bis(di-p-tolylmethanol) (H2) and 1,4-phenylene-bis(di-p-fluorophenylmethanol) (H3) were investigated for their host behaviour in various pyridyl and heterocyclic guest mixtures. These host compounds were readily synthesized by means of Grignard addition reactions on dimethyl terephthalate, employing the aryl halides bromobenzene for H1 (73% yield), p-bromotoluene for H2 (69%) and p-bromofluorobenzene for H3 (70%). Molecular modelling calculations demonstrated that the various C-C-C angles differed between the computed low energy host conformers and those in the host molecules from their PYR-containing crystal structures. However, specified ‘torsion’ angles were in close agreement. Compound 1,4-phenylene-bis(diphenylmethanol) (H1) possessed the ability to form 1:2 host-guest (H:G) complexes with each of pyridine (PYR) and 2-, 3- and 4-methylpyridine (2MP, 3MP and 4MP). Furthermore, H1 showed preferential behaviour towards PYR and 4MP when presented with various mixtures of these four pyridines. Due to the high selectivity coefficients calculated in many instances (the selectivity coefficient, K, is a measure of the selectivity of a host compound for one particular guest in a mixture), it was demonstrated that H1 would be suitable for separations/purifications for many of the mixtures investigated in this work through host-guest chemistry strategies. (These pyridines are difficult to separate by means of the more conventional fractional distillations because of very similar boiling points.) Single crystal X-ray diffraction (SCXRD) analyses revealed that 4MP and 3MP experienced hydrogen bonds with the host molecule which were similar in distance, while the hydrogen bond distance between H1 and 4MP was shorter than that between H1 and 2MP. Furthermore, the hydrogen bond angles in complexes with the preferred PYR and 4MP guest species were more linear than in those having 2MP and 3MP. Additionally, preferred PYR and 4MP experienced significant π‧‧‧π contacts with nearby guest molecules, while disfavoured 2MP and 3MP did not interact in this fashion. Hirshfeld surface analyses demonstrated that PYR and 4MP (favoured) were involved in a greater percentage of (guest)N‧‧H(host)
- Description
- Thesis (MSc) -- Faculty of Science, School of Biomolecular & Chemical Sciences, 2024
- Format
- computer
- Format
- online resource
- Format
- application/pdf
- Format
- 1 online resource (xiii, 292 pages)
- Format
- Publisher
- Nelson Mandela University
- Publisher
- Faculty of Science
- Language
- English
- Rights
- Nelson Mandela University
- Rights
- All Rights Reserved
- Rights
- Open Access
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NMU School of BioMolecular and Chemical Sciences
| Thumbnail | File | Description | Size | Format | |||
|---|---|---|---|---|---|---|---|
| View Details Download | SOURCE1 | Vorgers, JA.pdf | 9 MB | Adobe Acrobat PDF | View Details Download |