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Guest uptake in porous metallocyclic host compounds
Thesis (PhD)--Stellenbosch University, 2020.
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| Format: | Thesis |
| Language: | en_ZA |
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Stellenbosch : Stellenbosch University
2020
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| _version_ | 1867614041466208256 |
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| access_status_str | Open Access |
| author | Du Plessis, Marike |
| author2 | Barbour, Leonard J. |
| author_browse | Barbour, Leonard J. Du Plessis, Marike |
| author_facet | Barbour, Leonard J. Du Plessis, Marike |
| author_sort | Du Plessis, Marike |
| collection | Thesis |
| dc_rights_str_mv | Stellenbosch University |
| description | Thesis (PhD)--Stellenbosch University, 2020. |
| format | Thesis |
| id | oai:scholar.sun.ac.za:10019.1/108355 |
| institution | Stellenbosch University (South Africa) |
| language | en_ZA |
| last_indexed | 2026-06-10T12:45:43.568Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from SUNScholar — Stellenbosch University Repository |
| publishDate | 2020 |
| publishDateRange | 2020 |
| publishDateSort | 2020 |
| publisher | Stellenbosch : Stellenbosch University |
| publisherStr | Stellenbosch : Stellenbosch University |
| record_format | dspace |
| source_str | SUNScholar — Stellenbosch University Repository |
| spelling | oai:scholar.sun.ac.za:10019.1/108355 Guest uptake in porous metallocyclic host compounds Du Plessis, Marike Barbour, Leonard J. Stellenbosch University. Faculty of Science. Dept. of Chemistry and Polymer Science. Crystalline polymers Porous materials Supramolecular chemistry UCTD Thesis (PhD)--Stellenbosch University, 2020. ENGLISH ABSTRACT: The general aim of the work discussed in this dissertation is to contribute to scientific knowledge, thereby broadening our understanding of the relationships between the structure of a solid, crystalline material and its properties. Only when we truly understand the principles of supramolecular chemistry might we be able to design crystals for targeted applications at will. Metallocycles are a sub-class of supramolecular materials studied by the Barbour group for their potential porosity. In this regard, we selected three previously reported metallocycles, known to be porous, with the specific aim of further probing their porosity by means of guest exchange experiments. The first metallocycle studied is a silver-based acetonitrile solvate with the formula [Ag2L12](BF4)2•2CH3CN, where L1 is the ligand 1,4-bis(2-methylimidazol-1-ylmethyl)benzene; we refer to this metallocycle asMC1•2CH3CN. It was shown that the acetonitrile guest molecules can be replaced by other small guest molecules, specifically acetone, dichloromethane, benzene, p-difluorobenzene and toluene by immersing the as-synthesised crystals in the liquid of the target guest. The second is a Cu-based metallocycle with dimethylsulfoxide (DMSO) coordinated to the metal centre. The formula for this metallocycle (referred to as MC2S2) is [Cu2Cl4L12S2], where S is the coordinated solvent. The coordination bond can be cleaved by replacing the DMSO with acetonitrile in a solvent exchange process. We have shown that, by exposing the acetonitrile inclusion compound (MC2•2CH3CN) to vapours of solids, inclusion compounds with pyrazine, p-benzoquinone, p-dichlorobenzene and naphthalene can be obtained. While MC1•2CH3CN and MC2S2 are constructed using the same ligand, the third metallocycle, [Cu2L22Cl4] or MC3, contains the ligand 1,3-bis(imidazol-1-ylmethyl)-2,4,6-trimethylbenzene (L2). Guest exchange experiments were carried out with MC3 and the three isomers of xylene. We have shown that p-xylene is selectively included from a mixture of the xylene isomers and that this metallocycle can be used to purify commercially pure o-xylene by extracting p-xylene impurities. All of the guest exchanges occurred as single-crystal to single-crystal transformations, allowing us to obtain crystal structures of the new inclusion compounds using single-crystal X-ray diffraction techniques. The crystal structures were analysed and insights gained from the crystal structures as well as supporting techniques such as thermogravimetric analysis, powder X-ray diffraction, ultraviolet-visible spectroscopy, Fourier transform infrared spectroscopy, vapour sorption, gas chromatography and nuclear magnetic resonance spectroscopy are discussed in this dissertation. AFRIKAANSE OPSOMMING: Die oorhoofse doel van die werk wat in hierdie proefskrif bespreek word, is om by te dra tot wetenskaplike kennis en sodoende ons begrip van die verwantskap tussen die struktuur van ’n kristallyne vastestof en die eienskappe van die materiaal, te verbreed. Eers wanneer ons werklik die beginsels van supramolekulêrechemie verstaan, sal ons moontlik hierdie beginsels kan gebruik om doelbewus kristalle te ontwerp vir geteikende toepassings. Metallosiklieseverbindings is ’n groepering van supramolekulêremateriale wat deur die Barbour groep bestudeer word vir hul potensiële poreuse eienskappe. Met dit in gedagte, het ons drie metallosiklieseverbindings gekies wat reeds as poreuse materiale bekend, asook gerapporteer, is met die doel om hierdie materiale verder te ondersoek deur middel van gas-uitruileksperimente. Die eerste metallosiklieseverbinding wat ons ondersoek het, is ’n silver-gebaseerde asetonitrielsolvaat met die formule [Ag2L12](BF4)2•2CH3CN, waar L1 die ligand 1,4-bis(2-metielimidasool-1-ilmetiel)benseen is. Ons verwys na hierdie metallosiklieseverbinding as MC1•2CH3CN. Dit is bewys dat die asetonitrielgasmolekules vervang kan word deur ander klein gasmolekules, spesifiek asetoon, dichloormetaan, benseen, p-difluoorbenseen en tolueen, deur die kristalle soos gesintetiseer in die vloeistof van die teikengas te onderdompel. Die tweede verbinding is ’n koper-gebaseerde metallosiklieseverbinding met dimetielsulfoksied (DMSO) gekoördineer aan die metaal. Die formule vir hierdie metallosiklieseverbinding (MC2S2) is [Cu2Cl4L12S2], waar S die gekoördineerde oplosmiddel is. Die koördinasiebinding kan gekloof word deur die DMSO met asetonitriel te vervang in ’n oplosmiddeluitruilingsproses. Ons het gewys dat insluitingsverbindings met pirasien, p-bensokinoon, p-dichloorbenseen en naftaleen verkry kan word deur die asetonitriel-insluitingsverbinding (MC2•2CH3CN) aan dampe van die verskeie vastestowwe bloot te stel. Terwyl MC1•2CH3CN en MC2S2 opgebou word met dieselfde ligand, bevat die derde metallosiklieseverbinding, [Cu2L22Cl4] of MC3, die ligand 1,3-bis(imidasool-1-ilmetiel)-2,4,6-trimetielbenseen (L2). Gas-uitruileksperimente is uitgevoer met MC3 en die drie isomere van xileen. Dit is aangetoon dat p-xileen selektief ingesluit word vanuit ’n mengsel van die xileen isomere en dat hierdie metallosiklieseverbinding gebruik kan word om kommersiële o-xileen te versuiwer deur die p-xileen onsuiwerhede te onttrek. Al die gas-uitruilings het as enkel-kristal tot enkel-kristal transformasies geskied, wat ons in staat gestel het om enkelkristal X-straaldiffraksie tegnieke te gebruik om kristalstrukture van die nuwe insluitingsverbindings te bekom. Die kristalstrukture is geanaliseer en nuwe insigte wat daaruit, sowel as uit ondersteunende tegnieke soos byvoorbeeld termogravimetriese analise, poeier X-straaldiffraksie, dampsorpsie, ultraviolet-sigbarespektroskopie, Fourier-transformasie-infra-rooispektroskopie, gaschromatografie en kernmagnetiese resonans-spektroskopie aan die lig gekom het, word in hierdie proefskrif bespreek. Doctoral 2020-01-20T13:34:41Z 2020-04-28T15:10:44Z 2020-01-20T13:34:41Z 2020-04-28T15:10:44Z 2020-01 Thesis http://hdl.handle.net/10019.1/108355 en_ZA Stellenbosch University xi, 143 pages : illustrations application/pdf Stellenbosch : Stellenbosch University |
| spellingShingle | Crystalline polymers Porous materials Supramolecular chemistry UCTD Du Plessis, Marike Guest uptake in porous metallocyclic host compounds |
| title | Guest uptake in porous metallocyclic host compounds |
| title_full | Guest uptake in porous metallocyclic host compounds |
| title_fullStr | Guest uptake in porous metallocyclic host compounds |
| title_full_unstemmed | Guest uptake in porous metallocyclic host compounds |
| title_short | Guest uptake in porous metallocyclic host compounds |
| title_sort | guest uptake in porous metallocyclic host compounds |
| topic | Crystalline polymers Porous materials Supramolecular chemistry UCTD |
| url | http://hdl.handle.net/10019.1/108355 |
| work_keys_str_mv | AT duplessismarike guestuptakeinporousmetallocyclichostcompounds |