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Structural characterisation of coordination compounds incorporating Imidazole-based ligands
Thesis (MSc)--Stellenbosch University, 2012.
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| Format: | Thesis |
| Language: | en_ZA |
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Stellenbosch : Stellenbosch University
2012
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| _version_ | 1867613737691643904 |
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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 (MSc)--Stellenbosch University, 2012. |
| format | Thesis |
| id | oai:scholar.sun.ac.za:10019.1/20393 |
| institution | Stellenbosch University (South Africa) |
| language | en_ZA |
| last_indexed | 2026-06-10T12:40:54.381Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from SUNScholar — Stellenbosch University Repository |
| publishDate | 2012 |
| publishDateRange | 2012 |
| publishDateSort | 2012 |
| publisher | Stellenbosch : Stellenbosch University |
| publisherStr | Stellenbosch : Stellenbosch University |
| record_format | dspace |
| source_str | SUNScholar — Stellenbosch University Repository |
| spelling | oai:scholar.sun.ac.za:10019.1/20393 Structural characterisation of coordination compounds incorporating Imidazole-based ligands Du Plessis, Marike Barbour, Leonard J. Stellenbosch University. Faculty of Science. Dept. of Chemistry and Polymer Science. Crystal polymers Supramolecular materials Metallocycles Coordination polymers Thesis (MSc)--Stellenbosch University, 2012. ENGLISH ABSTRACT: Crystal engineering is a relatively new and fast growing branch of science. It emanates from the field of supramolecular chemistry and involves the self assembly of molecular and/or ionic “building blocks” to form a crystal – i.e. a “supermolecule”. Ultimately, a crystal with a predetermined structure and properties may result from a shrewd choice of building blocks. The main objective of this study was to investigate the architectures formed by flexible imidazole derived ligands when combined with a range of transition metal salts. The specific architecture that we aim to obtain with these building blocks is the “doughnut”-shaped metallocycle. Stacking of metallocycles to form columns in the crystal is a design strategy for creating porous materials and it has proven to be successful on several occasions. The following organic ligands were synthesised as part of this work: - 1,4-bis(benzimidazol-1-ylmethyl)benzene - 4,4'-bis(benzimidazol-1-ylmethyl)biphenyl - 1,3-bis(benzimidazol-1-ylmethyl)-2,4,6-trimethylbenzene - 1,4-bis(benzimidazol-1-ylmethyl)tetrafluorobenzene - 1,4-bis-(2-methylimidazol-1-ylmethyl)benzene - 1,4-bis-(2-methylimidazol-1-ylmethyl)tetrafluorobenzene The coordination compounds that were obtained during the course of this study were mainly analysed using single-crystal X-ray diffraction (SCD). A total of 40 novel crystal structures were obtained, of which 13 are metallocycles, 26 are either 1D or 2D coordination polymers and one is a salt. Of the 13 metallocycles, seven have the conventional doughnut shape. However, the property of porosity was limited by certain factors, which are discussed. Preliminary results show that two of these metallocycles are potential candidates for porosity studies. Many of the crystal structures also provide excellent examples of isostructurality, solvatomorphism and supramolecular isomerism – i.e. different crystal forms. The latter terms refer to similarities in the packing arrangements of molecules in the solid state or different packing arrangements of the same molecules or building blocks, both common phenomena in supramolecular chemistry. In the context of crystal engineering, we are still far from being able to predict and control the outcome of a crystallisation experiment to obtain a specific crystal form. AFRIKAANSE OPSOMMING: Kristalingenieurswese is ‘n relatief nuwe en vinnig groeiende vertakking van die wetenskap. Dit vloei voort uit die veld genaamd supramolukulêre chemie en behels die self-samestelling van molekulêre en/of ioniese “boustene” om ‘n kristal – of in effek, “supermolekule”, te vorm. Die mikpunt is om, deur middel van ‘n ingeligte keuse van boustene, ‘n kristal met ‘n voorafbepaalde struktuur en gewensde eienskappe te verkry. Die primêre doel van hierdie studie was om die argitekture te ondersoek wat gevorm word wanneer buigbare imidasool-afgeleide ligande met ‘n reeks oorgangsmetaalsoute gekombineer word. Die spesifieke argitektuur wat ons hoop om met hierdie boustene te verkry, is die ringvormige metalosiklus. Die metalosiklusse pak saam om kolomme in die kristal te vorm. Hierdie manier van pak, is ‘n ontwerpstrategie om poreuse materiale te verkry en dit is al voorheen bewys om suksesvol te wees. Die volgende organiese ligande is gesintetiseer as deel van hierdie werk: - 1,4-bis(bensimidasool-1-ielmetiel)benseen - 4,4'-bis(bensimidasool-1-ielmetiel)bifeniel - 1,3-bis(bensimidasool-1-ielmetiel)-2,4,6-trimetielbenseen - 1,4-bis(bensimidasool-1-ielmetiel)tetrafluorobenseen - 1,4-bis-(2-metielimidasool-1-ielmetiel)benseen - 1,4-bis-(2-metielimidasool-1-ielmetiel)tetrafluorobenseen Die koördinasieverbindings wat gedurende die verloop van die studie verkry is, is hoofsaaklik geanaliseer met behulp van enkelkristal X-straal diffraksie. Veertig nuwe kristalstrukture is in totaal verkry, waarvan 13 metallosiklusse is, 26 is een- of tweedimensionele koördinasiepolimere en een is ‘n sout. Van die 13 metallosiklusse het sewe die konvensionele ring vorm. Ten spyte van die gewensde ring vorm is die eienskap van poreusheid beperk deur sekere faktore wat bespreek sal word. Voorlopige resultate wys dat twee van die metallosiklusse potensiële kandidate vir poreusheid-studies is. Baie van die kristalstukture is ook uitstekende voorbeelde van isostrukturaliteit, solvatomorfisme en supramolekulêre isomerisme – met ander woorde, verskillende kristalvorms. Die laasgenoemde terme verwys na ooreenkomste in die rangskikking van molekules in die vaste toestand, of verskillende rangskikkings van dieselfde molekules of boustene, beide algemene verskynsels in supramolekulêre chemie. In die konteks van kristalingenieurswese is dit steeds bykans onmoontlik om die uitkoms van ‘n kristalisasie eksperiment te voorspel en te beheer sodat ‘n spesifieke kristalvorm verkry kan word. Masters 2012-02-24T06:48:48Z 2012-03-30T11:10:27Z 2012-02-24T06:48:48Z 2012-03-30T11:10:27Z 2012-03 Thesis http://hdl.handle.net/10019.1/20393 en_ZA Stellenbosch University 160 pages application/pdf application/pdf Stellenbosch : Stellenbosch University |
| spellingShingle | Crystal polymers Supramolecular materials Metallocycles Coordination polymers Du Plessis, Marike Structural characterisation of coordination compounds incorporating Imidazole-based ligands |
| title | Structural characterisation of coordination compounds incorporating Imidazole-based ligands |
| title_full | Structural characterisation of coordination compounds incorporating Imidazole-based ligands |
| title_fullStr | Structural characterisation of coordination compounds incorporating Imidazole-based ligands |
| title_full_unstemmed | Structural characterisation of coordination compounds incorporating Imidazole-based ligands |
| title_short | Structural characterisation of coordination compounds incorporating Imidazole-based ligands |
| title_sort | structural characterisation of coordination compounds incorporating imidazole based ligands |
| topic | Crystal polymers Supramolecular materials Metallocycles Coordination polymers |
| url | http://hdl.handle.net/10019.1/20393 |
| work_keys_str_mv | AT duplessismarike structuralcharacterisationofcoordinationcompoundsincorporatingimidazolebasedligands |