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Thermal and mechanical responsiveness of some 4-substituted benzonitriles
Thesis (PhD)--Stellenbosch University, 2018.
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| Format: | Thesis |
| Language: | en_ZA |
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Stellenbosch : Stellenbosch University
2018
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| _version_ | 1867613966769848320 |
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| access_status_str | Open Access |
| author | Alimi, Lukman Olawale |
| author2 | Barbour, Leonard J. |
| author_browse | Alimi, Lukman Olawale Barbour, Leonard J. |
| author_facet | Barbour, Leonard J. Alimi, Lukman Olawale |
| author_sort | Alimi, Lukman Olawale |
| collection | Thesis |
| dc_rights_str_mv | Stellenbosch University |
| description | Thesis (PhD)--Stellenbosch University, 2018. |
| format | Thesis |
| id | oai:scholar.sun.ac.za:10019.1/104826 |
| institution | Stellenbosch University (South Africa) |
| language | en_ZA |
| last_indexed | 2026-06-10T12:44:33.029Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from SUNScholar — Stellenbosch University Repository |
| publishDate | 2018 |
| publishDateRange | 2018 |
| publishDateSort | 2018 |
| publisher | Stellenbosch : Stellenbosch University |
| publisherStr | Stellenbosch : Stellenbosch University |
| record_format | dspace |
| source_str | SUNScholar — Stellenbosch University Repository |
| spelling | oai:scholar.sun.ac.za:10019.1/104826 Thermal and mechanical responsiveness of some 4-substituted benzonitriles Alimi, Lukman Olawale Barbour, Leonard J. Smith, Vincent J. Stellenbosch University. Faculty of Science. Dept. of Chemistry and Polymer Science. Benzonitriles UCTD Thermal expansion -- Volumetry Molecular volume Thesis (PhD)--Stellenbosch University, 2018. ENGLISH ABSTRACT: This work is based on three publications. The first manuscript describes the large volumetric thermal expansion of an organic cocrystal over a wide range of temperature (100–300 K). The novel organic multicomponent crystal (cocrystal) (ABN·2DMABN) consisting of 1:2 molar ratio of 4-aminobenzonitrile (ABN) and 4-(dimethylamino)benzonitrile (DMABN) was prepared. It shows linear positive thermal expansion (PTE) along all its three principal axes over the temperature range 100–300 K, which is exclusively dependent on the intermolecular interactions that govern the crystal packing. The associated volumetric thermal expansion coefficient (αv) of 222 MK-1 is the largest reported to date for a cocrystal over such a wide temperature range. The second manuscript explains the mechanical response/behaviour of a rigid small organic molecule, 4-bromobenzonitrile (4-BBN) that has been crystallised using sublimation under dynamic vacuum (0.02 mbar). Interestingly, the crystals show highly flexible plastic behaviour and bends along two orthogonal faces under mechanical stress− a rare phenomenon, resulting in helical twisting, or coiling, which is also rare for crystals of such rigid small organic molecules. The third manuscript discusses the thermal behaviour of the purely organic material 4-aminobenzonitrile (ABN). The single crystals of ABN undergo reversible thermosalience upon cooling from 300 to 100 K and subsequent heating to 300 K. In this study we have demonstrated that the release of accumulated strain in these crystals upon cooling, which results in rapid structural rearrangement, is due to the interplay between the directional and non-directional intermolecular interactions in the system. AFRIKAANSE OPSOMMING: Geen opsomming beskikbaar Doctoral 2018-07-17T11:53:16Z 2018-12-07T06:46:47Z 2018-07-17T11:53:16Z 2018-12-07T06:46:47Z 2018-12 Thesis http://hdl.handle.net/10019.1/104826 en_ZA Stellenbosch University application/pdf Stellenbosch : Stellenbosch University |
| spellingShingle | Benzonitriles UCTD Thermal expansion -- Volumetry Molecular volume Alimi, Lukman Olawale Thermal and mechanical responsiveness of some 4-substituted benzonitriles |
| title | Thermal and mechanical responsiveness of some 4-substituted benzonitriles |
| title_full | Thermal and mechanical responsiveness of some 4-substituted benzonitriles |
| title_fullStr | Thermal and mechanical responsiveness of some 4-substituted benzonitriles |
| title_full_unstemmed | Thermal and mechanical responsiveness of some 4-substituted benzonitriles |
| title_short | Thermal and mechanical responsiveness of some 4-substituted benzonitriles |
| title_sort | thermal and mechanical responsiveness of some 4 substituted benzonitriles |
| topic | Benzonitriles UCTD Thermal expansion -- Volumetry Molecular volume |
| url | http://hdl.handle.net/10019.1/104826 |
| work_keys_str_mv | AT alimilukmanolawale thermalandmechanicalresponsivenessofsome4substitutedbenzonitriles |