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Synthesis and characterisation of silver(I) halo-pyridyl compounds: a study of the prominent NCIs that govern crystal packing

This study aimed to identify which non-covalent interactions (NCIs) would dominate in the solid-state structures of silver(I) halopyridyl compounds. Five novel compounds were synthesised and several metal involved NCIs were observed. The five compounds which formed a cohesive series are: [Ag2(OBn)2...

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Main Author: Theunissen, Tristan
Other Authors: Bourne, Susan
Format: Thesis
Language:English
English
Published: Department of Chemistry 2026
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access_status_str Open Access
author Theunissen, Tristan
author2 Bourne, Susan
author_browse Bourne, Susan
Theunissen, Tristan
author_facet Bourne, Susan
Theunissen, Tristan
author_sort Theunissen, Tristan
collection Thesis
description This study aimed to identify which non-covalent interactions (NCIs) would dominate in the solid-state structures of silver(I) halopyridyl compounds. Five novel compounds were synthesised and several metal involved NCIs were observed. The five compounds which formed a cohesive series are: [Ag2(OBn)2], [Ag2(2 Pic)2(OBn)2], [Ag2(3-Clpy)2(OBn)2], [Ag2(2-Brpy)2(OBn)2], and [Ag2(2-Ipy)2(OBn)2]. X-ray diffraction analysis of single crystals constituted the solid-state study portion of the NCIs. Their influence on the crystal structure was carried out using modern computational techniques, such as molecular electrostatic surface potential (MESP), natural bond orbital or NBO analysis, and quantum theory of atoms in molecules (QTAIM). This dissertation comprises four sections, the first of which introduces background knowledge on particular topics such as crystal engineering, non-covalent interactions, and possible applications that NCIs have within crystal engineering and supramolecular chemistry. The second and third sections discuss specific methods and techniques used to study the NCIs from a crystallographic and computational viewpoint. The final section summarises the contribution of the authors' work to the understanding and body of knowledge of NCIs. As shown in this dissertation, the ‘self-assembled' [Ag2(OBn)2(Xpy)2] compounds are closely related to their strongest non-covalent metal-involved interactions, such as AgI···π, AgI···X, and AgI···AgI, while also being influenced by weaker interactions', π···π, cooperativity effects. The importance of orbital-based charge transfers as opposed to being purely electrostatic in the argentophilicity of compounds I-V has been discussed. In this study, quantitative QTAIM, NBO, and MEPS-based analyses were carried out on the metallophilic (M+···M+) interactions. The computational studies suggest a greater role of orbital-based interactions in the strength and distance of said interactions. This hypothesis was applied to other NCIs, such as semi-coordination and metal-π NCIs, in which orbital-based charge-transfers are also shown to predominate force stabilising the compounds over pure electrostatic interactions. Compounds VI-VIII, although not included within the main series (I-V) display a variety of similar NCIs, as evident from their single-crystal structures, whose natures or characteristics are formed from the foundations of computations I-V. Prominent NCIs are AgI···π, AgI···X, and AgI···AgI, which are also influenced by weaker interactions', π···π, cooperativity effects.
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license_str Not specified — see source repository
provenance_str_mv Harvested via OAI-PMH from UCTD — University of Cape Town Open Access Repository
publishDate 2026
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spelling oai:open.uct.ac.za:11427/43208 Synthesis and characterisation of silver(I) halo-pyridyl compounds: a study of the prominent NCIs that govern crystal packing Theunissen, Tristan Bourne, Susan Esterhuysen, Catharine Crystallography Non-covalent interactions Semi-coordination bonding Metal-involved NCIs nucleophilic metal centres Silver(I) compounds Argentophilicity Density functional theory DFT This study aimed to identify which non-covalent interactions (NCIs) would dominate in the solid-state structures of silver(I) halopyridyl compounds. Five novel compounds were synthesised and several metal involved NCIs were observed. The five compounds which formed a cohesive series are: [Ag2(OBn)2], [Ag2(2 Pic)2(OBn)2], [Ag2(3-Clpy)2(OBn)2], [Ag2(2-Brpy)2(OBn)2], and [Ag2(2-Ipy)2(OBn)2]. X-ray diffraction analysis of single crystals constituted the solid-state study portion of the NCIs. Their influence on the crystal structure was carried out using modern computational techniques, such as molecular electrostatic surface potential (MESP), natural bond orbital or NBO analysis, and quantum theory of atoms in molecules (QTAIM). This dissertation comprises four sections, the first of which introduces background knowledge on particular topics such as crystal engineering, non-covalent interactions, and possible applications that NCIs have within crystal engineering and supramolecular chemistry. The second and third sections discuss specific methods and techniques used to study the NCIs from a crystallographic and computational viewpoint. The final section summarises the contribution of the authors' work to the understanding and body of knowledge of NCIs. As shown in this dissertation, the ‘self-assembled' [Ag2(OBn)2(Xpy)2] compounds are closely related to their strongest non-covalent metal-involved interactions, such as AgI···π, AgI···X, and AgI···AgI, while also being influenced by weaker interactions', π···π, cooperativity effects. The importance of orbital-based charge transfers as opposed to being purely electrostatic in the argentophilicity of compounds I-V has been discussed. In this study, quantitative QTAIM, NBO, and MEPS-based analyses were carried out on the metallophilic (M+···M+) interactions. The computational studies suggest a greater role of orbital-based interactions in the strength and distance of said interactions. This hypothesis was applied to other NCIs, such as semi-coordination and metal-π NCIs, in which orbital-based charge-transfers are also shown to predominate force stabilising the compounds over pure electrostatic interactions. Compounds VI-VIII, although not included within the main series (I-V) display a variety of similar NCIs, as evident from their single-crystal structures, whose natures or characteristics are formed from the foundations of computations I-V. Prominent NCIs are AgI···π, AgI···X, and AgI···AgI, which are also influenced by weaker interactions', π···π, cooperativity effects. 2026-05-08T11:33:46Z 2026-05-08T11:33:46Z 2023 2026-05-08T10:46:48Z Thesis / Dissertation Masters Masters http://hdl.handle.net/11427/43208 en eng application/pdf Department of Chemistry Faculty of Science University of Cape Town
spellingShingle Crystallography
Non-covalent interactions
Semi-coordination bonding
Metal-involved NCIs
nucleophilic metal centres
Silver(I) compounds
Argentophilicity
Density functional theory
DFT
Theunissen, Tristan
Synthesis and characterisation of silver(I) halo-pyridyl compounds: a study of the prominent NCIs that govern crystal packing
thesis_degree_str Master's
title Synthesis and characterisation of silver(I) halo-pyridyl compounds: a study of the prominent NCIs that govern crystal packing
title_full Synthesis and characterisation of silver(I) halo-pyridyl compounds: a study of the prominent NCIs that govern crystal packing
title_fullStr Synthesis and characterisation of silver(I) halo-pyridyl compounds: a study of the prominent NCIs that govern crystal packing
title_full_unstemmed Synthesis and characterisation of silver(I) halo-pyridyl compounds: a study of the prominent NCIs that govern crystal packing
title_short Synthesis and characterisation of silver(I) halo-pyridyl compounds: a study of the prominent NCIs that govern crystal packing
title_sort synthesis and characterisation of silver i halo pyridyl compounds a study of the prominent ncis that govern crystal packing
topic Crystallography
Non-covalent interactions
Semi-coordination bonding
Metal-involved NCIs
nucleophilic metal centres
Silver(I) compounds
Argentophilicity
Density functional theory
DFT
url http://hdl.handle.net/11427/43208
work_keys_str_mv AT theunissentristan synthesisandcharacterisationofsilverihalopyridylcompoundsastudyoftheprominentncisthatgoverncrystalpacking