Thesis (MSc (Chemistry and Polymer Science))--University of Stellenbosch, 2009. / ENGLISH ABSTRACT:
This thesis reports an in-depth investigation of the intermolecular interaction motifs in
secondary, primary and ammonium carboxylate salts. The investigation was
conducted using the Cambridge Structural Database (CSD), together with a systematic
steric-specific experimental study.
The tendency in the literature has been to analyse organic salt crystal structures in
terms of hydrogen bonding patterns, almost ignoring cation-anion interactions. This
study focuses on the cation-anion interactions in secondary, primary and ammonium
carboxylate salts, which have a direct effect on the formation of specific structural
motifs. The ideas of ring-stacking and ring-laddering, which arise from the tendency
of cations and anions to arrange themselves so as to maximise electrostatic
interactions, have been applied to ammonium carboxylate salts.
An extensive survey of organic ammonium carboxylate salt structures in the CSD has
been carried out. The structural motifs in ammonium carboxylates were investigated,
and a set of predictive rules for the pattern of intermolecular interactions in these salts
was developed. Using these results, the formation of ring-stacking or ring-laddering in
primary ammonium carboxylate salts can be predicted. The results from the CSD
survey are discussed in Chapter 3.
An experimental study has been carried out, which complements the results obtained
from the CSD survey. The experimental study formed 19 novel ammonium
carboxylate salts, of which 2 formed hydrates and 2 co-crystals of salts. The
experimental results confirm what was found in the CSD survey, and this is discussed
in Chapter 4.
This study has found that the principle of ring-stacking and ring-laddering can be
applied in a general form to the crystal structures of organic ammonium carboxylate
salts. The size of the cation and the anion in these salts has a significant effect on the
formation of structural motifs in the solid state. Interactions between cation and anion
substituents also play an important role in the formation of particular structural motifs
in ammonium carboxylate salts. / AFRIKAANSE OPSOMMING:
In hierdie tesis word die intermolekulêre interaksie motiewe in die sekondêre, primêre
en ammonium karbosilaat soute in-diepte ondersoek. Die studie is gedoen met behulp
van die Cambridge Strukturele Databasis (CSD), saam met ‟n sistematiese steriesspesifieke
eksperimentele studie.
Die neiging in die literatuur is om organiese sout kristal strukture in terme van
waterstofbindings patrone te analiseer sonder om katioon-anioon interaksies in ag te
neem. Die studie fokus juis op hierdie katioon-anioon interaksies tussen sekondêre,
primêre en ammonium karbosilaat soute wat ‟n direkte effek het op die vorming van
spesifieke strukturele motiewe naamlik „ring-stacking‟ en „ring-laddering‟ wat hul
oorsprong kry vanaf die neiging van katione en anione om hulself op so ‟n wyse te
rangskik sodat die elektrostatiese interaksies ‟n maksimum kan bereik, op die
ammonium karboksilaat soute.
‟n Volledige ondersoek van ammonium karboksilaat soute in die CSD is gedoen. Die
strukturele motiewe in ammonium karboksilaat is ondersoek, en ‟n stel reels wat die
patrone van intermolekulêre interaksies in hierdie soute voorspelis ontwikkel. Hierdie
resultate kan gebruik word om die vorming van „ring-stacking‟ en „ring-laddering‟ in
primêre ammonium karbosilaat soute te voorspel. Die resultate van die CSD
ondersoek word bespreek in Hoofstuk 3.
‟n Eksperimentele studie is uitgevoer en die resultate hiervan komplimenteer die
resultate van die CSD ondersoek. In die eksperimentele studie is 19 nuwe ammonium
karboksilaat soute gekristaliseer, waarvan 2 hidraat-soute en 2 ko-kristal-van-soute is.
Die eksperimentele resultate bevestig die bevindings van die CSD ondersoek, en dit
word bespreek in Hoofstuk 4.
Hierdie studie het gevind dat die beginsel van „ring-stacking‟ en „ring-laddering‟ kan
in „n algemene vorm in die kristal strukture van organiese ammonium karboksilaat
soute toegepas word. Die grootte van die katioon en anion in hierdie soute het ‟n
beduidende effek op die vorming van strukturele motiewe in die vaste toestand.
Interaksie tussen die katioon en anioon substituente speel „n belangrike rol in die
vorming van spesifieke motiewe in ammonium karbosilaat soute.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:sun/oai:scholar.sun.ac.za:10019.1/2965 |
| Date | 12 1900 |
| Creators | Odendal, James Arthur |
| Contributors | Koch, Klaus R., Haynes, Delia A., University of Stellenbosch. Faculty of Science. Dept. of Chemistry and Polymer Science. |
| Publisher | Stellenbosch : University of Stellenbosch |
| Source Sets | South African National ETD Portal |
| Language | en_ZA |
| Detected Language | English |
| Type | Thesis |
| Rights | University of Stellenbosch |
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