MSc., Faculty of Science, University of the Witwatersrand, 2011 / This dissertation presents the results of a crystallographic investigation into nineteen
novel n-aminopyridinium perhalometallates of the general formula (C5H7N2
+)2MX4
2-
where n = 2, 3 or 4, M = Zn, Cd or Hg and X = Cl, Br or I. The aim was to identify
positional effects of the cation hydrogen bonding donor groups on the structures and to
possibly identify robust synthons. Overall structural trends were also studied. The
hybrid crystals were synthesized using temperature controlled crystallization methods
and were characterized using X- ray diffraction techniques. Eighteen of the nineteen
hybrid crystals displayed isolated tetrahedral perhalometallate anions. The results were
classified into six different classes of isostructural compounds. Eight of the nineteen
hybrid structures (42%) contained water. The 42% include two 3-ammoniopyridinium
structures and all cadmium and mercury containing 4-aminopyridinium structures. The
effect of a change in metal and/ or halide on the structure was investigated, and the
overall structural trends in each n-aminopyridinium family were identified. Four
different synthons were observed in the 2-aminopyridinium series while one synthon
was observed throughout the 4-aminopyridinium series. A common synthon was
observed in both the 3-aminopyridinium and 3-ammoniopyridinium series.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:wits/oai:wiredspace.wits.ac.za:10539/11247 |
| Date | 06 February 2012 |
| Creators | Lawrence, Estee |
| Source Sets | South African National ETD Portal |
| Language | English |
| Detected Language | English |
| Type | Thesis |
| Format | application/pdf, application/pdf |
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