Spelling suggestions: "subject:"orford"" "subject:"herford""
1 |
The Character and Origin of the Soil Tongues in the Burford Loam / Soil Tongues In The Burford LoamGrubb, Alquin Meirion Jacob 04 1900 (has links)
<p> A pedological investigation was made of the soil tongues in the Burford loam soils of S. W. Ontario. The purpose of the study was to determine the characteristic features of the soil tongues. The physical and chemical properties of a number of soil tongues were determined and one was used for a micromorphological investigation. Measurements of horizontal and vertical extent were also made. Discussion of the various hypotheses that might account for soil tongue development is included. Evidence for a periglacial climate is given and also f'or the existence of two distinct types of soil tongues. </p> / Thesis / Master of Science (MSc)
|
2 |
Phosphorus (III) tricationic and dicationic complexesSinclair, Hannah 01 August 2017 (has links)
Coordination chemistry usually applies to transition metals, but has recently been extended to the p-block elements. For the pnictogen atoms (group 15), this type of coordination chemistry has already been applied to antimony and bismuth, where they behave as Lewis acceptor centres. However, complexes with nitrogen and phosphorus as Lewis acidic centres are rare, due to their relatively small atomic radii and inherent basic nature. Instead, these elements (Pn(III)) are typically observed as donor centres because they are better at donating their electron pair, than they are at accepting them. To enhance the Lewis acidity at the phosphorus and nitrogen centres, a cationic charge can be introduced by heterolytically abstracting a halide and replacing it with a weakly coordinating anion, providing more opportunities for new reactivity. The presence of a stereochemically active lone pair at the acceptor site also introduces new reactivity patterns to be explored. The formation of these main group coordination complexes opens doors to potential applications in catalysis, small molecule activation, or as material precursors. 2,2’-bipyridine (bipy) has been a prototypical ligand used in transition metal coordination chemistry due to its high basicity and oxidative resistance. This property has been exploited to enable a comprehensive study of a series of Pn(III) tricationic and dicationic complexes using 2,2’-bipyridine (bipy); 4,4’-di-tert-butyl-2,2’-bipyridine (tBu2bipy); 4-dimethylaminopyridine (DMAP); and other main group containing ligands. / Graduate
|
Page generated in 0.0379 seconds