No description available.

No description available.

No description available.

No description available.

No description available.

This thesis details the synthesis and characterisation of alkaline earth metal complexes of phosphonium ylides and iminophosphoranes, together with some related phosphine oxide species. This thesis also contains the synthesis and structural characterisation of a number of novel phosphonium ylides and iminophosphoranes. Chapter 1 provides an introduction to the field of phosphonium ylides and related compounds, describing their preparation and subsequent reactivity. Chapter 2 contains an explanation of the experimental techniques and analytical tools used, whilst Chapter 3 details the syntheses and analyses for all of the complexes discussed in the thesis. Chapter 4 discusses novel alkaline earth metal phosphonium ylide complexes. The chapter contains the first structurally characterised neutral phosphonium ylide complexes of calcium, strontium and barium with the general formula (Ph(_3)PCH(_2))(_2) M[N(SiMe(_3))(_2)](_2), where M = Ca, Sr and Ba. The analogous iminophosphorane and phosphine oxide complexes are discussed in detail in chapter 5. Complexes of the general formula (Ph(_3)PNH)(_2) M[0C(_6)H2(Me)(^1)Bu(_2)](_2),(Ph(_3)P0)(_2) M[0C(_6)H(_2)(Me)’Bu(_2)](_2) and (Ph(_3)PO)(_2) M[N(SiMe(_3))(_2)](_2), are described where M =Ca, Sr and Ba. Chapter 6 details the synthesis of novel litbiated iminophosphoranes and related compounds as well as the synthesis of a novel dianion [Ph(_2)(PhCH')PN"] for use in synthetic organic chemistry. The final Chapter (7) details the synthesis and structural characterisation of a number of novel phosphonium ylides Ph(_2)R'PCHR" and iminophosphoranes Ph(_2)R’’’PNH and their corresponding salts e.g Ph(_2)R'PTH(_2)R"X and Ph(_2)R 'P+NH(_2)X .

No description available.

No description available.

none

The study of the structure-activity relationship of electrode surfaces is fundamentally important in electrocatalysis research. Yet, the methods and techniques used for the examination of structure-activity relationship so far are limited by their capabilities, and the exploration of electrochemistry at complex surfaces is very challenging. In this study, the correlation between the electrode surface structure and its corresponding activity in two electrochemical reactions were investigated: an electrochemical etching reaction and an electrocatalysis reaction. A polycrystalline Pt electrode was galvanically etched to expose the underlying well-defined crystallites serving as pseudo-single-crystal electrodes. Atomic force microscopy (AFM) complemented with electron backscatter diffraction (EBSD) was employed for the elucidation of the effects of electrode surface structure on its etching rate. Electrochemical measurements of the electrocatalytic activity of the hydrogen oxidation reaction on individual grain surfaces were performed with high spatial resolution scanning electrochemical microscopy (SECM) coupled with electron backscatter diffraction (EBSD). The etching experiment and surface characterization results show the more deeply etched regions on polycrystalline Pt surface correspond to Pt(100). The etching rate of the Pt catalyst is Pt(111), Pt(100), and Pt(110) in increasing order. The structure-reactivity relationship showed that the catalytic activity for hydrogen oxidation reaction (HOR) increases in the order Pt(100) < Pt(110) < Pt(111), where the Miller index plane represents the terrace orientation of the high-index facets. A clear correlation is observed between the increase in HOR activity and step sites density on a given base orientation. Quantitative kinetic measurements at crystal domains were made from current-potential plots and SECM approach curves.