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Organic electronics have received significant development in the last few decades. p- Type materials are much more in availability than n-type now. There are only a few examples of air-stable n-type materials. The design and synthesis of novel air-stable ntype materials is still a focus of research. Herein is described a study to evaluate the effectiveness of a novel electron-withdrawing group, composed of three electronwithdrawing groups connected in series, to impart material properties known to be favorable for obtaining air-stable n-types. The smaller acenes, naphthalene and anthracene, carrying these electron-withdrawing groups were prepared and studied by UV-Vis absorption spectroscopy and solution electrochemical measurements to estimate changes in frontier molecular orbital energies and single crystal X-ray diffraction to determine packing motif. These measurements suggest that the new materials could be promising as n-type semiconductors in organic field effect transistor (OFET) and as acceptors for organic photovoltaic (OPV) cells. The reasons are based on: (1) the close intermolecular contacts seen in X-ray crystal structures, some of them showing 3D faceto- face stack. (2) Electrochemical measurements indicate LUMO energy levels suitable for air-stable n-type materials.

This thesis describes the design, synthesis and reactivity of bimetallic complexes of doubly-pillared Schiff-base calixpyrrole ligands. Chapter One introduces the oxygen reduction reaction in light of the global energy scenario at present and in the future. Compounds and materials known to catalyse this reaction are discussed, with particular focus on transition metal complexes of pyrrole-containing macrocycles and the ability of these compounds to act as catalysts in redox reactions. Chapter Two describes the design and synthesis of several of the macrocyclic ligands developed during this project. The wide range of metals and geometries supported by one of the ligands, H4L, are outlined and include complexes of alkali-metals (Li, K), a rare earth metal (Mg), transition metals (Pd, Fe) and an actinide (UO2 2+). Chapter Three presents the use of [Co2(L)] for the reduction of dioxygen to water. The redox behaviour of the complex and its ability to reversibly bind oxygen were evaluated. The catalytic activity of [Co2(L)] was investigated in solution by UV-Vis spectrophotometry and electrochemically by rotating ring-disk electrochemistry. In Chapter Four, the ability of [Zn2(L)] to bind anions is described. Isothermal microcalorimetry, NMR, UV-Visible spectrophotometry, and fluorophotometry were used to study the de-aggregation of the anion free complex and the subsequent anion binding event. The stability of the complexes was estimated by DFT calculations. Chapter Five outlines the synthesis of complexes of L for other transition metals relevant to small molecule activation. Chapter Six contains a conclusion and suggestions on further investigations to carry out. Chapter Seven presents the full experimental details and analytical data for this work.