No description available.

This thesis presents the design and structure of a number of Schiff-base pyrrole macrocycles, their use in the formation of mono- and dinuclear calcium complexes, and reactions with various alkali- and transition metals to form mixed-metal clusters. Chapter One introduces the range of Schiff-base macrocycles with tuneable properties for various synthetic applications. Previously reported complexes of various s-, d- and f-block metals in these macrocyclic frameworks are also discussed. Research into calcium chemistry is reviewed, both in catalysis of synthetic organic processes, and in synthetic modelling of reaction clusters found in protein structures. Chapter Two details the synthesis of three monometallic calcium complexes utilising Schiff base macrocycles H4LEt and H4LA, and dipyrrin ligand HLD. Reactions of Ca(THF)2(H2LEt) with transition metal halides and amines is outlined, leading to the formation of M2(LEt) (M = Fe, Co, Cu). Deprotonation of Ca(THF)2(H2LEt) with alkali metal amines forms calcium-alkali metal complexes; further reactivity of these with transition metal halides demonstrates unusual stoichiometry in the synthesis of mixed-metal clusters. Some of these complexes were assessed for catalytic activity in the hydroamination of isocyanates. Chapter Three describes the synthesis and characterisation of bimetallic calcium complexes of the ligands H4LEt, H4LA and H4LS5. Reactions of Ca2(THF)2(μ- THF)(LEt) with a range of small molecules - including H2O, LiOH and KOH - is outlined. In particular, reactivity of Ca2(THF)2(μ-THF)(LEt) with NaOH yielded calcium-alkali metal clusters Ca2(THF)2(μ-OH)(Na{THF}2)(LEt) and Ca2(THF)2(μ- OH)2(Na{THF})2(LEt), which displayed alternate wedged and bowl-shaped conformations of the macrocycle ligand. Further homobimetallic complex syntheses of M2(LEt) (M = Sn, Mn, Sr) are also outlined for comparison to calcium complexes. Chapter Four presents a summary of the work presented in this thesis, and Chapter Five outlines the full experimental procedures and analytical data for all described complexes.

This work investigated the use of large tetradentate mixed nitrogen and oxygen donor macrocycles as potential ligands for titanium(IV).These large ligands are capable of encapsulating the metal ion, thereby protecting it from reacting further. In addition, titanium complexes of this type had not been reported previously.Molecular modelling was utilised to evaluate and predict the coordinating potential of the macrocycles investigated.An alternative synthetic strategy was needed to achieve coordination complexes with titanium. This involved the use of a benzene based solvent system and rigorously dry reaction conditions.The final part of the work involved a detailed study of the kinetics of the hydrolysis of the titanium complexes investigated. / Doctor of Philosophy (PhD)

Commonly viewed as the shortest cross sections of armchair carbon nanotubes (CNTs), cycloparaphenylenes (CPPs) represent a unique class of conjugated macrocycles with rigid backbones. In addition to their utility in seeding the growth of uniform CNTs, these strained nanohoops and their derivatives have unique optoelectronic and supramolecular properties for potential applications in materials science. Herein we present our efforts in designing novel nanohoop architectures and new types of strained macrocycles that serve as building blocks for functional materials. Chapter I briefly reviewed the under-represented reactivity studies of strained aromatic macrocycles. Chapter II describes our early efforts in probing the structure-property relationships of oligophenylene macrocycles focusing on the understanding of the influence of structural bending and cyclic conjugation on the optoelectronic properties. Chapter III reports the reactivity study of 1,4-anthracene-incorporated [12]CPP, a model substrate to examine the feasibility of using anthracene as the functional handle to crosslink nanohoops. Chapter IV presents the synthesis of a molecular propeller with three nanohoop blades and examines its unique hexagonal layered packing structure. In Chapter V, we disclose the synthesis of strained stilbene macrocycles suitable for ring-opening metathesis polymerization (ROMP) as well as the initial ROMP studies of this monomeric system. This dissertation contains previously published and unpublished coauthored materials.

xxi, 294 p. ill. (some col.) A print copy of this title is available through the UO Libraries under the call number: SCIENCE QD403.O23 2008 / Highly conjugated carbon-rich systems have demonstrated many attractive applications for fundamental and materials science applications, including--but not limited to--probes for aromaticity, charge-transfer complexes, conducting/semi-conducting materials, linear/nonlinear optical materials, and solar cells. The bulk of this research has focused on carbon-rich fullerenes, conjugated polymers, or polycyclic aromatic hydrocarbons; however, with recent developments in cross-coupling chemistry, carbon rich chemistry, particularly dehydrobenzo[ n ]annulenes (DBAs), has grown to yield molecules of great diversity and utility. Concurrently, materials based on conjugated heterocycles have been developed and display similar and often enhanced properties to the aforementioned carbon rich systems. The lone pair of the heterocycle often adds additional stability and polarizablity, creating novel and tunable molecules. Assimilating techniques used to produce DBAs with heteroaromatic molecules, our work has afforded a novel class of conjugated macrocycles with the highly tunable optical-electronic properties of a DBA system. That in turn has led to the systematic study of the diverse structure-property relationships of the thiophene/DBA hybrids reported herein. Chapter I details the synthetic advances in the field of DBA chemistry. The first section discusses the methods of synthesis, inter- vs. intra- molecular approaches, while the remaining sections provide current examples of the DBAs reported. Chapter II briefly discuses conjugated thiophene chemistry, then describes the advantages of utilizing planarized thiophenes. Several examples of thiophene macrocycles are reviewed: both planar and nonplanar. Particular attention in the review focuses on synthesis, optical properties, and some redox properties. Chapters III and IV detail the synthesis and analysis of thiophenes locked into [14]- and [15]annulene scaffolds, respectively. The dehydrothieno[14]annulenes (DTAs) and DTA/DBA hybrids of chapter III serve as aromatic probes and show significant tunabilty with respect to the number and orientation of the thiophenes. Chapter IV's dehydrobenzo[15]annulenes, which are comprised of a cross-conjugated system, also display a structure-property relationship where the optical properties encompass a wider dispersion of wavelengths. Chapter IV also explores the incorporation of pyridines and the affects on conjugation. The electronic properties of the macrocycles were explored using NMR, UV-Vis absorption and fluorescence spectroscopy, and electrochemically (cyclic voltammetry). Chapter V is devoted to further functionalization of DTAs through alkylation and further cycliziation to yield planarized terthiophene units. This dissertation includes my previously published and co-authored material. / Adviser: Michael M. Haley

The present thesis mainly proposes to explore the potential of aza-macrocycles in metal-organic frameworks (MOFs) for applications related to unprecedented open macrocycle cavities. Strategies such as direct arylation of secondary amines as well as multidentate coordination were applied to constrain the intramolecular flexibility of as-obtained macrocyclic compounds. Several desired materials, i.e. MMCF-4, MMCF-5/MMCF-5t/MMCF-5t-aa, MMCF-5, HMMCF-1, were obtained. They are proved superior to traditional materials in the field of "turn-on" lanthanide luminescence, deep desulfurization of flue gas, recovery of Platinum-group metals, etc. Powder/single-crystal X-ray diffraction (PXRD/SCXRD), synchrotron-based X-ray and extended X-ray absorption fine structure (EXAFS), density functional theory (DFT) theoretical calculations, etc., were employed for deep-understanding the mechanisms. These studies shed light on the construction of hierarchically porous materials with two levels of porosity, i.e., one from the frameworks and the other one from the aza-macrocycles. Incorporation of aza-macrocycles into the MOF architectures not only leads to fundamental significance in bridging the chemistry of MOFs with supramolecular chemistry but also elicits unique properties from the hybrid materials obtained. As a paradigm for constructing frameworks with accessible macrocyclic cavities based on "constrained" aza-macrocycle ligands, this thesis paves the way for the further development of this framework family in the future.

No description available.

This research was focused on the study of the polymer dormant radical systems, species containing free radical structures that have longer lifetimes and greater stability than radicals in general. In order to understand the nature and reactivity of the dormant radicals, polymeric systems capable of producing dormant free radicals were synthesised. In addition, the use of these novel polymeric materials in a range of applications were studied. Those applications exploited the nature of the dormant radical groups and included controlled modifications in the polymeric structure, heterogeneous catalysis and chromatographic separations.

Due to inherent rigidity of oligoproline peptides, forcing the C- and N-terminus in proximity for cyclization can be of significant challenge. To address this issue, a cyclization condition involing the help of amphoteric aziridine aldehydes has been developed. This one step cyclization protocol generally proceeds in high yields and goes to completion in relatively short period of time. Despite their cyclic nature, the resulting molecules display spectroscopic characteristics of polyproline II helices. These macrocycles should facilitate systematic studies of various conformational states of polyproline-containing protein regions.

Due to inherent rigidity of oligoproline peptides, forcing the C- and N-terminus in proximity for cyclization can be of significant challenge. To address this issue, a cyclization condition involing the help of amphoteric aziridine aldehydes has been developed. This one step cyclization protocol generally proceeds in high yields and goes to completion in relatively short period of time. Despite their cyclic nature, the resulting molecules display spectroscopic characteristics of polyproline II helices. These macrocycles should facilitate systematic studies of various conformational states of polyproline-containing protein regions.