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Thesis (M.A.)--Eastern Illinois University, 2010. / Includes bibliographical references.

Although known to chemists for nearly a century, interlocked structures have only been synthetically accessible since the 1980s when 'passive template' methods allowed the pre-complexation of components to increase yields. 'Active template' methods, initially developed by the Leigh group in 2006, have resulted in even higher yields of rotaxanes - "interlocked structures formed of at least one macrocycle penetrated by at least one impassably-stoppered axle" - and a phenomenal surge in interest in their properties as a result of this increased availability. This first method adapted highly efficient 'click' methodology to give the Active Template Copper-Mediated Alkyne-Azide Cycloaddition reaction (AT-CuAAC) and is still the most used rotaxane-forming method today. In this work, I provide the reader with an overview of these mechanically-interlocked architectures from synthesis to application. Later work by the Goldup group showed that a smaller macrocycle could make [2]rotaxanes (one macrocycle, one axle) with complete efficiency compared to their larger forebears, while intermediate sizes gave incomplete conversion, with unused macrocycle unrecovered. In this investigation, I then identify a series of novel doubly-interlocked [3]rotaxane products from this reaction that explain the absence of unused macrocycle. I then explore the variation of conditions and show how these novel products are favoured by high temperatures and high catalyst loading in a non-coordinating solvent, whereas their yields are suppressed in low temperatures and catalyst loading in a co-ordinating solvent with base, giving up to quantitative [2]rotaxane formation. To provide a mechanistic rationale for the formation of these products I then assess the effects of stopper length, macrocycle structure and lithiation experiments on the ratio of the [2]- to [3]rotaxane. The results of the above allow me to derive a new mechanistic hypothesis when I then test in a series of experiments to form [3]rotaxanes with two rings differing in either structure, size or both. Finally, the design, synthesis and testing of a stopper developed and used by myself for the AT-CuAAC reaction is described such that where two macrocycles differ in size, the larger can only be held in a novel heterocircuit [3]rotaxane, produced in synthetically useful yields.

This thesis is divided into three sections. The first section of the thesis includes the synthesis and characterization of a catechol-containing [2]pseudorotaxane which established a model for pseudorotaxane formation prepared through slippage method. The pseudorotaxane formation is performed in different solvents at elevated temperature in a period of time and the progress of pseudorotaxane formations were monitored with 1H NMR spectroscopy. The [2]pseudorotaxane had been successfully synthesized in acetonitrile (MeCN) at 60 oC for 5 d with 29% yield. The second section of the thesis demonstrates the potential of the [1]pseudorotaxane to work as a nanovalve. The opening of valve had been investigated and quantified in the presence of external stimuli such as heat, ultrasound, pH and alternating magnetic field (AMF). Furthermore, a novel core-satellite Fe3O4 nanocomposite had been prepared for AMF responsive controlled drug released system. The cytotoxicity of the core-satellite Fe3O4 nanocomposite had also been investigated and quantified in human gingival epithelial cells and human epithelial cell line, FaDu, from a squamous cell carcinoma of the hypopharynx. The core-satellite Fe3O4 nanocomposite showed non-cytotoxicity at concentration lower than 200 μg/mL and 100 μg/mL towards HGEPs and FaDu respectively. The third section of the thesis illustrates the synthesis of a novel [1]pseudorotaxane from a signal compound which consists of a macrocycle and a coordination site through a slippage approach. The formation of mechanically interlocked molecules restricted the twisted intramolecular charge transfer (TICT) quenching process and an enhancement of fluorescence intensity was observed. With a potential to act as a fluorescent probe, the fluorescence and fluorescence-quenching nature of the [1]pseudorotaxane had been investigated and quantified in the presence of external stimuli such as base, acid and salt. Furthermore, a series of cations and anions had been screened. The results suggested that the [1]pseudorotaxane was a highly selective phosphate ion sensor and working with a linear operating mode.

Thesis (Ph. D.)--Textile and Fiber Engineering, Georgia Institute of Technology, 2006. / Srinivasarao, Mohan, Committee Chair ; Bunz, Uwe, Committee Co-Chair ; Griffin, Anselm, Committee Member ; Tolbert, Laren, Committee Member ; Park, Jung, Committee Member ; Beckham, Haskell, Committee Member. Includes bibliographical references.

Rotaxanes are a class of compounds composed of two or more mechanically interlocked molecules. Mechanically planar chiral rotaxanes are a novel class of compound in that their chirality is due to the isomerism of a mechanical bond, as opposed to the covalent bonding of the individual components. We know of no method to synthesise enantiomerically pure samples of the mechanical isomers of a mechanically planar chiral rotaxane without resorting to advanced purification techniques. The lack of ready availability of these materials has hampered the full investigation of their properties and applications. Of particular interest are their properties as chiral reaction-spaces, such as ligands, organo-catalysts, and chiral resolution agents. This thesis addresses these issues by developing a chiral-auxiliary approach toward the synthesis of mechanically planar chiral rotaxanes whereby an intermediate pair of diastereomeric rotaxanes are synthesised and separated using reliable and scalable standard laboratory techniques. Cleavage of the chiral auxiliary allows for the synthesis of enantiopure mechanically planar chiral rotaxanes. Tuning the structure of the mechanically interlocked components as well as the reaction conditions allows for control over the diastereoselectivity during the mechanical bond forming step.

本論文敘述了 III-B類輪烷樹狀物的人工合成及其表徵。透過重覆(1) 經改良的 銅(I) 催化炔烴 -疊氮偶極環加成反應 (2) 生成醯胺鍵以及最後 (3) 格拉澤 -希偶聯反應合成第一代 (G1) 及第二初代 (G2 ’)IIIB類輪烷樹狀物。 銨鹽啞及冠醚被採用來組合成分支結構的偽輪烷。 III B類輪烷樹狀物被核磁共振波譜法及電噴霧離子化法－質譜所表徵。這項研究為 III-B類輪烷樹狀物合成研究提供不可或缺的雛型 。這項研究為超分子及高化學家開拓新的領域，給予他們研究III-B類輪烷樹狀物的特性及其生醫學和電子應用機會。 / In this thesis, the syntheses and characterizations of a series of Type III-B Rotaxane Dendrimers are described. First generation (G1) and prototypical second generation (G2’) Type IIIB Rotaxane Dendrimer, which incorporate rotaxane features as the branching units, were synthesized by employing consecutive (1) modified Copper-Catalyzed Alkyne-Azide Cycloaddition (CuAAC), (2) amide formation through stopper molecule and pseudorotaxanes, and (3) GlaserHay’s acetylene homo-coupling reaction. Pseudorotaxanes with ammonium thread and crown ether macrocycle were employed. The Type III-B Rotaxane Dendrimers were characterized by nuclear magnetic resonance (NMR) spectroscopy, electrospray ionisationmass spectrometry (ESI-MS). This study provides an indispensable prototype to the synthesis of novel Type III-B Rotaxane Dendrimer. It opened up great opportunity for supramolecular and polymer chemists to further explore the properties and biomedical and electronic application of the novel dendrimers. / Detailed summary in vernacular field only. / Ho, Kwok Wai. / "October 2012." / Thesis (M.Phil.)--Chinese University of Hong Kong, 2013. / Includes bibliographical references (leaves 49-51). / Abstracts also in Chinese. / Contents --- p.i / Acknowledgments --- p.ii / Abstract --- p.iii / Abbreviations and Acronyms --- p.v / Synthetic Studies Towards Type III-B Rotaxane Dendrimer / Chapter Chapter 1 --- Introduction / Chapter 1.1 --- Classification of Rotaxane Dendrimers --- p.2 / Chapter 1.2 --- Type II-B Rotaxane Dendrimer --- p.5 / Chapter 1.3 --- Application of Copper Catalyzed Alkyne Azide Cycloaddtion(CuAAC) in Rotaxane Synthesis --- p.8 / Chapter 1.4 --- Potential Application of Type III-B Rotaxane Dendrimer --- p.12 / Chapter 1.5 --- Aim of Project --- p.14 / Chapter Chapter 2 --- Synthetic Studies Towards of Type III-B Rotaxane Dendrimer / Chapter 2.1 --- Design and Synthesis of Type III-B Rotaxane Dendrimer --- p.15 / Chapter 2.2 --- Characterization of G1 and G2’ Type III-B Rotaxane Dendron/Dendrimer --- p.27 / Chapter 2.2.1 --- ¹H NMR Spectroscopy --- p.27 / Chapter 2.2.2 --- ¹³C NMR Spectroscopy --- p.32 / Chapter 2.2.3 --- Mass Spectrometry --- p.32 / Chapter 2.3 --- Conclusion --- p.38 / Chapter Chapter 3 --- Experimental Procedures / Chapter 3.1 --- General Information --- p.39 / Chapter 3.2 --- Experimental Procedures --- p.40 / References / Appendix / List of Spectra --- p.A1

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Polyrotaxanes possess a molecular architecture resembling that of a wheel and axle: linear polymer chains are threaded by cyclic molecules with no covalent bonds linking the two species. One of two methods can be employed for the preparation of polyrotaxanes: a template method to guide threading or an in situ polymerization of monomers in the presence of cyclic molecules. The research described in this dissertation was divided into two distinct sections, which were devoted to each method of polyrotaxane preparation. The first step of synthesizing polyrotaxanes via the in situ polymerization method was to prepare a cyclic molecule. α,Ï -Dihydroxy-PDMS was cyclized and then efficiently purified by an anion-exchange resin to remove uncyclized, yet anionically charged, linear PDMS. The second part of this dissertation included examining polyrotaxanes created by the template-directed threading of α-CD onto polyoctene (PO). End-capped PO, which was unthreadable by α-CD, was synthesized from 1,9-decadiene and a monovinyl bulky compound by acyclic diene metathesis. PO and ecPO each were sonicated in aqueous solutions of α -CD; PO formed a white precipitate indicative of a rotaxanated polymer, but no precipitate formed by the addition of ecPO. These results provided evidence that PO had been included within the cavity of α-CD.