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dc.contributor.authorNeal, Edward Alexander
dc.identifier.citationNeal, E.A. 2015. An Active-Template Mechanistic Approach to Homo- and Hetero-Circuit [3]Rotaxanes. Queen Mary University of Londonen_US
dc.description.abstractAlthough 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.en_US
dc.description.sponsorshipQueen Mary, University of London Graduate Teaching Studentshipen_US
dc.publisherQueen Mary University of Londonen_US
dc.titleAn Active-Template Mechanistic Approach to Homo- and Hetero-Circuit [3]Rotaxanesen_US
dc.rights.holderThe copyright of this thesis rests with the author and no quotation from it or information derived from it may be published without the prior written consent of the author

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