dc.contributor.author | Neal, Edward Alexander | |
dc.date.accessioned | 2016-09-07T11:38:56Z | |
dc.date.available | 2016-09-07T11:38:56Z | |
dc.date.issued | 2015-07-22 | |
dc.date.submitted | 2016-09-07T12:31:17.935Z | |
dc.identifier.citation | Neal, E.A. 2015. An Active-Template Mechanistic Approach to Homo- and Hetero-Circuit [3]Rotaxanes. Queen Mary University of London | en_US |
dc.identifier.uri | http://qmro.qmul.ac.uk/xmlui/handle/123456789/15016 | |
dc.description.abstract | 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. | en_US |
dc.description.sponsorship | Queen Mary, University of London Graduate Teaching Studentship | en_US |
dc.language.iso | en | en_US |
dc.publisher | Queen Mary University of London | en_US |
dc.subject | rotaxanes | en_US |
dc.title | An Active-Template Mechanistic Approach to Homo- and Hetero-Circuit [3]Rotaxanes | en_US |
dc.type | Thesis | en_US |
dc.rights.holder | The 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 | |