Synthesis and characterization of tuneable pseudorotaxanes

The work is based on pseudorotaxane formation between different hosts and guests employing noncovalent interactions and investigating their disassembly using various external stimuli. Different tools were used to detect the pseudorataxane formation including ID and 2D NMR spectroscopy, UV-Vis spectroscopy, EPR spectroscopy, isothermal titration calorimetry, X-ray crystallography and cyclic voltammetry. A pseudorotaxane was prepared between biologically important cyclodextrin and a tetrathiafulvalene derivative which dissociated upon using a competitive guest for the cyclodextrin. Pseudorotaxane phenomena were extended to the solid-liquid interface by creating a pseudorotaxane architecture on a gold nanoparticle and in another attempt it was engineered at the periphery of a dendrimer. In both instances pseudorotaxanes were formed between 1,5-dialkoxynaphthalene and cyclobis(paraquat-p-phenylene). Atom transfer radical polymerization was used to prepare a living polymer with a naphthalene unit at one end which has the propensity to undergo pseudorotaxane formation with cyclobis(paraquat-p-phenylene). With the aim to create a multicomponent pseudorotaxane the host cyclobis(paraquat-4,4'-biphenylene) was employed which yielded a [3]pseudorotaxane with tetrathiafulvalene. A less conformationally restricted diaminopyridine based model system with different substituents was synthesised which had the ability to sustain hydrogen bonding interactions with flavin in order to understand substituent effects on flavin. electrochemical properties. An axle was synthesised for a pseudorotaxane with a flavin at one end and naphthalene unit at other end. The movements shown by pseudorotaxane association/dissociation bears similarities to molecular machine type movements in which these systems will serve as prototypes in order to create nanoscale molecular machines.EThOS - Electronic Theses Online ServiceGBUnited Kingdo