Self assembly of hybrid nanostructures encompassing inorganic, organic and biological applications.
MSc(R) thesis, University of Glasgow.
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The work presented in this thesis will highlight the modification of inorganic and biological materials with organic tethers; the subsequent characterisation of these compounds and the surface studies used to investigate them further. On moving from materials science to cell biology, a variety of techniques are used to demonstrate the chemical modifications and the role the surface has to play in not only visualising the effect of the modification but the surface itself mediating reactions.
Described within is the further investigation of Mn Anderson based polyoxometalate clusters .This report documents the grafting of C-16, C-18 alkyl chains and pyrene to hydrophilic Mn Anderson clusters. Solid state studies using scanning electron microscopy and transmission electron microscopy demonstrates the effect of cation exchange from tetrabutyl ammonium (TBA) to dimethyldioctadecyl ammonium (DMDOA) resulting in new POM assemblies. For the C-18 and to some extent the C-16 grafted clusters, uniform, highly ordered assemblies are reported in contrast to the “sea urchin” like structures observed on cation and solvent exchange. The generation of surfactant encapsulated clusters in conjunction with surface grafted clusters has been achieved.
For the first time these organically tethered POM‟s have been patterned successfully onto self assembled monolayers (SAMs) using microcontact printing. In addition to this, studies involving human fibroblast cells (hTERT-BJI) are reported. Cells have been found to attach and spread on monolayers terminated in pyrene terminated POM. It has been observed that POMs play a crucial role in the adhesion of cells to surfaces.
Solid state techniques scanning electron microscopy (SEM) and atomic force microscopy (AFM) are used in the investigation of not only inorganic compounds but the post translational modification of proteins. Highlighting the importance of these techniques in the further understanding or reactions and the effects the reactions have on the molecules
Further the investigation of polyoxometalates herein the development of molybdenum (VI) oxide polyoxometalate cluster, β-[Mo18O54(SO3)2]4-, that canundergo a reversible conversion between two electronic states, upon thermal activation is described. Experiments have uncovered the fact that the two embedded redox agents can be thermally activated and ejected from the sulfite anions and delocalised over the metal oxide cluster. The role of the surface in such a reaction is described detailing its importance in the reaction from a fully oxidised state to a two electron reduced state. This work demonstrates the use of a POM as a potential starting point to create a single molecule device at the nanoscale.
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