Title:
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The structural analysis of porphyrin modified DNA and the construction of a molecular wire
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During this work, porphyrins have been attached onto oligonucleotides using several different methods with the aim of creating an organic electronic wire. Due to their planar, aromatic nature, porphyrins can interact with each other and transfer electrons along a self-assembled chain. Porphyrins, as a substance class have been studied extensively over the years due to their potential application in making optoelectronic devices. DNA, on the other hand has only recently been found to be an ideal supramolecular scaffold for the construction of functional molecules. Hence, combining the chemical properties of porphyrins and DNA opens the door to produce multiporphyrin arrays that have applications for example, in molecular electronic devices. Two systems have been investigated. The first, named a Zipper array, relies on π-stacking of porphyrins which are held in close proximity by the DNA scaffold. The second is designed to covalently link porphyrins in a DNA directed reaction. As well as producing a porphyrin wire, the effects of increasing modification on the circular dichroism signature and other spectroscopic techniques was investigated. This sought a greater understanding of the porphyrin-DNA structure and modified DNA in general. Circular dichroism spectroscopy was used to probe the effect porphyrin-modified nucleobases have on the DNA’s helical structure, and how porphyrins in different numbers and positions interact with each other.
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