Supramolecular self-assembly of DNA and RNA base pair functionalised porphyrins

The area of supramolecular self-assembly has received significant interest in recent years and a key area in the advancement of this field is the development of supramolecular tectons which are selective and directional in their intermolecular interactions. The four DNA nucleobases; adenine, thymine, guanine and cytosine all interact via complementary, selective and directional hydrogen bonds and have been used extensively in the design of supramolecular systems. These hydrogen bonding interactions and the effect of any substituents are studied further in both the solid and solution phases using an array of functionalised DNA nucleobases. Porphyrins substituted in the meso position by select nucleobases are synthesised and progress has been made towards the synthesis of porphyrins bearing multiple different nucleobases. This process involves either a modified Lindsey porphyrin synthesis route or a series of stoichiometric functionalisations via selective cross-coupling reactions. Finally, the self-assembly of these DNA-functionalised porphyrins is studied. Single-component supramolecular porous networks of Zn-tetra-thymineporphyrin and tetra-adenineporphyrinporphyrin are imaged and hydrogen bonding interactions are found between the molecules and modelled appropriately. These thymine and adenine-functionalised porphyrins are mixed in a 1:1 ratio and a chess-board hyrogen bonding network was formed, based on the complementary A-T hydrogen bonding interaction. This result provides promise that selective supramolecular systems can be studied with guanine and cytosine-functionalised porphryins