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Self-Assembled metallomacrocycles that function as sensors and molecular devices

Zubi, Ahmed (2013) Self-Assembled metallomacrocycles that function as sensors and molecular devices. PhD thesis, University of Sheffield.

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Abstract

This thesis describes the synthesis of macrocyclic trinuclear ruthenium(II) “bowls” that incorporated 9-methyladenine, 9-benzyl-9H-purin-6-amine, 9-ethyladenine and 9-(4-methoxybenzyl)-9H-purin-6-amine as ligands with good yields and high purities. Their binding to a variety of anion guests was investigated through nuclear magnetic resonance as well as electrochemical studies. These macrocycles possess extremely interesting binding affinity:1H-NMR investigations revealed selectivity in the macrocycles-host binding, particularly with medium sized halide anions, namely chloride and bromide, being most strongly bound. Generally, electrochemistry-based titrations showed good agreement with the NMR host-guest titrations results, with potential shifts being dependent on binding affinities -although there are some specific differences in the results with fluoride and iodide. In the case of nuclear magnetic resonance we found that the fluoride ion is too small in size to be suitable for the macrocycle cavity to bind strongly, whilst in the case of electrochemistry titrations larges shifts are seen after addition of fluoride due to the high charge density of this ion. It was found that more complex oxo-anions also bound to the host and affected the RuII based oxidations. However, in general, the binding affinities for these more complex anions were lower than the highest values for halide guests. Again electrochemical potential shifts generally correlated with binding affinity. Studies also revealed that the electrochemical response to addition of anion guest was complex, as the guest induced shifts of the three RuII oxidations of the bowls were not always the same.

Item Type: Thesis (PhD)
Academic Units: The University of Sheffield > Faculty of Science (Sheffield) > Chemistry (Sheffield)
Identification Number/EthosID: uk.bl.ethos.581636
Depositing User: Mr Ahmed Zubi
Date Deposited: 18 Sep 2013 14:07
Last Modified: 03 Oct 2016 10:46
URI: http://etheses.whiterose.ac.uk/id/eprint/4390

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