Abstract
The applications of Carboranes and Metallacarboranes for development of Ion Pair complexes and nanostructures have been described in this work.The metallacarborane anion [Co(C2B9H11)2]− has been used in conjunction with antiobiotics of the type [NR-R’H+] to form ion pair complexes which upon incorporation in the polymeric membrane of a micro-Ion Selective Electrode (ISE), can be used for the potentiometric detection of the antibiotic used in the Ion pair complex. The [Co(C2B9H11)2]− anion was also used in conjunction with Polypyrrole to form a conducting polymer layer to improve the electrical contact between the polymer membrane and the Platinum substrate. Following this methodology, micro-ISEs for detection of Irgarol, Sulfapyridine and Amphetamine in water were prepared and they showed extremely promising results. These specific compounds were chosen owing to an urgent need for inexpensive devices for their real time detection in water, as these compounds are either harmful towards living organisms (Irgarol and Sulfapyridine) or illicit drugs (Amphetamine). The micro-ISEs developed showed a lowest detection limit in the range of mmol per litre. These micro-ISEs were also extremely selective towards the target ion, even in the presence of structurally similar compounds. These micro-ISEs showed a stable pH response in the relevant pH range for use in water, whilst also giving a stable response for at least 45 days, despite repeated usage. They also showed an extremely fast response time of less than 10 seconds.
Further, carboranyl derivatives were used as capping agents for the production of CdSe Quantum Nanocrystals (QNCs). CdSe Quantum Dots, Quantum Rods, Quantum Rings and Quantum Tetrapods were produced using a simple colloidal synthesis method. The method for the production of all these QNCs was identical, except for the use of different carboranyl ligands as capping agents. A slight modification in the carboranyl derivative used as capping agent led to the formation of a different morpholigy in the quantum regime. All the QNCs produced showed intense photoluminescence, high Quantum Yield and a long, stable lifetime. All the QNCs were thoroughly characterized to check for their composition, Quantum Yield and Photoluminescent Emission intensity.
Finally, ortho-carboranethiol capped gold nanoparticles (Au NPs) were synthesied which showed the unique property of being able to transfer between aqeuous and organic phases. It was demonstrated that the phase transfer occurred upon using, divalent, trivalent and tetravalent cations. Fe3+, Ni2+, Mn2+, Ce4+ were amongst the cations that tested successfully in this phase transfer system. This further demonstrated the use of carboranyl spheres acting as vehicles for transfer of ions from aqueous to organic phase, making them ideal for ion transport in biomedical applications. It was observed that the carboranyl spheres are present on the surface of the ions to be transported, creating a kind of charged ionic pool which upon the application of a little kinetic energy, releases energy allowing the ions to transfer from one phase to another. Further, Gold coated Fe3O4 magnetic nanoparticles (MNP@Au) decorated with amine and H[Co(C2B9H11)2] (labelled as H[COSAN]) were synthesized and characterized. The incorporation of H[COSAN] in this complex allows for its use a sensing layer in a Point of Care device for early diagnosis of heart failure. The use of H[COSAN] is due to its nature as a redox specie which has a tuneable HOMO-LUMO which enhances the possibility of using it in sensing applications.
| Date of Award | 20 Sept 2019 |
|---|---|
| Original language | English |
| Supervisor | Francesc Teixidor Bombardó (Director) & Josep Ros Badosa (Tutor) |
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