Year of Award
Doctor of Philosophy (PhD)
Department of Chemistry.
Leung, Ken C. F.
This thesis is divided into three sections. The first section of the thesis includes the synthesis and characterization of a catechol-containing pseudorotaxane which established a model for pseudorotaxane formation prepared through slippage method. The pseudorotaxane formation is performed in different solvents at elevated temperature in a period of time and the progress of pseudorotaxane formations were monitored with 1H NMR spectroscopy. The pseudorotaxane had been successfully synthesized in acetonitrile (MeCN) at 60 oC for 5 d with 29% yield. The second section of the thesis demonstrates the potential of the pseudorotaxane to work as a nanovalve. The opening of valve had been investigated and quantified in the presence of external stimuli such as heat, ultrasound, pH and alternating magnetic field (AMF). Furthermore, a novel core-satellite Fe3O4 nanocomposite had been prepared for AMF responsive controlled drug released system. The cytotoxicity of the core-satellite Fe3O4 nanocomposite had also been investigated and quantified in human gingival epithelial cells and human epithelial cell line, FaDu, from a squamous cell carcinoma of the hypopharynx. The core-satellite Fe3O4 nanocomposite showed non-cytotoxicity at concentration lower than 200 μg/mL and 100 μg/mL towards HGEPs and FaDu respectively. The third section of the thesis illustrates the synthesis of a novel pseudorotaxane from a signal compound which consists of a macrocycle and a coordination site through a slippage approach. The formation of mechanically interlocked molecules restricted the twisted intramolecular charge transfer (TICT) quenching process and an enhancement of fluorescence intensity was observed. With a potential to act as a fluorescent probe, the fluorescence and fluorescence-quenching nature of the pseudorotaxane had been investigated and quantified in the presence of external stimuli such as base, acid and salt. Furthermore, a series of cations and anions had been screened. The results suggested that the pseudorotaxane was a highly selective phosphate ion sensor and working with a linear operating mode.
Includes bibliographical references.
Wong, Chi Hin, "Synthesis, characterization and application of thermo-responsive  pseudorotaxane prepared by slippage approach" (2017). Open Access Theses and Dissertations. 389.
Available for download on Wednesday, October 10, 2018