Author

Chi Hin Wong

Year of Award

2017

Degree Type

Thesis

Degree Name

Doctor of Philosophy (PhD)

Department

Department of Chemistry.

Principal Supervisor

Leung, Ken C. F.

Keywords

Rotaxanes; Synthesis

Language

English

Abstract

This thesis is divided into three sections. The first section of the thesis includes the synthesis and characterization of a catechol-containing [2]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 [2]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 [1]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 [1]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 [1]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 [1]pseudorotaxane was a highly selective phosphate ion sensor and working with a linear operating mode.

Comments

Principal supervisor: Dr. Leung Ken C. F. Thesis submitted to the Department of Chemistry.; Thesis (Ph.D.)--Hong Kong Baptist University, 2017.

Bibliography

Includes bibliographical references.

Available for download on Wednesday, October 10, 2018



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