Chemistry ETDs

Author

Wei Jiang

Publication Date

2-9-2010

Abstract

As one important kind of sensitive analytical technology, fluorescence method is widely applied in environmental science, materials, medicine pharmacy and nowadays much popularly in cellular biological science, which requires the development of diverse fluorescent sensors to meet various analytical and researching demands. During my Ph.D. study, my work focuses on the development of novel fluorescent sensors for the detection and specific recognition of functional and bio-interesting small molecules and metal ions, and the contents are described in this dissertation using three sections. In the first part, novel fluorescent sensors for the specific recognition of bio-toxic thiophenols have been developed based on ICT and PET mechanism separately. These sensors were designed with an 2,4-dinitrobenzenesulfonamide as the recognition moiety and consequently are able to differentiate thiophenols from bio-active aliphatic thiols such as cysteine in neutral aqueous solution due to their different pKa values. Moreover, the sensor constructed on NBD fluorophore has a long-wavelength emission (> 500 nm) and were employed as the first fluorescent sensor to detect selenocysteine, a special amine acid in body, without interference with other amino acids including similar cysteine. In the second part, we have made our efforts on the detection of explosive peroxides and discovered a highly sensitive and selective fluorescent sensor for peroxy acids. This sensor took advantage of the ring-open mechanism so as to achieve complete 'on-off' switch in the recognition process. Significant fluorescence signals were observed upon addition of peroxy acids while other peroxides and ROS couldn't make influence on the sensor. In the third part, we turned our attention to the bio-interesting metal ions. A turn-on fluorescent sensor has been developed for the detection of bio-active Zn2+ with based on PET mechanism. This sensor is highly selective for Zn2+ and showed no response to numerous metal ions such as K+, Ca2+, Mg2+, Fe3+, Cu2+, Co2+, Cd2+, etc. Moreover, we successfully designed an unprecedented chemodosimeter for the detection of highly toxic Hg2+ in the aqueous solution, which came from a unique Hg2+ facilitated desulfurization—lactonization cascade reaction by transforming a weakly fluorescent precursor to a highly fluorescent coumarin derivative.

Language

English

Keywords

fluorescence, sensor, sensitivity, selectivity

Document Type

Dissertation

Degree Name

Chemistry

Level of Degree

Doctoral

Department Name

Department of Chemistry and Chemical Biology

First Advisor

Wang, Wei

First Committee Member (Chair)

Feng, Changjian

Second Committee Member

Grey, John

Third Committee Member

Mariano, Patrick

Fourth Committee Member

Wang, Wei

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