Date of Award

Summer 8-2016

Degree Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Chemistry and Biochemistry

School

Mathematics and Natural Sciences

Committee Chair

Karl J. Wallace

Committee Chair Department

Chemistry and Biochemistry

Committee Member 2

Douglas S. Masterson

Committee Member 2 Department

Chemistry and Biochemistry

Committee Member 3

Wujian Miao

Committee Member 3 Department

Chemistry and Biochemistry

Committee Member 4

Paige Buchanan

Committee Member 4 Department

Chemistry and Biochemistry

Committee Member 5

Vijayaraghavan Rangachari

Committee Member 5 Department

Chemistry and Biochemistry

Abstract

A number of chemosensors have been designed and synthesized to target cations (Zn2+ions), neutral molecules (cathinones), charged molecules (aminoindanes), and anions. The Zn2+ ion sensor featured bistriazole designed binding unit and ferrocene signaling units. Characterization of Zn2+ ion binding was carried out with electrochemical techniques (CV and DPV), 1H-NMR, mass spectrometry, and molecular modelling. It exhibited a 1:1 binding stoichiometry with Zn2+ and had an affinity for ZnCl2 (Log K1:1 = 4.1 ± 0.02) over other Zn2+ salts.

The cathinone probe was designed to selectively bind mephedrone over common street drugs and adulterants, such as methamphetamine and acetaminophen, respectively. It featured a bisthiourea design linked by a ridged anthracene backbone. The binding occurred via hydrogen bonding and π-π interactions and was monitored via NMR, mass spectrometry, fluorescence, and molecular modelling. DFT studies found that mephedrone bound inside the molecular cleft of the dipodal bisthiourea probe, while flephedrone bound outside the binding pocket and interacted with the π system of the rigid anthracene backbone.

The aminoindane chemosensor utilized a bisaza-crown ether design to bind the protonated, primary amine functionalities on the aminoindanes through hydrogen bonds. The hydrogen bonding events were characterized using NMR, UV-Vis, and fluorescence. Unfortunately, the bisaza-crown aminoindane probe had a higher affinity for aniline-HCl (Ka = 1148 ± 1 M-1) over 2-aminoindane (Ka = 457 ± 1 M-1).

Investigation of the anion binding abilities of the bisthiourea designed mephedrone probe was carried out using NMR, fluorescence, and mass spectrometry. The thiourea moieties are known to hydrogen bond anions, so the probe was analyzed with a host of various tetrabutylammonium anion salts. It was found that the probe had an affinity for the Cl- anion (Log K2:1 > 10). Using a naphthyl moiety, rather than a benzyl one, caused the formation of an excimer upon addition of anion to a solution because the naphthyl units were brought into close proximity by the hydrogen bond coordination of the anion.

Download

Share

COinS