Publication Date

2015-07-30

Availability

Embargoed

Embargo Period

2017-07-29

Degree Type

Dissertation

Degree Name

Doctor of Philosophy (PHD)

Department

Chemistry (Arts and Sciences)

Date of Defense

2015-07-01

First Committee Member

Angel E. Kaifer

Second Committee Member

Françisco M. Raymo

Third Committee Member

James N. Wilson

Fourth Committee Member

Xiangyang Zhou

Abstract

Chapter 1 is an introduction about supramolecular chemistry and electrochemistry in supramolecular chemistry. First, there is a general introduction about the history of supramolecular chemistry and two important host molecules: cucurbit[n]uril and pillar[n]arene. Then a brief history of electrochemistry and several examples of electrochemistry in supramolecular chemistry are described. Chapter 2 is the electrochemical studies of viologen dications in cholate media and competition between the cholate assemblies and the cucurbit[7]uril host. The electrochemical data reveals that the binding interations between viologens and cholate assemblies are mainly hydrophobic. Competition studies with cucurbit[7]uril indicates that the rigid host molecule (cucurbit[7]uril) has better binding ability towards viologens than the dynamic host system (cholate assemblies). Chapter 3 describes the cathodic voltammetric behavior of pillar[5]quinone in dichloromethane solution. Our data show that the symmetry of the macrocycle has a pronounced effect on the electron uptake sequence. The uptake of the first five electrons follows a 2-1-2 pattern and only a total of eight electrons could be injected into the macrocycle under our experimental conditions. Chapter 4 is about the investigation of gel formation of PAMAM deidrimers with CO2. CO2 was used to crosslink adjancent dendrimers to form a three-dimensional structure, which is crucial for the formation of gel. In this investigation, we found that in H2O, no matter how big the generation is, there is no gel formed. However, in methanol, generation 0.0 has no gelation; generation 1.0 did not gel, but has some precipitates; in generation 5.0, even with a concentration of 0.005M of the dendrimer, there was gel formed with CO2 bubbled. We also converted the gel of generation 5.0 to its original PAMAM dendrimer structure by nitrogen bubbling. Chapter 5 is about the synthesis of a tetra-cholic acid cavitand. Cholic acid has a hydrophobic convex face and a hydrophilic concave face. Cavitand is one of the earliest synthetic host molecules and its has a rigid cavity. We attached four cholic acids to the upper rim of a cavitand by click chemistry, hoping that it could form an amphiphilic host molecule.

Keywords

Host-Guest Chemistry; Electrochemistry

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