Folding-Promoted Reactivity and Tunable Structure of Pyridine-Containing M-Phenylene Ethynylene Helical Cavitands

Heemstra, Jennifer Margaret

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Description

Title

Folding-Promoted Reactivity and Tunable Structure of Pyridine-Containing M-Phenylene Ethynylene Helical Cavitands

Author(s)

Heemstra, Jennifer Margaret

Issue Date

2005

Doctoral Committee Chair(s)

Moore, Jeffrey S.

Department of Study

Chemistry

Discipline

Chemistry

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

Ph.D.

Degree Level

Dissertation

Keyword(s)

Chemistry, Organic

Language

eng

Abstract

In one study, a hydrogen bonding interaction between adjacent monomer units is shown to stabilize the folded conformation of a PE oligomer. Subsequent studies focus on the incorporation of pyridine rings into the chain sequence. The pKa value of the pyridine nitrogen can be modulated either by changing the substituents on the pyridine ring, or in some cases, through noncovalent interactions in the folded helical structure. When the pyridine ring bears a N,N-dimethylamino substituent, the folded structure of the oligomer is shown to promote methylation of the pyridine nitrogen. The lowered energy barrier for this reaction results from binding of the methylating agent in the helical cavity of the oligomer, where it is constrained in close proximity to the pyridine nucleophile. Also, methylation of the pyridine ring is shown to stabilize the folded conformation of the oligomers through pyridinium-pi interactions. Together, these studies represent progress toward the design of functionalized PE oligomers for use as supramolecular catalysts.

Graduation Semester

2005

Type of Resource

text

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http://hdl.handle.net/2142/84187

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