Date Available

12-14-2011

Year of Publication

2001

Document Type

Dissertation

College

Arts and Sciences

Department

Chemistry

First Advisor

Arthur Cammers-Goodwin

Abstract

The effect of hydrogen bonding on the conformation of organic moleculesunifies two projects in this thesis. In one project, the stability of the intramolecularhydrogen bond in derivatives of 2-guanidinobenzimidazole was studied bydynamic 1H NMR spectrometry. The impact that this intramolecular hydrogenbond had on the bond order of the neutral guanidino group and on the dynamicconformation of these aromatic structures was related to the concept of hydrogenbond-assisted resonance. In another project, an oligomer possessing repetitiveconformation and capable of much inter- and intramolecular hydrogen bondingwas designed and synthesized. The sensitivity of this oligomer to changes inanion concentration, as well as its own propensity to self-aggregate weremeasured.Hydrogen bonds found in many biological oligomers are connected thougha system of conjugated bonds. Guanidinobenzimidazole is a conjugated systemof carbon and nitrogen, connected by an intramolecular hydrogen bond. Severalderivatives of guanidinobenzimidazole were synthesized, and the effect ofseveral simple alkyl for hydrogen substitutions were studied.Guanidinobenzimidazole was used as a model to study what effect theconjugation and the intramolecular hydrogen bond have on each other.The formation of redundant low energy hydrogen bonds is universal inbiological oligomers. In DNA and RNA multiple hydrogen bonds are formed witha typical energy contribution of only 1-2 kcal/mol. Individually, these interactionsdo not give the biological oligomers their conformational stability, but togetherthey are very stable. The urea and amide based oligomers designed in the workand discussed in the thesis should form multiple hydrogen bonds withthemselves and/or with anionic guests. Chiral oligoureas were designed topossess this characteristic of cooperative conformation that so many biologicaloligomers and polymers share.

Share

COinS
 
 

To view the content in your browser, please download Adobe Reader or, alternately,
you may Download the file to your hard drive.

NOTE: The latest versions of Adobe Reader do not support viewing PDF files within Firefox on Mac OS and if you are using a modern (Intel) Mac, there is no official plugin for viewing PDF files within the browser window.