University of Illinois Urbana-Champaign

Part I. Molecular tweezers: Role of preorganization and synthetic progress toward a water soluble tweezer. Part II. Progress towards an empirical approach to carbohydrate recognition

Baloga, Monica Helaine

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Description

Title
Part I. Molecular tweezers: Role of preorganization and synthetic progress toward a water soluble tweezer. Part II. Progress towards an empirical approach to carbohydrate recognition
Author(s)
Baloga, Monica Helaine
Issue Date
1995
Doctoral Committee Chair(s)
Zimmerman, Steven C.
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
  • Part I. Three molecular tweezers have been synthesized to determine the role of preorganization in the host-guest complexation of these systems. The synthesis of these tweezers was accomplished by the reaction of their respective dibromo-pyrylium salts with an absolute ethanol/aqueous ammonium hydroxide solution followed by a lithium/halogen exchange and addition of dimethoxyacridone chromophores. Tweezers 11-13 have zero, one, and two additional degrees of free rotation, respectively, which lessens the enforced syn cofacial orientation of the diacridine chromophores and the overall rigidity of the system. $\sp1$H NMR binding studies indicate an increase in the association constant (K$\sb{a}$) with the increase in rigidity. The effects of increasing rigidity are additive with $\rm\Delta\Delta G\sp\circ\sb{13\to11}=2\Delta\Delta G\sp\circ\sb{13\to12}$ = 1.8 kcal$\cdot$mol$\sp{-1}$. Thus, the enforced syn orientation of 11 provides no special benefit other than its role in preorganizing the host.
  • In addition, progress towards the synthesis of a water soluble molecular tweezer containing unsubstituted phenanthridinium chromophores is described.
  • Part II. Several classes of guest molecules present a complex three dimensional array of hydrogen bond donor and acceptor groups. In such cases a more empirical approach to host design may be most effective. We describe a rapid synthesis of bis(amidonaphthyridine) receptors by Friedlander condensations using various diketone precursors (i.e. 1,3-diacetyl benzene and 1,1$\sp\prime$-diacetyl ferrocene) and 2,6-diaminopyridine-3-carboxaldehyde (36). Complexation studies are reported including HPLC analysis of these receptors on glucose-bonded stationary phases.
Type of Resource
text
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http://hdl.handle.net/2142/21404
Copyright and License Information
Copyright 1995 Baloga, Monica Helaine

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