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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
Doctoral Committee Chair(s):Zimmerman, Steven C.
Department / Program:Chemistry
Degree Granting Institution:University of Illinois at Urbana-Champaign
Subject(s):Chemistry, Organic
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.
Issue Date:1995
Rights Information:Copyright 1995 Baloga, Monica Helaine
Date Available in IDEALS:2011-05-07
Identifier in Online Catalog:AAI9543524
OCLC Identifier:(UMI)AAI9543524

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