Hydrogen Bonding Control of Molecular Self-Assembly: Aggregation Behavior of Acylaminopyridine–Carboxylic Acid Derivatives in Solution and the Solid State

Zafar, Abdullah; Geib, Steven J.; Hamuro, Yoshitomo; Carr, Andrew; Hamilton, Andrew D.

doi:10.1016/s0040-4020(00)00733-x

Cited by 52 publications

(44 citation statements)

References 15 publications

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“…The commercially available 6-methylpyridin-2-ylamine (14) was acylated with acetic anhydride in toluene by a literature procedure. [9] The methyl group of the pyridinium salt 15 was oxidized with KMnO 4 to provide the pyridinecarboxylic acid 16, [9,10] which after activation with PyBOP was coupled with the mono-Boc-protected guanidine 9 to yield the Boc-protected receptor 17. The last step was the deprotection of 17 with TFA and the crystallization of the picrate salt of the receptor 3 from methanol.…”

Section: Resultsmentioning

confidence: 99%

Amino Acid Binding by 2‐(Guanidiniocarbonyl)pyridines in Aqueous Solvents: A Comparative Binding Study Correlating Complex Stability with Stereoelectronic Factors

Schmuck

Machon

2005

Chemistry A European J

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A series of guanidiniocarbonylpyridine receptors has been synthesized, and these compounds bind amino acids (carboxylate forms) in aqueous DMSO with association constants ranging from K = 30 to 460 M(-1) as determined by NMR titration experiments. The differences in the complex stabilities can be correlated with steric and electrostatic effects with the aid of calculated complex structures. For example, the electrostatic repulsion between the pyridine nitrogen lone pair and the bound carboxylate makes anion binding less efficient than with the analogous pyrrole receptors previously introduced by us for carboxylate binding in water. Furthermore, steric interactions between the receptor side chain as in 2 b and the bound substrate also disfavor complexation.

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Section: Resultsmentioning

confidence: 99%

Amino Acid Binding by 2‐(Guanidiniocarbonyl)pyridines in Aqueous Solvents: A Comparative Binding Study Correlating Complex Stability with Stereoelectronic Factors

Schmuck

Machon

2005

Chemistry A European J

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“…[35] In the case of the pyridinedicarboxamide oligomers, we suggested that chiral induction may occur by well-characterized hydrogen bonding between carboxylic acids and acylaminopyridines. [36] Binding to diacylaminopyridine units residing at the center of helical pyridinedicarboxamide oligomers should be disfavored because the amidic protons of these units are already hydrogen bonded to the pyridine's nitrogen atoms of the adjacent pyridinecarboxamide units. Moreover, these units are buried in the hollow of the helix and so should not be available in any great number for hydrogen bonding unless partial unfolding occurs.…”

Section: Intermolecular Chiral Inductionmentioning

confidence: 99%

Intramolecular Versus Intermolecular Induction of Helical Handedness in Pyridinedicarboxamide Oligomers

2005

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A new convergent synthetic scheme has been developed to prepare oligoamides of 2,6-diaminopyridine and 4-decyloxy-2,6-pyridinedicarboxylic acid. These compounds adopt stable single helical conformations in solution. NMR and circular dichroism studies show that intramolecular and intermolecular chiral induction of handedness in these helices is possible. Intramolecular induction is effected by attaching a single chiral group to the end of an oligomer. Intermolecular

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“…[1,2] It is known to form inclusion complexes with n-alkanes (! 7 carbon atoms) [3][4][5][6] and some functionalized longchain molecules.…”

Section: Introductionmentioning

confidence: 99%

Urea and Thiourea Derivatives as Low Molecular‐Mass Organogelators

George

Tan

John

et al. 2005

Chemistry A European J

164

108

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The properties of a series of organogels consisting of a urea or thiourea derivative with one or two n-alkyl substitutuents at the nitrogen atoms (a low molecular-mass organogelator (LMOG)) and an organic liquid are described. They include N,N'-dimethylurea, the LMOG of lowest molecular mass (M(W) 88) we are aware of. The efficiencies of the LMOGs, based the diversity of liquids gelated, the minimum amount required for gelation of a liquid at room temperature, and the temporal and thermal stabilities of the gels formed, have been investigated as a function of the number, length, and substitution pattern of their n-alkyl chains. The gels are thermally reversible and require generally very low concentrations (<2 wt %) of an LMOG. Some of the LMOGs with shorter chains are more efficient than their longer chained analogues. The structural and thermodynamic properties of the gels have been examined by IR, DSC, and X-ray diffraction techniques. Polarizing optical microscopic analyses of the gels show that the nature of gelator aggregates depends mainly on the alkyl chain length. Changes in the aggregation ability have been examined systematically by perturbing the molecular structure.

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Hydrogen Bonding Control of Molecular Self-Assembly: Aggregation Behavior of Acylaminopyridine–Carboxylic Acid Derivatives in Solution and the Solid State

Cited by 52 publications

References 15 publications

Amino Acid Binding by 2‐(Guanidiniocarbonyl)pyridines in Aqueous Solvents: A Comparative Binding Study Correlating Complex Stability with Stereoelectronic Factors

Amino Acid Binding by 2‐(Guanidiniocarbonyl)pyridines in Aqueous Solvents: A Comparative Binding Study Correlating Complex Stability with Stereoelectronic Factors

Intramolecular Versus Intermolecular Induction of Helical Handedness in Pyridinedicarboxamide Oligomers

Urea and Thiourea Derivatives as Low Molecular‐Mass Organogelators

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