Gels with exceptional thermal stability formed by bis(amino acid) oxalamide gelators and solvents of low polarity

Makarević, Janja; Jokić, Milan; Frkanec, Leo; Katalenić, Darinka; Žinić, Mladen

doi:10.1039/b206690d

Cited by 60 publications

(30 citation statements)

References 18 publications

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“…[17][18][19] It has also been demonstrated that intermolecular lipophilic interactions between alkyl substituents and intermolecular hydrogen bonding involving oxamide fragments stabilize the networks of a hydroand organogel, respectively. In addition, an irreversible photoinduced gelation system on the principle of photo- chemical isomerisation of non-gelling maleic acid amide to gelling fumaric acid amide has been prepared, [14] thereby indicating that incorporation of a photo-responsive unit in the structure of an oxamide-based gelator could lead to light-sensitive gels.…”

Section: Rational Designmentioning

confidence: 98%

Gelation Ability of Novel Oxamide‐Based Derivatives Bearing a Stilbene as a Photo‐Responsive Unit

et al. 2006

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Oxamide-based derivatives containing one or two oxamide moieties coupled to the 4-or 4,4Ј-positions of cis-and transstilbene have been synthesised. In order to modulate the solvent gelation tendencies, a series of derivatives with modified terminal functions were prepared from them. The transstilbene dioxamide-based derivatives were found to be sparingly soluble or insoluble in water and in organic solvents, whereas the trans-stilbene monooxamide-based derivatives are soluble in most organic solvents. Incorporation of a C 12 alkyl chain in the structure of the latter compounds results in a decreased solubility but in an increased gelation tendency of the substances. The ethyl ester oxamide-based derivative

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Section: Rational Designmentioning

confidence: 98%

Gelation Ability of Novel Oxamide‐Based Derivatives Bearing a Stilbene as a Photo‐Responsive Unit

et al. 2006

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“…On the other hand, some gels are thermally stable in the temperature range available for the common NMR solvents and no increase of gelator signals could be observed by heating of NMR samples. [35] NMR samples of (R)-PhG-6 and (R)-PhG-7 [D 8 ]toluene gels (c (R)-PhG-6 ϭ 0.0133 mol·dm…”

Section: Compoundmentioning

confidence: 99%

Chiral Gelators Constructed from 11‐Aminoundecanoic (AUDA), Lauric and Amino Acid Units. Synthesis, Gelling Properties and Preferred Gelation of Racemates vs. the Pure Enantiomers

et al. 2004

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A new class of efficient low molecular weight gelator molecules has been designed by combining 11‐aminoundecanoic acid (AUDA), lauric acid and aromatic and aliphatic amino acid units in the same molecule. This yields a special class of fatty acid amphiphiles with core chiral centres and hydrogen bonding sites. Some of the compounds with terminal carboxylic acid and sodium carboxylate functions exhibited ambidextrous gelation properties, being able to form gels both with highly polar solvents (water, DMSO) and also with highly lipophilic solvents, including two hydrocarbon fuels. At variance with several recent observations that the enantiomers are generally more efficient gelators than the corresponding racemates, some of the racemic gelators prepared in this work were found to be capable of gelling up to 16 times larger volumes of certain solvents than the pure enantiomers. Temperature‐dependent FTIR and 1H NMR studies of the gels formed by derivatives with terminal carboxylic acid groups and lipophilic solvents revealed that intermolecular hydrogen bonding between amidic and carboxylic acid units was involved in the self‐assembly of gel aggregates. Additional strong stabilization of the aggregates was observed in the gelators possessing terminal sodium carboxylate groups, and this was attributed to the electrostatic and ion‐dipole interactions between the sodium carboxylate groups. This additional stabilization appears to be responsible for considerably higher thermal stability of the latter gels in relation to those formed by gelators with terminal carboxylic acid groups. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)

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“…Such assemblies further organize into fibers or fiber bundles by lateral hydrogen bonding that involves both oxalyl amide and carboxyl groups. 12,29,30 Apart from efficient gelation of water, gelator 1 is capable of forming gels with the prepared colloids as well, although at a somewhat higher concentration (0.16 wt%; 4 mM). Interestingly, during gelation, colored colloidal solutions turned to colorless gels that contained visible dark clusters within their structure (Fig.…”

Section: Gelation Of Water and Colloidal Solutionsmentioning

confidence: 99%

Surface‐enhanced Raman scattering on colloid gels originated from low molecular weight gelator

Miljanić

Frkanec

Biljan

et al. 2008

J Raman Spectroscopy

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Surface-enhanced Raman scattering (SERS) on silver and gold colloid gels formed by a low molecular weight organic gelator, bis-(S-phenylalanine) oxalyl amide, was obtained. Strong Raman signals dominate in the SERS spectra of hydrogels containing silver nanoparticles prepared by citrate and borohydride reduction methods, whereas broad bands of low intensity are detected in the spectra of gold colloid gels. Resemblance between Raman spectrum of the crystalline substance and the SERS spectra of the silver nanoparticle-hydrogel composites implies the electromagnetic nature of the signal enhancement. A change in Raman intensity of the benzene and amide II bands caused by an increase in temperature and concentration indicates that the gelling molecules are strongly attached through the benzene moieties to the metal nanoparticles while participating in gel formation by intermolecular hydrogen bonding between the adjacent oxalyl amide groups. Transmission electron microscopy reveals a dense gel structure in the close vicinity of the enhancing metal particles for both silver colloid gels.

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Gels with exceptional thermal stability formed by bis(amino acid) oxalamide gelators and solvents of low polarity

Cited by 60 publications

References 18 publications

Gelation Ability of Novel Oxamide‐Based Derivatives Bearing a Stilbene as a Photo‐Responsive Unit

Gelation Ability of Novel Oxamide‐Based Derivatives Bearing a Stilbene as a Photo‐Responsive Unit

Chiral Gelators Constructed from 11‐Aminoundecanoic (AUDA), Lauric and Amino Acid Units. Synthesis, Gelling Properties and Preferred Gelation of Racemates vs. the Pure Enantiomers

Surface‐enhanced Raman scattering on colloid gels originated from low molecular weight gelator

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