Influence of the gelator structure and solvent on the organisation and chirality of self-assembling fibrillar networks

Pham, Quoc Nghi; Brosse, Nicolas; Frochot, Céline; Dumas, Dominique; Hocquet, Alexandre; Jamart‐Grégoire, Brigitte

doi:10.1039/b714375c

Cited by 34 publications

(41 citation statements)

References 52 publications

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“…The organogelator was synthesized according to the procedures described in ref. (3). It was dissolved in toluene at 0.5 wt%, so that an organogel is formed at ambient temperature (measurements were carried out at 20 and 308C).…”

Section: Methodsmentioning

confidence: 99%

“…[7] can be connected to relaxation rates experimentally determined with the field-cycling instrument. Full dispersion curves which represent the variation of 3 8 R methyl 1 þ 5 8 R aromatic 1 are shown in Figure 2 for both samples (pure toluene and toluene in the gel phase). It can be noticed that the relaxometer data are consistent with those obtained from the variable field electromagnet spectrometer.…”

Section: Connection Of High Resolution Data With Relaxometer Datamentioning

confidence: 99%

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“Relaxometry” experiments and analysis of dispersion curves: An illustrative example of toluene in liquid and in organogel phases

Steiner¹,

Bouguet‐Bonnet²,

Robert³

et al. 2012

Concepts Magnetic Resonance

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At very low or low frequency, the so-called dispersion curves (longitudinal relaxation rate as a function of the measurement frequency) are obtained with a ''relaxometer,'' which is generally run according to the ''field-cycling'' technique. Because of the very poor field homogeneity, relaxation times of a single (broad) signal are measured. When going to higher fields, with standard nuclear magnetic resonance spectrometers (possibly with variable field capacities), different lines are resolved. We show how the relaxation rates pertaining to these lines can be connected to the results obtained via the relaxometer. Among other things, we demonstrate why the magnitude mode (generally used for processing the relaxometer data) must be used with caution when several lines are resolved. Actually, we could obtain accurate 1 H dispersion curves in a very broad frequency range (5 kHz-400 MHz), and we show that a decomposition into several Lorentzian curves proves to be adequate, as far as paramagnetic relaxation due to dissolved oxygen is concerned. The method will be applied i) to nondegassed liquid toluene, ii) to the same solvent involved in the formation of an organogel. In that latter case, a low frequency contribution to the dispersion curve (possibly non-Lorentzian) reveals the part of the solvent within the organogel structure. The algorithm used for analyzing these dispersion curves is described.

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Section: Methodsmentioning

confidence: 99%

Section: Connection Of High Resolution Data With Relaxometer Datamentioning

confidence: 99%

“Relaxometry” experiments and analysis of dispersion curves: An illustrative example of toluene in liquid and in organogel phases

Steiner¹,

Bouguet‐Bonnet²,

Robert³

et al. 2012

Concepts Magnetic Resonance

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“…Synthetic procedure: Compounds 1 b-f as well as 2 a and 2 b were prepared in three steps (Scheme 2) from l-amino-acid esters according to a general procedure described previously. [25] Data for compound 1 a: 8, 161.7, 161.5, 155.8, 137.9, 137.0, 135.2, 131.54, 131.47, 129.3, 128.3, 128.1, 127.6, 127.44, 127.36, 127.2, 126.4, 121.8, 65.2, 64.8, 37.8 171.4, 161.6, 161.4, 165.9, 137.0, 135.1, 131.5, 131.4, 128.3, 127.8, 127.7, 127.4, 127.2, 121.7, 65.5, 51.6, 41.1, 24.2, 23.1, 21.5 6, 161.6, 161.4, 155.6, 137.0, 135.0, 131.5, 131.4, 128.3, 127.8, 127.4, 127.1, 121.7, 65.5, 48.7, 18.6 9, 161.5, 161.4, 156.1, 137.0, 135.1, 131.4, 128.3, 127.7, 127.6, 127.4, 127.2, 121.7, 65.4, 58.6, 30.8, 19.1, 17.9 161.5, 161.4, 156.0, 137.1, 135.1, 131,5, 131.44, 131.41, 128.3, 127.7, 127.6, 127.4, 127.2, 121.7, 65.4, 57.7, 36.9, 24.2, 15.2, 11.0 1,161.6,161.5,155.8,136.9,136.1,135.1,131.5,131.4,128.2,127.6,127.4,127.2,124.0,121.7,120.8,118.5,118.2,111.3,109.9,65.2,54.1,28.2 ppm;HRMS (ESI): m/z: calcd for C 31 H 24 N 4 Na 1 O 5 : 555.1644 [M+Na] + ; found: 555.1639.…”

Section: Methodsmentioning

confidence: 99%

A Favorable, Narrow, δ_h Hansen‐Parameter Domain for Gelation of Low‐Molecular‐Weight Amino Acid Derivatives

Curcio

Allix

Pickaert

et al. 2011

Chemistry A European J

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In recent years, the design of new low-molecular-weight gelators (LMWGs) has attracted considerable attention because of the interesting supramolecular architectures as well as industrial applications. In this context, the role of the organic solvent in determining the organogelation behavior is a central question. Herein we report the results of a systematic study of the organogelation behavior of amino acid derivatives in a wide range of solvents to establish a relationship between the nature of the solvent and the formation of the gel. We highlight that the majority of the gelified solvents are aromatic, except for carbon tetrachloride and tetrachloroethylene. In addition, different parameters related to the nature of the solvent were considered and their influence on the physical properties of gelation was evaluated. The hydrogen-bonding Hansen parameter (δ(h)) allows us to draw a narrow favorable δ(h) domain for gelation in the range of 0.2-1.4 (cal cm(-3))(1/2). Furthermore, a general increase of the Hildebrand parameter (δ) leads to the formation of poor gels (small gelation numbers, GNs) in aromatic solvents. Scanning electron microscopy (SEM) revealed that the gels prepared from (l)-phenylalanine and (l)-leucine derivatives in different solvents are composed of an entangled 3D fibrillar network, the diameter of which is only slightly influenced by the nature of the solvent.

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“…Keywords: encapsulation · gels · host-guest systems · nanotubes · self-assembly Several factors, such as the solubility [14] and structure of the gelator and solvent, [21] were found to play important role in the gelation process. There is a recent report on the fabrication of a low-molecular-mass organogel system through synergistic multi-component interactions, in which the presence of five components is required to form a gel.…”

Section: Introductionmentioning

confidence: 99%

Encapsulation of Dye Molecules and Nanoparticles in Hollow Organogel Fibers of a Nonchiral Polyurethane Model Compound

Khan

Sundararajan

2010

Chemistry A European J

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We present the case of a nonchiral organogelator that forms hollow fibers and encapsulates silver nanoparticles (SNP) and a dye molecule. The biscarbamate molecule (a model compound for polyurethanes), which has two hydrogen-bonding motifs symmetrically attached to n-dodecyl side chains (C(12)), gels benzonitrile with hollow fibrillar morphology. The C(12) molecules form sheets that eventually wrap into hollow fibers to form the gel network. Herein, two-component gels were prepared with C(12) as one component and SNP, phthalocyanine (Pc), or perylene (Pe) as the other. Microscopic analysis and partial melting experiments confirmed the inclusion of the silver nanoparticles and phthalocyanine into the hollow fibers. On the other hand, Pe molecules tend to form crystals at the outer surface of the C(12) fibers, which results in a significant increase in the width of the gel fibers. This difference in the behavior of Pc and Pe molecules were accounted for by their crystal geometry and significantly different crystal growth rate compared with that of C(12) fiber formation in the gels. Pc crystallizes in a needle shape that facilitates occlusion in the gel fibers, whereas Pe forms large platelets. X-ray diffraction and spectroscopic analysis of the two-component gels along with their neat components confirmed that there was no change in the packing behavior of the Pc and Pe molecules in the gels. Therefore, these are examples of two-component physical gels in which the Pc crystals are occluded within the hollow fibers of C(12) by physical mixing of the components without the aid of any inter-molecular interactions between the different components. We have thus shown that lumen-loaded gel fibers with nanoparticles and dye molecules can be prepared by the two-component gel route, provided that the above growth rate, shape, and size conditions are satisfied.

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Influence of the gelator structure and solvent on the organisation and chirality of self-assembling fibrillar networks

Cited by 34 publications

References 52 publications

“Relaxometry” experiments and analysis of dispersion curves: An illustrative example of toluene in liquid and in organogel phases

“Relaxometry” experiments and analysis of dispersion curves: An illustrative example of toluene in liquid and in organogel phases

A Favorable, Narrow, δ_h Hansen‐Parameter Domain for Gelation of Low‐Molecular‐Weight Amino Acid Derivatives

Encapsulation of Dye Molecules and Nanoparticles in Hollow Organogel Fibers of a Nonchiral Polyurethane Model Compound

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Influence of the gelator structure and solvent on the organisation and chirality of self-assembling fibrillar networks

Cited by 34 publications

References 52 publications

“Relaxometry” experiments and analysis of dispersion curves: An illustrative example of toluene in liquid and in organogel phases

“Relaxometry” experiments and analysis of dispersion curves: An illustrative example of toluene in liquid and in organogel phases

A Favorable, Narrow, δh Hansen‐Parameter Domain for Gelation of Low‐Molecular‐Weight Amino Acid Derivatives

Encapsulation of Dye Molecules and Nanoparticles in Hollow Organogel Fibers of a Nonchiral Polyurethane Model Compound

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Product

Resources

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A Favorable, Narrow, δ_h Hansen‐Parameter Domain for Gelation of Low‐Molecular‐Weight Amino Acid Derivatives