Influence of the cis/trans configuration on the supramolecular aggregation of aryltriazoles

• Sara Tejera,
• Giada Caniglia,
• Rosa L. Dorta,
• Andrea Favero,
• Javier González-Platas and
• Jesús T. Vázquez

Beilstein J. Org. Chem. 2019, 15, 2881–2888, doi:10.3762/bjoc.15.282

• thin and short fibers. The xerogel of compound 12 showed long, thin, and relatively straight fibers, with lack of torsion, as well as regularity of the network. Its cis stereoisomer 14 showed a fibrous network, but of much shorter length. However, the gel of compound 10 showed a different morphology

Synthesis and supramolecular self-assembly of glutamic acid-based squaramides

• Juan V. Alegre-Requena,
• Marleen Häring,
• Isaac G. Sonsona,
• Alex Abramov,
• Eugenia Marqués-López,
• Raquel P. Herrera and
• David Díaz Díaz

Beilstein J. Org. Chem. 2018, 14, 2065–2073, doi:10.3762/bjoc.14.180

• . In contrast, the spectrum of the xerogel, prepared by freeze-drying the corresponding organogel, revealed a red shift (lower frequency) of the above-mentioned stretching bands compared to solid 3 (C=O Δν ≈5 cm−1; N–H Δν ≈70 cm−1), which is an indication of increased hydrogen-bonding. Characterization

• acetate showed an entangled brain coral-like structure (Figure 4A), whereas the xerogel made in methanol displayed a less regular wrinkled lamellar-like structure (Figure 4B). Interestingly, the use of 1-butanol instead of methanol afforded a xerogel characterized by a poritidae-like porous structure

A self-assembled photoresponsive gel consisting of chiral nanofibers

• Lei Zou,
• Dan Han,
• Zhiyi Yuan,
• Dongdong Chang and
• Xiang Ma

Beilstein J. Org. Chem. 2018, 14, 1994–2001, doi:10.3762/bjoc.14.174

• to characterize the xerogels obtained by freeze drying. As shown in Figure 5c,d, plenty of helical nanotwists could be found in the xerogel. These fibers were intertwined together to form a 3D nanostructure. This result partially showed the gel formation pathway. Compound 3 may form dimers at the

A new class of organogelators based on triphenylmethyl derivatives of primary alcohols: hydrophobic interactions alone can mediate gelation

• Wangkhem P. Singh and
• Rajkumar S. Singh

Beilstein J. Org. Chem. 2017, 13, 138–149, doi:10.3762/bjoc.13.17

• unit which may be further exploited in the design of small molecule based gelators. Keywords: hydrophobic interactions; organogelator; SEM; triphenylmethyl group; xerogel; Introduction Small organic molecules capable of forming gels are called low molecular weight gelators (LMWGs) [1][2][3]. These

• carried out the FTIR analysis of TPM-G12 in solution (CHCl3, non-self-assembled state) and xerogel (KBr, self-assembled state) and compared their differences. Since there is no structural component capable of forming relatively strong intermolecular non-covalent interactions in TPM-G12 (e.g., hydrogen

• -plane C–H def (759 cm–1), almost identical peak values are observed in the xerogel too. The peak value for C–O str (1216 cm–1) also remains the same in both the states. So, FTIR studies strongly suggest that there is an absence of strong intermolecular non-covalent interactions in the gel state. XRD

Star-shaped tetrathiafulvalene oligomers towards the construction of conducting supramolecular assembly

• Masahiko Iyoda and
• Masashi Hasegawa

Beilstein J. Org. Chem. 2015, 11, 1596–1613, doi:10.3762/bjoc.11.175

• self-aggregated in chloroform–dioxane to form a gel. TEM images of the xerogel exhibited helical molecular tapes nanometer wide and micrometer long. A cyclic voltammetry (CV) study on 2b showed the redox properties expected for Pc and TTF, and doping of 2b in CH2Cl2 with I2 produced a radical cation

Synthesis of photoresponsive cholesterol-based azobenzene organogels: dependence on different spacer lengths

• Yuchun Ren,
• Bin Wang and
• Xiuqing Zhang

Beilstein J. Org. Chem. 2015, 11, 1089–1095, doi:10.3762/bjoc.11.122

• . Obviously, the gel from ethanol mainly shows a similar flower-like morphology. When we focused on the isopropanol xerogel, we could see that there are many regularly three-dimensional network structures. In 1-butanol, the organogelator molecules in the gel phase were self-assembled into tightly staked rods

• were conducted and the results were displayed in Figure 6. The pattern of the xerogel obtained from the 1-butanol gel exhibited five peaks at 12.84, 15.38, 17.22, and 20.44°, corresponding to d-spacing of 6.90, 5.80, 5.14, 4.30, and 3.70 nm, respectively. The d-spacing almost in ratio of 7:6:5:4, may

Improving the reactivity of phenylacetylene macrocycles toward topochemical polymerization by side chains modification

• Simon Rondeau-Gagné,
• Jules Roméo Néabo,
• Maxime Daigle,
• Katy Cantin and
• Jean-François Morin

Beilstein J. Org. Chem. 2014, 10, 1613–1619, doi:10.3762/bjoc.10.167

• the xerogel state to form polydiacetylenes (PDAs), leading to a significant enhancement of the polymerization yields. The organogels and the PDAs were characterized using Raman spectroscopy, X-ray diffraction (XRD) and scanning electron microscopy (SEM). Keywords: carbon nanomaterials; organogels

• present any gelation properties. For SEM analysis, a gel sample was allowed to dry at room temperature on a metallic substrate to form a xerogel. Then, gold was sputtered on the sample prior to imaging. SEM images of PAM2 are shown in Figure 2. As previously observed with PAM1 and other phenylacetylene

• organization. Despite this unexpected finding, irradiation of a xerogel sample of PAM2 in cyclohexane (10 mg/mL) was performed for 24 h under UV light (254 nm). The resulting blue material was purified using size-exclusion chromatography (SEC) (Bio-Beads SX-1) to remove all traces of the starting macrocycle

Charge-transfer interaction mediated organogels from 18β-glycyrrhetinic acid appended pyrene

• Jun Hu,
• Jindan Wu,
• Qian Wang and
• Yong Ju

Beilstein J. Org. Chem. 2013, 9, 2877–2885, doi:10.3762/bjoc.9.324

• measure these kinds of networks or gelator aggregates. As shown in Figure 4, the CT xerogel based on GA-pyrene (3) and TNF (4) in different solvents could self-assemble into micro-scale fibrous structures with regular diameters of ca. 0.5–3 μm, and by entanglement of such fibers, a closely packed 3D

Self-assembly of 2,3-dihydroxycholestane steroids into supramolecular organogels as a soft template for the in-situ generation of silicate nanomaterials

• Valeria C. Edelsztein,
• Andrea S. Mac Cormack,
• Matías Ciarlantini and
• Pablo H. Di Chenna

Beilstein J. Org. Chem. 2013, 9, 1826–1836, doi:10.3762/bjoc.9.213

• LMOG 1 in the liquid-like solution phase trapped within the SAFIN (see Supporting Information File 1 for IR spectra) [17]. The microscopic morphology of the xerogel of 1 from DCM, n-hexane and dioxane was analyzed by SEM. The images showed an entangled fibrillar network for all solvents. Particularly

• the images of the dichloromethane xerogel (Figure 4a and Figure 4b) showed left handed helical fibers with a fiber width ranging from 20 to 75 nm, and a helicoidal period of about 750 nm. The helical shape is clearly observed in the isolated fibers (Figure 4a), but these are difficult to find in the

• bulk due to the collapsed fibrillar network. For n-hexane and dioxane simple straight entangled fibers were observed with a minimum width of 20 nm. In all cases fibers with lengths of up to several micrometers were clearly visible. SEM images of the xerogel from dioxane showed a tighter SAFIN compared

C–C Bond formation catalyzed by natural gelatin and collagen proteins

• Dennis Kühbeck,
• Basab Bijayi Dhar,
• Eva-Maria Schön,
• Carlos Cativiela,
• Vicente Gotor-Fernández and
• David Díaz Díaz

Beilstein J. Org. Chem. 2013, 9, 1111–1118, doi:10.3762/bjoc.9.123

• scanning electron microscope (FESEM, resolution 0.8 nm) equipped with a digital camera and operating at 5 kV (accelerating voltage) and 10 μA (emission current). Xerogel samples of the corresponding hydrogels were prepared by the freeze-drying (FD) method [32]. The resulting material was placed on top of a

• = initial concentration at t = zero time. Selected FESEM images of different catalysts used for comparative kinetics: (a) powdered BSA; (b) powdered collagen; (c) powdered PSTA gelatin; (d) powdered chitosan; (e) xerogel prepared by freeze-drying the hydrogel made of PSTA gelatin; (f) commercial powdered

A peptidic hydrogel that may behave as a “Trojan Horse”

• Nicola Castellucci,
• Giorgio Sartor,
• Natalia Calonghi,
• Carola Parolin,
• Giuseppe Falini and
• Claudia Tomasini

Beilstein J. Org. Chem. 2013, 9, 417–424, doi:10.3762/bjoc.9.44

• the xerogel, making a complex network. The gelator is derived from α-amino acids (Thr, Phe) and a fatty acid (azelaic acid) and is biocompatible: it was dosed to IGROV-1 cells, which internalized it, without significantly affecting the cell proliferation. To check the internalization process by

• as gelator, doped by a small amount of the dansyl-containing compounds B, C and D. These all readily form fluorescent hydrogels, which may be used to evaluate the cellular uptake of A. Before evaluating the cellular uptake of the hydrogels, the structure of 1 (hydrogel), and its corresponding xerogel

• , failed to show the low-angle diffraction effects. The freeze drying of hydrogel 1 produced the xerogel 1, which appeared as a fractured film (Figure 3a inset). In this film a fibrous structure is observed (Figure 3a). The fibers appear locally organized in bundles, which are randomly oriented. The powder

Amphiphilic dendritic peptides: Synthesis and behavior as an organogelator and liquid crystal

• Baoxiang Gao,
• Hongxia Li,
• Defang Xia,
• Sufang Sun and
• Xinwu Ba

Beilstein J. Org. Chem. 2011, 7, 198–203, doi:10.3762/bjoc.7.26

• . Compound G3 gelled in n-hexane, toluene, 1,4-dioxane, and ethanol but was soluble in dichloromethane. The microscopic structure of the gel was investigated by field-emission SEM (FE-SEM). Figure 1 shows representative FE-SEM images of the xerogel of G3 formed in n-hexane. These images clearly show that

Differences between β-Ala and Gly-Gly in the design of amino acids-based hydrogels

• Andreea Pasc,
• Firmin Obounou Akong,
• Sedat Cosgun and
• Christine Gérardin

Beilstein J. Org. Chem. 2010, 6, 973–977, doi:10.3762/bjoc.6.109

• in the free powder. The free individual IR frequencies of amide I-III were identified from the corresponding IR spectra of H2N-EO2-C14 (amide I, 1633 cm−1), His-EO2-C14 (amide II, 1643 cm−1) and β-Ala-His-EO2-C14 (amide III, 1681 cm−1), respectively. In the xerogel, only one absorption band was

• range of chiral molecules. Molecular structures of β-Ala-His-EO2-C14 (a) and Gly-Gly-His-EO2-C14 (b). ATR spectra of β-Ala-His-EO2-C14 in xerogel and D2O hydrogel, respectively. SAXS profile of concentrated gel of β-Ala-His-EO2-C14 at different temperatures (where S = 2π/q and q is the scattering vector

Towards racemizable chiral organogelators

• Jian Bin Lin,
• Debarshi Dasgupta,
• Seda Cantekin and
• Albertus P. H. J. Schenning

Beilstein J. Org. Chem. 2010, 6, 960–965, doi:10.3762/bjoc.6.107

• NMR spectra of R-3 in chloroform (CDCl3). The red colours indicate the hydrogen resonances of the amide unit. a) R-3 gel in octane (5 mM); b) octane solution containing a mixture of R-3 (2.5 mM) and S-3 (2.5 mM) after cooling from 80 °C to room temperature; c) TEM image of the xerogel of R-3 in octane

Oxalyl retro-peptide gelators. Synthesis, gelation properties and stereochemical effects

• Janja Makarević,
• Milan Jokić,
• Leo Frkanec,
• Vesna Čaplar,
• Nataša Šijaković Vujičić and
• Mladen Žinić

Beilstein J. Org. Chem. 2010, 6, 945–959, doi:10.3762/bjoc.6.106

• chirality as observed for some other gels of the chiral gelators. XRPD, molecular modeling and packing model The X-ray powder diffraction (XRPD) pattern of (S,S)-1b xerogel showed strong peaks corresponding to periodic distance d of 16.1 and 13.4 Å and a weaker peaks corresponding to d’s of 15.1 and 8.6 Å

• (Figure 9b). For the (S,R)-1b xerogel, strong peaks corresponding to d’s of 14.9 and 13.4 Å and smaller peaks to d’s of 13.98, 8.6 and 7.5 Å could be observed (Figure 9a). Molecular modeling of (S,R)-1b and (S,S)-1b yields low energy extended conformations with lengths of 15.1 and 15.9 Å, respectively

• water/DMSO gel assemblies was not possible due to solvent unsuitability. Nevertheless, the FTIR spectrum of the (S,R)-1b xerogel prepared from its water/DMSO gel was found to differ from that of the crystalline sample; the positions of NH stretching, carboxylic acid and amide I carbonyl stretching, and

Pyridinium based amphiphilic hydrogelators as potential antibacterial agents

• Sayanti Brahmachari,
• Sisir Debnath,
• Sounak Dutta and
• Prasanta Kumar Das

Beilstein J. Org. Chem. 2010, 6, 859–868, doi:10.3762/bjoc.6.101

• architecture of 2 at the aggregated state was further confirmed by Atomic Force Microscopic (AFM) images. Two and three dimensional AFM images of xerogel 2 (Figure 3c, d) showed the involvement of fibrillar networks in self-assembled hydrogelation. The dimension of the fibril network observed in the AFM image

• which is in accord with the absence of any kind of intermolecular interaction in the non-gelated state of the amphiphile. To investigate the molecular packing and orientation of the gelator molecules in the supramolecular self-assembled state, the xerogel of 2 was examined by X-ray diffraction (XRD). A

• (λ = 0.15406 nm) with a voltage and current of 40 kV and 30 mA, respectively. The gel was mounted on a glass slide and dried under vaccum. The xerogel was scanned from 2Θ = 1–40°. Microorganisms and culture conditions The in vitro antimicrobial activity of the cationic amphiphiles was investigated

Chiral gels derived from secondary ammonium salts of (1R,3S)-(+)-camphoric acid

• Tapas Kumar Adalder,
• N. N. Adarsh,
• Ravish Sankolli and
• Parthasarathi Dastidar

Beilstein J. Org. Chem. 2010, 6, 848–858, doi:10.3762/bjoc.6.100

• 1,2-dichlorobenzene xerogels of DBAMC 6, whereas relatively short plate like morphology was observed in the nitrobenzene xerogel of DBUAMC 3. Understandably, the solvent molecules are immobilized in these networks to form gel. To prove structure-property correlation in these gelators, we tried to

• interactions. To see if these crystal structures of 3 and 6 (as discussed above) truly represent the bulk solid as well as the xerogels, we undertook detailed PXRD studies. The comparison plot involving simulated, bulk and xerogel PXRDs for both the salts do not match which indicate the presence of other

• -ray diffraction techniques was inconclusive as the PXRD patterns of the simulated, bulk and xerogel do not match in both the gelators. Moreover, salt 1 which displayed 1-D SAD synthon failed to gel any of the solvents studied herein indicating that many factors that might be crucial for gelation such