Applications of microscopy and small angle scattering techniques for the characterisation of supramolecular gels

• Connor R. M. MacDonald and
• Emily R. Draper

Beilstein J. Org. Chem. 2024, 20, 2608–2634, doi:10.3762/bjoc.20.220

• supramolecular gels. Keywords: characterisation; electron microscopy; gelators; small angle scattering; supramolecular materials; Introduction Supramolecular gels are a versatile class of materials, and are of interest in many diverse applications from energy storage to cell culture [1][2]. The versatile

• , characterisation techniques, and applications of molecular gels; which still remains deeply insightful despite the rapid advancement of the field [10]. A more recent review by Yu et al. summarised a number of techniques used to characterise supramolecular materials [11]. Two of the most commonly used methods of

• be feasibly analysed [15]. A recent review by Kubota et al. summarised both the spatiotemporal advantages and disadvantages, as well as the artefacts arising from sample preparation and imaging conditions in the microscopy of molecular self-assemblies [16]. When imaging supramolecular gels, atomic

Cage-like microstructures via sequential Ugi reactions in aqueous emulsions

• Rita S. Alqubelat,
• Yaroslava A. Menzorova and
• Maxim A. Mironov

Beilstein J. Org. Chem. 2024, 20, 2078–2083, doi:10.3762/bjoc.20.179

• structures existed only within a narrow pH range: when the pH value dropped below 5.5, the chitosan easily dissolved, and when the pH value was above 7, the CMC domains swelled and lost their properties. It is known that the Ugi reaction can be successfully used to obtain cross-linked gels based on

Novel analogues of a nonnucleoside SARS-CoV-2 RdRp inhibitor as potential antivirotics

• Luca Julianna Tóth,
• Kateřina Krejčová,
• Milan Dejmek,
• Eva Žilecká,
• Blanka Klepetářová,
• Lenka Poštová Slavětínská,
• Evžen Bouřa and
• Radim Nencka

Beilstein J. Org. Chem. 2024, 20, 1029–1036, doi:10.3762/bjoc.20.91

• ) Graphical representation of the inhibitory activity of selected compounds evaluated from the gels obtained in the primer extension assay. The percentage of inhibition (against control) was plotted against the logarithm of the concentration of compounds. The results were fitted to sigmoidal dose–response

Elucidating the glycan-binding specificity and structure of Cucumis melo agglutinin, a new R-type lectin

• Jon Lundstrøm,
• Emilie Gillon,
• Valérie Chazalet,
• Nicole Kerekes,
• Antonio Di Maio,
• Ten Feizi,
• Yan Liu,
• Annabelle Varrot and
• Daniel Bojar

Beilstein J. Org. Chem. 2024, 20, 306–320, doi:10.3762/bjoc.20.31

• from the expression of CMA1 protein in CHO-S cells. Note the smeared band indicating the presence of glycosylation. (d) Recombinant expression of CMA1 in bacteria. SDS-PAGE gels of the His-tag affinity chromatography and cation exchange chromatography from the expression of CMA1 protein in E. coli BL21

Long oligodeoxynucleotides: chemical synthesis, isolation via catching-by-polymerization, verification via sequencing, and gene expression demonstration

• Yipeng Yin,
• Reed Arneson,
• Alexander Apostle,
• Adikari M. D. N. Eriyagama,
• Komal Chillar,
• Emma Burke,
• Martina Jahfetson,
• Yinan Yuan and
• Shiyue Fang

Beilstein J. Org. Chem. 2023, 19, 1957–1965, doi:10.3762/bjoc.19.146

• . The gels were stained with GelGreen®. The M13 primers covered an additional 240 bp, and therefore the PCR products containing the full-length 399 bp and 401 bp dsODNs have about 640 bp, and those without incorporated dsODNs have about 240 bp. For the case of 399 bp dsODN, colonies corresponding to

Light-responsive rotaxane-based materials: inducing motion in the solid state

• Adrian Saura-Sanmartin

Beilstein J. Org. Chem. 2023, 19, 873–880, doi:10.3762/bjoc.19.64

• supramolecular gels (Figure 2a) [52]. Upon irradiation using a UV-light-emitting diode (LED) and a visible LED as sources, the reversible cleavage of the trithiocarbonate stoppers was accomplished, thus allowing the dethreading [53] of the wheels to take place by the shuttling of the macrocycles along the thread

• (Figure 2b). Interestingly, the viscosity of the gels was progressively reduced due to the decrease of the physical entanglement of the polymeric chains via photodegradation. Thus, the viscoelasticity of the rotaxane-based gels could be fine-tuned by modifying the irradiation time. This visible-light

• photodegradation of intertwined gels could lead to advanced functional materials avoiding the UV phototoxicity for biocompatible implementations, such as protein patterning and tissue engineering. Light-responsive metal-organic rotaxane frameworks The integration of the mechanical bond into metal-organic

Preparation of β-cyclodextrin/polysaccharide foams using saponin

• Max Petitjean and
• José Ramón Isasi

Beilstein J. Org. Chem. 2023, 19, 78–88, doi:10.3762/bjoc.19.7

• carbon has been developed by Ma et al. [26], by the production of chitosan–saponin gels thanks to glutaraldehyde crosslinking. After adding potassium hydroxide, they freeze-dried the material and pyrolyzed the product. The resulting material possess a high absorption capacity of methylene blue, thanks to

Cryogels: recent applications in 3D-bioprinting, injectable cryogels, drug delivery, and wound healing

• Luke O. Jones,
• Leah Williams,
• Tasmin Boam,
• Martin Kalmet,
• Chidubem Oguike and
• Fiona L. Hatton

Beilstein J. Org. Chem. 2021, 17, 2553–2569, doi:10.3762/bjoc.17.171

• ; Introduction Gels can be defined as polymer networks that are expanded throughout their whole volume by a fluid. In the case of hydrogels, the network component is a hydrophilic polymer, and the swelling agent is water [1]. However, their lack of interconnected macropores and elasticity, required properties

• achieved in the field of injectable cryogels we can identify that the use of cryogel is not only novel but also extremely effective and easily achievable. Potential risks arise in the use of injectable gels which occur in the presence of not fully polymerised gels being injected into patients. The non

• tasks due to their adaptability and physical-chemical properties [18]. Macroporous polymeric gels with their unique heterogeneous open-porous structure open new perspectives for the development of innovative systems for biomedical and pharmaceutical applications. Cryotropic gelation is an efficient

Progress and challenges in the synthesis of sequence controlled polysaccharides

• Giulio Fittolani,
• Theodore Tyrikos-Ergas,
• Denisa Vargová,
• Manishkumar A. Chaube and
• Martina Delbianco

Beilstein J. Org. Chem. 2021, 17, 1981–2025, doi:10.3762/bjoc.17.129

• industrial applications in coating materials, cosmetics and pharmaceuticals [211]. Owing to their superior biological and mechanical properties, chitin and chitosan are used in fibers, gels, sponges, films, beads, and nanoparticles [212]. Tunable stiffness, solubility, and transparency can be obtained by

Biochemistry of fluoroprolines: the prospect of making fluorine a bioelement

• Vladimir Kubyshkin,
• Rebecca Davis and
• Nediljko Budisa

Beilstein J. Org. Chem. 2021, 17, 439–460, doi:10.3762/bjoc.17.40

Circularly polarized luminescent systems fabricated by Tröger's base derivatives through two different strategies

• Cheng Qian,
• Yuan Chen,
• Qian Zhao,
• Ming Cheng,
• Chen Lin,
• Juli Jiang and
• Leyong Wang

Beilstein J. Org. Chem. 2021, 17, 52–57, doi:10.3762/bjoc.17.6

• DGG. In the CPL-active co-gels, noncovalent weak interactions might be formed between achiral fluorophores and a chiral gelator. So, the CPL emission of co-gels could be adjusted easily by external stimuli. The ᴅ-glutamic acid gelator DGG and its enantiomer LGG possess three hydrogen-bond sites, two

• , Scheme S2) [26]. When rac-TBPP was mixed with DGG at molar ratios from 1:100 to 1:16 (rac-TBPP/DGG), transparent yellow co-gels were successfully formed by being heated to dissolve in chloroform, and then cooled to ambient temperature (Supporting Information File 1, Figure S6). Owing to the AIE effect of

• the TB unit the fluorescence intensity of these co-assembly co-gels enhanced sharply (Figure 2a). More interestingly, at the molar ratio of rac-TBPP/DGG = 1:16, the CPL spectra of the co-gel shows a negative signal, while at the molar ratio of rac-TBPP/DGG = 1:32 or higher, positive signals exhibiting

Using multiple self-sorting for switching functions in discrete multicomponent systems

• Amit Ghosh and
• Michael Schmittel

Beilstein J. Org. Chem. 2020, 16, 2831–2853, doi:10.3762/bjoc.16.233

• ‐stacking [15][16], dipole–dipole interactions [17] or hydrophobic interactions [18], have proven their significance as key players [19] in the creation of self-sorted supramolecular assemblies, such as 1D, 2D [20], and 3D architectures [21], polymers [22], gels [23], and most recently, of stand-alone

Dirhamnolipid ester – formation of reverse wormlike micelles in a binary (primerless) system

• David Liese,
• Hans Henning Wenk,
• Xin Lu,
• Jochen Kleinen and
• Gebhard Haberhauer

Beilstein J. Org. Chem. 2020, 16, 2820–2830, doi:10.3762/bjoc.16.232

• anisotropic at an elevated temperature. Differential scanning calorimetry analysis yielded a transition enthalpy of about ΔHSG/GS = ±7.2 kJ/mol. This value corresponds to a strong dispersion energy and explains the formation of the highly viscous gels by the entanglement of wormlike micelles through the

• dirhamnolipid esters, the ability to gel toluene vanishes. Rheological data Temperature sweep With this interesting observation we went on and performed rheological measurements to determine the viscoelastic properties of the dirhamnolipid ester/toluene gels. First, we performed temperature sweep measurements

pH- and concentration-dependent supramolecular self-assembly of a naturally occurring octapeptide

• Goutam Ghosh and
• Gustavo Fernández

Beilstein J. Org. Chem. 2020, 16, 2017–2025, doi:10.3762/bjoc.16.168

• -responsiveness of self-assembled peptides has been extensively exploited for potential applications, with particular focus on drug delivery systems (DDS) [40], as injectable gels for tissue engineering [41][42], and biosensing applications [43]. pH-responsive DDS can deliver the drug to a specific tissue or

Heterogeneous photocatalysis in flow chemical reactors

• Christopher G. Thomson,
• Ai-Lan Lee and
• Filipe Vilela

Beilstein J. Org. Chem. 2020, 16, 1495–1549, doi:10.3762/bjoc.16.125

The use of isoxazoline and isoxazole scaffolding in the design of novel thiourea and amide liquid-crystalline compounds

• Itamar L. Gonçalves,
• Rafaela R. da Rosa,
• Vera L. Eifler-Lima and
• Aloir A. Merlo

Beilstein J. Org. Chem. 2020, 16, 175–184, doi:10.3762/bjoc.16.20

• study of gels derived from low molecular mass gelators [15][16], and consequently the investigation of gelators of low molar mass with liquid crystal proprieties remains active [17][18]. In addition, isoxazolines and isoxazoles have been identified as promising templates in liquid crystal development

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

• - and cis-1,2-glucopyranosyl and cyclohexyl ditriazoles, synthesized by CuAAC "click" chemistry, to form gels was studied, their physical properties determined, and the self-aggregation behavior investigated by SEM, X-ray, and EDC studies. The results revealed that self-assembly was driven mainly by π–π

• stabilization of the supramolecular aggregation of bis(4-bromophenyl)triazoles. The trans or cis spatial disposition of the triazole rings is highly important for gelation, with the cis configuration having higher propensity. Keywords: circular dichroism; cis/trans configuration; gels; triazole; X-ray

• diffraction; Introduction Structures self-assembled by noncovalent interactions give rise to supramolecular architectures with specific physical and/or chemical properties. Gels are colloid systems in which the dispersed phase has combined with the dispersion medium to yield a semisolid material. Gels from

Morphology-tunable and pH-responsive supramolecular self-assemblies based on AB₂-type host–guest-conjugated amphiphilic molecules for controlled drug delivery

• Yang Bai,
• Cai-ping Liu,
• Di Chen,
• Long-hai Zhuo,
• Huai-tian Bu and
• Wei Tian

Beilstein J. Org. Chem. 2019, 15, 1925–1932, doi:10.3762/bjoc.15.188

• HGCMs containing one host and other guest moieties have been used to construct intramolecular complexes [36], cyclic oligomers [37], supramolecular polymers [23][38][39][40], gels [41][42], etc. However, AB-type HGCMs were still limited to obtain non-spherical stimuli-responsive supramolecular self

Cyclopropene derivatives of aminosugars for metabolic glycoengineering

• Jessica Hassenrück and
• Valentin Wittmann

Beilstein J. Org. Chem. 2019, 15, 584–601, doi:10.3762/bjoc.15.54

Non-metal-templated approaches to bis(borane) derivatives of macrocyclic dibridgehead diphosphines via alkene metathesis

• Tobias Fiedler,
• Michał Barbasiewicz,
• Michael Stollenz and
• John A. Gladysz

Beilstein J. Org. Chem. 2018, 14, 2354–2365, doi:10.3762/bjoc.14.211

• substoichiometric amounts of H3B·SMe2 are added to THF solutions of purified 1·BH3, gels immediately form. A ca. 0.01 M CH2Cl2 solution of 1·BH3 and a ca. 0.002 M CH2Cl2 solution of Grubbs' first generation catalyst (3 mol %) were combined at 0 °C. The mixture was warmed to room temperature, and a second charge of

A switchable [2]rotaxane with two active alkenyl groups

• Xiu-Li Zheng,
• Rong-Rong Tao,
• Rui-Rui Gu,
• Wen-Zhi Wang and
• Da-Hui Qu

Beilstein J. Org. Chem. 2018, 14, 2074–2081, doi:10.3762/bjoc.14.181

• station when the DBA site is deprotonated by external base. Besides, in the structure, one side of the chain is terminated by a bulky stopper bearing three long alkyl chains to prevent the macrocyclic moiety from slipping out the thread. Meanwhile, the long alkyl chains make it easy to form gels when the

• . The naked alkenyl groups could react with other functional groups such as alkenyl and thiol groups to prepare stimuli-responsive polymers. Besides, the introduction of long alkyl chains makes the polymers easier to form gels. This kind of functional rotaxane enriches the species of building blocks to

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

• aliphatic chain and on the other side to a glutamic acid residue. The gelator bearing the free carboxylic groups showed a lower gelation capacity than its precursor diester derivative. Some selected gels were further studied by infrared spectroscopy, rheology and electron microscopy. Critical gelation

• crystal engineering [13][14][15][16][17]. Despite their isosteric relationship with ureas, which have become key synthons in supramolecular chemistry [18][19], there are only a few reports on the formation of self-assembled supramolecular gels using squaramide derivatives [20][21][22][23]. Along this line

• , supramolecular or physical gels have received great attention during the last decade [24][25] due to their unique architectures and potential applications in many areas such as biomedicine (mainly hydrogels), health care and catalysis, among others [26][27][28][29]. In contrast to chemical gels [30], physical

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

• absorption spectroscopy, circular dichroism, scanning electron microscopy and rheological techniques. This work provides a new method for facile synthesis of chiro-optical gels. Keywords: chirality; nanostructure; organogel; photoresponse; self-assembly; Introduction Supramolecular gels [1][2] immobilized

• ], and chemosensing [13][14]. Among the supramolecular gels, the low-molecular-weight gels (LMWGs) [15][16] are those that self-assemble into gels in organic solvents with molecular weights of <2000 Da. The weak noncovalent intermolecular interactions between LMWGs make them more sensitive to external

Nanoreactors for green catalysis

• M. Teresa De Martino,
• Loai K. E. A. Abdelmohsen,
• Floris P. J. T. Rutjes and
• Jan C. M. van Hest

Beilstein J. Org. Chem. 2018, 14, 716–733, doi:10.3762/bjoc.14.61

• nanosystems suitable for many applications [113][114][115]. Catalysis in nanogels: Nanogels have intrinsic properties that make them well suited for green chemistry [116][117]. Water-compatible gels are usually based on poly(N-isopropylacrylamide) (PNIPAM), poly(N-vinylcaprolactam) (PVCL) or other water

Binding abilities of polyaminocyclodextrins: polarimetric investigations and biological assays

• Marco Russo,
• Daniele La Corte,
• Annalisa Pisciotta,
• Serena Riela,
• Rosa Alduina and
• Paolo Lo Meo

Beilstein J. Org. Chem. 2017, 13, 2751–2763, doi:10.3762/bjoc.13.271

• Tris Base, 2.75 g boric acid, 2 mL of EDTA, 0.5 M, pH 8) pH 7.5 along with the pUC19 DNA as reference. At the end of the electrophoresis, the gels were visualized under UV light using a Bio-Rad Trans illuminator. The illuminated gels were photographed by using a Polaroid camera. Heparin competitive