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

• rheology alone cannot provide. By using rheo-SANS, the structural order of the micelle solutions could be determined under flow. Worm-like micelles can align under shear, however, it was shown that under sufficiently high strain a plateau in viscosity is reached before again undergoing shear-thinning under

Understanding X-ray-induced isomerisation in photoswitchable surfactant assemblies

• Beatrice E. Jones,
• Camille Blayo,
• Jake L. Greenfield,
• Matthew J. Fuchter,
• Nathan Cowieson and
• Rachel C. Evans

Beilstein J. Org. Chem. 2024, 20, 2005–2015, doi:10.3762/bjoc.20.176

• guidelines for future X-ray experiments using photoswitchable molecules, which can aid more accurate understanding of these materials for application in solar energy storage, catalysis or controlled drug delivery. Keywords: arylazopyrazole; azobenzene; micelle; photoswitch; X-ray; Introduction The design

• ubiquitous cetyltrimethylammonium bromide (CTAB), which contain either an Azo (i.e., AzoTAB, Figure 1a) or arylazopyrazole (i.e., AAPTAB, Figure 1b) photoswitch. AzoTAB and AAPTAB were chosen as they display distinct changes in micelle morphology on irradiation with UV light to form the Z-rich PSS [4][19

• irradiation with SAXS was used to determine the mechanisms for morphology changes in AzoTAB and AAPTAB systems on Z–E isomerisation. A concentration of 50 mM in water was chosen for these experiments, as this is well above the critical micelle concentration (CMC) for both surfactants (CMC in water for (E

Supramolecular assemblies of amphiphilic donor–acceptor Stenhouse adducts as macroscopic soft scaffolds

• Ka-Lung Hung,
• Leong-Hung Cheung,
• Yikun Ren,
• Ming-Hin Chau,
• Yan-Yi Lam,
• Takashi Kajitani and
• Franco King-Chi Leung

Beilstein J. Org. Chem. 2024, 20, 1590–1603, doi:10.3762/bjoc.20.142

• micelle structures 3–4 nm in diameter (Figure 3b and Figure S8b, Supporting Information File 1). The supramolecular structure of DA11 and the supramolecular transformation were similar to those observed in DA10 [37]. This subtle increase in alkyl linker length in DA11 gave an essentially identical

Synthesis and characterization of water-soluble C₆₀–peptide conjugates

• Yue Ma,
• Lorenzo Persi and
• Yoko Yamakoshi

Beilstein J. Org. Chem. 2024, 20, 777–786, doi:10.3762/bjoc.20.71

• -soluble C60 and C70 derivatives by covalently attaching biocompatible water-soluble polymers, such as polyethylene glycol (PEG) [37][38] and PVP [39]. Although these C60– and C70–polymer conjugates revealed high water-solubility, it was found that they, especially the PEG conjugates, formed micelle-like

• photodynamic therapy photosensitizers (PDT PSs) [41] and magnetic resonance imaging contrast agents (MRI CAs) [42], which are the most relevant topics in fullerene biological studies. Aggregated fullerenes in the micelle structure may cause self-quenching of the excited state of PS fullerenes or may inhibit

Perspectives on push–pull chromophores derived from click-type [2 + 2] cycloaddition–retroelectrocyclization reactions of electron-rich alkynes and electron-deficient alkenes

• Michio Yamada

Beilstein J. Org. Chem. 2024, 20, 125–154, doi:10.3762/bjoc.20.13

• surfactant, Brij 30, was used as the reaction solvent at a concentration of 20 mM, exceeding the critical micelle concentration, 4 and 37 were obtained in a ratio of 53:47, with 64% yield. Notably, 37 exhibits instability in silica gel and polar solvents. In particular, when 37 is kept in ethyl acetate or

Facile access to pyridinium-based bent aromatic amphiphiles: nonionic surface modification of nanocarbons in water

• Lorenzo Catti,
• Shinji Aoyama and
• Michito Yoshizawa

Beilstein J. Org. Chem. 2024, 20, 32–40, doi:10.3762/bjoc.20.5

• ., graphitic carbon nitride) in the form of 10–30 nm-sized stacks is also demonstrated using the present amphiphiles. Keywords: aromatic micelle; nanocarbon; nonionic surface modification; pyridinium; water-solubilization; Introduction Nanocarbons, such as fullerenes, graphenes, and carbon nanotubes, are

• present amphiphile is originated from bent aromatic amphiphile AA [12][13], composed of two anthracene panels linked by a m-phenylene spacer with two cationic side-chains, which assembles into an aqueous ≈2 nm-sized aromatic micelle with broad host functions [14][15][16][17][18][19][20][21]. Replacement

• and structure of aromatic micelles Aromatic micelle (PA-CH3)n was facilely generated via dissolution of PA-CH3 (2.1 mg, 4.3 μmol) in water (8.6 mL). The 1H NMR spectrum of PA-CH3 in D2O showed significantly upfield-shifted signals (Δδ = −2.73 ppm for Hb) compared to the spectrum in CD3OD, in a manner

Post-functionalization of drug-loaded nanoparticles prepared by polymerization-induced self-assembly (PISA) with mitochondria targeting ligands

• Janina-Miriam Noy,
• Fan Chen and
• Martina Stenzel

Beilstein J. Org. Chem. 2021, 17, 2302–2314, doi:10.3762/bjoc.17.148

• cells. When TPP was conjugated to the pMPC PISA particles more cellular uptake as well as better spheroid penetration were observed, while TPP on PEG-based PISA had only little effect. It was hypothesized that TPP on the micelle surface may not be accessible enough to allow mitochondria targeting, but

• more structural investigations are required to elucidate this. Keywords: micelle; mitochondria; phosphorylcholine; PISA; polymerization-induced self-assembly; Introduction Targeting mitochondria is a promising strategy for the development of new anticancer drugs [1]. Among them, organoarsenical drugs

• attachment of TPP-COOH to the micelle variants resulted in an increase in hydrodynamic diameter from approximately 85 nm to 136 nm for the PEG micelles and from 75 nm to 138 nm for the zwitterionic counterparts. However, no major change in dispersities was detected and well-defined nanoparticles (PdI < 0.078

Constrained thermoresponsive polymers – new insights into fundamentals and applications

• Patricia Flemming,
• Alexander S. Münch,
• Andreas Fery and
• Petra Uhlmann

Beilstein J. Org. Chem. 2021, 17, 2123–2163, doi:10.3762/bjoc.17.138

• related concepts have been extended to polymers attached to flat or particulate surfaces as well as polymers in star or micelle constitution in the last decades. Hence, thermoresponsive polymers are still intensively investigated regarding to theory, preparation and their potential use [2][43]. However

• low viscosity, high density of polymer segments and functional groups as well as a smaller hydrodynamic radius and larger diffusion coefficient compared to linear polymer chains in solution. Amphiphilic AB-type copolymers spontaneously form micelle structures above a critical concentration by self

• interactions in contrast to star-shaped polymers. Thus, in a polar solvent, such as water, the hydrophobic block forms an anhydrous core. The hydrophilic chains stretch into the solvent in the shape of a swollen corona (Figure 5). The size, shape and dynamics of the micelle can be essentially tuned by the

¹⁹F NMR as a tool in chemical biology

• Diana Gimenez,
• Aoife Phelan,
• Cormac D. Murphy and
• Steven L. Cobb

Beilstein J. Org. Chem. 2021, 17, 293–318, doi:10.3762/bjoc.17.28

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

• is typical for wormlike micelle systems, the normalized Cole–Cole plot of G''/G''max against G'/G''max was obtained as a semicircle centered at G'/G''max = 1. The formation of network structures was also verified by polarized light microscopy. The sample was birefringent at ambient temperature and

• interaction of the alkyl chains. Keywords: dirhamnolipid ester; gemini surfactant; rheology; reverse wormlike micelle (RWLM); Introduction Surfactants have both hydrophilic and hydrophobic groups and are therefore amphiphilic molecules. Due to their unique molecular structure, surfactants are essential

• molecules are oriented with their hydrophobic groups towards the interior of the micelle and their hydrophilic groups point towards the surrounding water molecules. However, in nonpolar solvents, the structure of the micelle is similar but reversed, with the hydrophilic groups in the micelle center and the

Enzyme-instructed morphological transition of the supramolecular assemblies of branched peptides

• Dongsik Yang,
• Hongjian He and
• Bing Xu

Beilstein J. Org. Chem. 2020, 16, 2709–2718, doi:10.3762/bjoc.16.221

• the branch of the peptide, and such enzymatic proteolysis turns the micelles into nanofibers. This morphological transition (i.e., micelle to nanofiber) releases the cargos into the mitochondria of the cells [33]. These results imply that enzyme-responsive branched peptides can act as responsive

Self-assembly behaviors of perylene- and naphthalene-crown macrocycle conjugates in aqueous medium

• Xin Shen,
• Bo Li,
• Tiezheng Pan,
• Jianfeng Wu,
• Yangxin Wang,
• Jie Shang,
• Yan Ge,
• Lin Jin and
• Zhenhui Qi

Beilstein J. Org. Chem. 2019, 15, 1203–1209, doi:10.3762/bjoc.15.117

• were investigated. As shown in Figure 2a, micelle-like assemblies of 1 were observed, while, because of the higher polarity of MeCN, the aggregation of 1 through π–π stacking was considerably enhanced forming linear assemblies (Figure 2b). Interestingly, when imposed to an aqueous medium through adding

Synthesis of new p-tert-butylcalix[4]arene-based polyammonium triazolyl amphiphiles and their binding with nucleoside phosphates

• Vladimir A. Burilov,
• Guzaliya A. Fatikhova,
• Mariya N. Dokuchaeva,
• Ramil I. Nugmanov,
• Diana A. Mironova,
• Pavel V. Dorovatovskii,
• Victor N. Khrustalev,
• Svetlana E. Solovieva and
• Igor S. Antipin

Beilstein J. Org. Chem. 2018, 14, 1980–1993, doi:10.3762/bjoc.14.173

• performed for the first time. It was found that the synthesized macrocycles form stable aggregates with hydrodynamic diameters between 150–200 nm and electrokinetic potentials about +40 to +60 mV in water solutions. Critical aggregation concentration (CAC) values were measured using a micelle method with

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

• worm-like micelles, form when 1/3 ≤ p ≤ 1/2. A typical micelle acquires a hydrophobic core that is able to accommodate hydrophobic catalysts, providing thermodynamic and kinetic control over chemical reactions [31]. Moreover, carrying out reactions in such a hydrophobic core leads to a concentration

• recycling, minimizing the amount of the used organic solvent and generated waste [67]. The same group reported another interesting catalytic micelle system, which is based on PTS (polyoxyethanyl α-tocopheryl sebacate) [68]. Using PTS-based micelles, they showed the amination of allylic ethers in water

• these Pd-catalytic micelles was also achieved while catalyzing reactions involving less reactive or sterically hindered species. Handa et al. described a self-assembled TPGS-750M micelle (shown in Scheme 1), that allowed for copper-catalyzed Suzuki–Myaura coupling of aryl iodides (Scheme 2) [70]. When

Chemical systems, chemical contiguity and the emergence of life

• Terrence P. Kee and
• Pierre-Alain Monnard

Beilstein J. Org. Chem. 2017, 13, 1551–1563, doi:10.3762/bjoc.13.155

• association with the interface of chemical systems. For instance, the activity of an RNA polymerase ribozyme was improved when the various RNA compounds of the system (the ribozyme, the template/primer) were derivatized with amphiphilic moieties and co-associated within micelle structures [69]. Although no

2-Methyl-2,4-pentanediol (MPD) boosts as detergent-substitute the performance of ß-barrel hybrid catalyst for phenylacetylene polymerization

• Julia Kinzel,
• Daniel F. Sauer,
• Marco Bocola,
• Marcus Arlt,
• Tayebeh Mirzaei Garakani,
• Andreas Thiel,
• Klaus Beckerle,
• Tino Polen,
• Jun Okuda and
• Ulrich Schwaneberg

Beilstein J. Org. Chem. 2017, 13, 1498–1506, doi:10.3762/bjoc.13.148

• over micelle-forming detergents is demonstrated in the polymerization of phenylacetylene, showing a ten-fold increase in yield and increased molecular weights. Keywords: amphiphilic molecule 2-methyl-2,4-pentanediol; hybrid catalyst; phenylacetylene polymerization; refolding agents; transmembrane

• membrane of Escherichia coli (E. coli) [30]. For extraction of membrane proteins, commonly micelle-forming detergents such as sodium dodecyl sulfate (SDS), polyethylene–polyethyleneglycol (PE–PEG), sugar glycosides or polyoxyethylenes are applied [24][25][28][31][32]. SDS is an efficient detergent for

• hydrophobic micelle core. Recently, the small amphiphilic alcohol 2-methyl-2,4-pentanediol (MPD) was shown to successfully stabilize membrane proteins and enable characterization of protein modifications [33][34]. Polymerization of phenylacetylene in the presence of MPD molecules as refolding agent was

Aggregation behaviour of a single-chain, phenylene-modified bolalipid and its miscibility with classical phospholipids

• Simon Drescher,
• Vasil M. Garamus,
• Christopher J. Garvey,
• Annette Meister and
• Alfred Blume

Beilstein J. Org. Chem. 2017, 13, 995–1007, doi:10.3762/bjoc.13.99

• , the TEM image shows the presence of flexible nanofibres; no small micellar aggregates were found (B) (Figure 3). This means, the first endothermic transition of PC-C18pPhC18-PC is connected to a fibre–fibre transformation and not to a fibre–micelle transformation as found for PC-C17pPhC17-PC [35] and

• 83 Å, and Nagg is about 121 ± 5 bolalipid molecules per micelle. Modelling of the scattering curves by ellipsoids of revolution yields values for the semi axes a = b = 22 Å and c = 47 Å. The results of SANS measurements are summarized in Table 1. Mixing behaviour with saturated phosphatidylcholines

Potent triazine-based dehydrocondensing reagents substituted by an amido group

• Munetaka Kunishima,
• Daiki Kato,
• Nobu Kimura,
• Masanori Kitamura,
• Kohei Yamada and
• Kazuhito Hioki

Beilstein J. Org. Chem. 2016, 12, 1897–1903, doi:10.3762/bjoc.12.179

• ], a crown-ether-based cyclotransferase [8], membrane fusion of small unilamellar vesicles to form giant unilamellar vesicles [9], modular methods for the affinity labeling of targeting proteins [10][11][12], and reaction acceleration on micelle interfaces [13][14]. Thus, various types of molecular

Muraymycin nucleoside-peptide antibiotics: uridine-derived natural products as lead structures for the development of novel antibacterial agents

• Daniel Wiegmann,
• Stefan Koppermann,
• Marius Wirth,
• Giuliana Niro,
• Kristin Leyerer and
• Christian Ducho

Beilstein J. Org. Chem. 2016, 12, 769–795, doi:10.3762/bjoc.12.77

• to the UDP-MurNAc-pentapeptide and the FRET acceptor in a detergent or detergent/lipid micelle that also hosts the MraY protein [83]. The overexpression and purification of the transmembrane protein MraY is challenging. MraY from different bacterial strains was heterologous overexpressed in E. coli

Supramolecular polymer assembly in aqueous solution arising from cyclodextrin host–guest complexation

• Jie Wang,
• Zhiqiang Qiu,
• Yiming Wang,
• Li Li,
• Xuhong Guo,
• Duc-Truc Pham,
• Stephen F. Lincoln and
• Robert K. Prud’homme

Beilstein J. Org. Chem. 2016, 12, 50–72, doi:10.3762/bjoc.12.7

• found that the adamantyl substituents aggregate in aqueous solution to form a micelle and that subsequent addition of α-CD leads to the formation of a supramolecular hydrogel as shown in Figure 11 [88]. The driving force for gelation is a combination of the hydrophobic aggregation of the adamantyl

• adamantyl dimer f [81]. The formation of a AD-PEG micelle followed by the formation of a AD-PEG/α-CD supramolecular hydrogel in aqueous solution [88]. Interaction of PEG-b-PAA block copolymer with cis-diamminedichloroplatinum(II), cisplatin, to form a PEG-b-PAA-cisplatin micelle followed by the addition of

Aggregation behaviour of amphiphilic cyclodextrins: the nucleation stage by atomistic molecular dynamics simulations

• Giuseppina Raffaini,
• Antonino Mazzaglia and
• Fabio Ganazzoli

Beilstein J. Org. Chem. 2015, 11, 2459–2473, doi:10.3762/bjoc.11.267

• extensively studied experimentally [23][24]. The aim of the present work is to describe the first aggregation step that eventually leads to formation of a micelle or more generally of a large aggregate that may be held together through the interaction both within the cavity and, at the outer surface, by a

• water with a larger system, as described in the next section. The embryonic micelle: random aggregation of eight molecules Simulations in vacuo In order to better investigate the early stage of the nucleation of larger aggregates or possibly veritable micelles formed by the amphiphilic CDs, we first

• the alkyl chains: their cooperative effect would then favour the micelle formation vs. the isolated molecules in spite of the entropy loss entailed by the clustering process. As a final remark, we point out that with atomistic MM and MD methods we can model the first nucleation steps which may take

Hexacoordinate Ru-based olefin metathesis catalysts with pH-responsive N-heterocyclic carbene (NHC) and N-donor ligands for ROMP reactions in non-aqueous, aqueous and emulsion conditions

• Shawna L. Balof,
• K. Owen Nix,
• Matthew S. Olliff,
• Sarah E. Roessler,
• Arpita Saha,
• Kevin B. Müller,
• Ulrich Behrens,
• Edward J. Valente and
• Hans-Jörg Schanz

Beilstein J. Org. Chem. 2015, 11, 1960–1972, doi:10.3762/bjoc.11.212

• ROMP active species in the micelle may be partially or even completely deprotonated. Also, in the micelle, the H2O concentration is significantly reduced which could be another reason that a solvent-based inhibition as observed in aqueous media is minimal at best. With regard to the stability of Ru

• monomer at moderate temperatures while routinely affording near-quantitative conversions. Further investigations of the emulsion ROMP process with respect to the nature of catalytic species in the micelle and the properties of the resulting latexes and materials are currently under way. Experimental

One-pot odourless synthesis of thioesters via in situ generation of thiobenzoic acids using benzoic anhydrides and thiourea

• Mohammad Abbasi and
• Reza Khalifeh

Beilstein J. Org. Chem. 2015, 11, 1265–1273, doi:10.3762/bjoc.11.141

• aqueous Triton X-100 micelle [53]. Alternatively, the thioester could be synthesized from the reaction of the alkyl halide with the thioacid in situ generated from the reaction of thiourea and benzoyl chlorides (Scheme 1, path b). In order to explore this possibility, the alkyl halide was removed from the

N-Alkyl derivatives of diosgenyl 2-amino-2-deoxy-β-D-glucopyranoside; synthesis and antimicrobial activity

• Agata Walczewska,
• Daria Grzywacz,
• Dorota Bednarczyk,
• Małgorzata Dawgul,
• Andrzej Nowacki,
• Wojciech Kamysz,
• Beata Liberek and
• Henryk Myszka

Beilstein J. Org. Chem. 2015, 11, 869–874, doi:10.3762/bjoc.11.97

• probably due to the lower solubility of the compounds with longer N-alkyl groups or to the micelle formation. Studies on the activity of the synthesized N-alkyl derivatives of diosgenyl 2-deoxy-2-amino-β-D-glucopyranoside (8–15 and 17) against 3 strains of the human pathogenic fungi (Table 3) indicate that

Regulation of integrin and growth factor signaling in biomaterials for osteodifferentiation

• Qiang Wei,
• Theresa L. M. Pohl,
• Anja Seckinger,
• Joachim P. Spatz and
• Elisabetta A. Cavalcanti-Adam

Beilstein J. Org. Chem. 2015, 11, 773–783, doi:10.3762/bjoc.11.87

• similar size compared to individual cell receptors, thus it is possible to target receptor-driven pathways and modulate cell responses [7]. Here, the cyclic RGDfK peptides are precisely immobilized on substrates via hexagonally close-packed gold nanodot arrays prepared by block-copolymer micelle