Electron-beam-promoted fullerene dimerization in nanotubes: insights from DFT computations

• Laura Abella,
• Gerard Novell-Leruth,
• Josep M. Ricart,
• Josep M. Poblet and
• Antonio Rodríguez-Fortea

Beilstein J. Org. Chem. 2024, 20, 92–100, doi:10.3762/bjoc.20.10

• electron microscopy (TEM) is a technique that has been used for a long time to provide images of molecules, but also to monitor the reactions triggered by the energy transfer of the electron beam to the atoms that build the molecules. In particular, the advances in TEM as well as in methods to anchor

• molecules on surfaces like graphene or carbon nanotubes have allowed the scientific community to visualize at atomic resolution the structural changes of molecules in situ by single-molecule atomic-resolution real-time TEM imaging (SMART-TEM) [1][2][3][4][5]. Since the initial discovery [2], many movies

• nanotubular-shaped fullerene inside the peapod. Kinetic analysis with the variable-temperature (VT) SMART-TEM method for the aforementioned C60 dimerization has also been reported by these authors [9]. They concluded that the SWCNT, which accumulates energy by the interaction with the electron beam, activates

Preparing a liquid crystalline dispersion of carbon nanotubes with high aspect ratio

• Keiko Kojima,
• Nodoka Kosugi,
• Hirokuni Jintoku,
• Kazufumi Kobashi and
• Toshiya Okazaki

Beilstein J. Org. Chem. 2024, 20, 52–58, doi:10.3762/bjoc.20.7

• was larger than the value reported in previous research (L/D = 1088) [23]. Based on the transmission electron microscope (TEM) images, the average diameter of DWCNTs was ≈1.8 nm (Supporting Information File 1, Figure S1a). Since the observed DWCNT diameter based on the SEM images is ≈2.1 nm, the

pH-Responsive fluorescent supramolecular nanoparticles based on tetraphenylethylene-labelled chitosan and a six-fold carboxylated tribenzotriquinacene

• Nan Yang,
• Yi-Yan Zhu,
• Wei-Xiu Lin,
• Yi-Long Lu and
• Wen-Rong Xu

Beilstein J. Org. Chem. 2023, 19, 635–645, doi:10.3762/bjoc.19.45

• of a large number of nanoparticles. Conversely, solutions with concentrations below the CAC values did not show an apparent Tyndall effect (Figure S3 in Supporting Information File 1), which provides further support for the accuracy of the CAC values. Transmission electron microscopy (TEM) was used

• were characterized by TEM and dynamic laser scattering (DLS). TBTQ-C6/CS-TPE containing either of the different TPE-loadings all formed uniform spherical nanoparticles with average diameters of 152 nm, 158 nm and 199 nm, respectively, as determined by TEM measurements (Figure 6a and Figures S5a and S6a

• larger than those measured by TEM. This is because TEM probes samples in the dry state, while DLS examines samples in the solvated state, where the solvent molecules are associated with the nanoparticles. The zeta potentials of these three TBTQ-C6/CS-TPE nanoparticles were further measured to determine

C3-Alkylation of furfural derivatives by continuous flow homogeneous catalysis

• Grédy Kiala Kinkutu,
• Catherine Louis,
• Myriam Roy,
• Juliette Blanchard and
• Julie Oble

Beilstein J. Org. Chem. 2023, 19, 582–592, doi:10.3762/bjoc.19.43

• Supporting Information File 1, p. S20), meaning that the ruthenium trimer was no longer present. The TEM analysis of the recovered solid phase (Scheme 5B) showed the formation of large aggregates with high electron density. Moreover, ruthenium was detected by XPS analysis (Scheme 5B); the binding energy of

• reaction with formation of ruthenium aggregates and mononuclear Ru(0) catalyst. A) Isolation test of a reaction intermediate; B) XPS and TEM (in ethanol) of the recovered solid phase: showing the presence of Ru aggregates. Ruthenium aggregate-catalyzed alkylation reaction. Scope of continuous flow furfural

First series of N-alkylamino peptoid homooligomers: solution phase synthesis and conformational investigation

• Maxime Pypec,
• Laurent Jouffret,
• Claude Taillefumier and
• Olivier Roy

Beilstein J. Org. Chem. 2022, 18, 845–854, doi:10.3762/bjoc.18.85

• length, corresponding to the amide I C=O stretching of the N-(methylamino)amides functions. Preliminary transmission electron microscopy (TEM) analysis of dimer 2 seems to suggest ordered self-assembled multilayered structures (Figure S5 in Supporting Information File 1). This observation now needs to be

• folding and intermolecular association properties. The NMR study shows that this peptoid family has a strong propensity to form intermolecular assemblies in solution, whatever the nature of the solvent. TEM images of dimer 2 in water may suggest the formation of multilayered assemblies that deserve to be

• Information Supporting Information File 67: Experimental procedures, HPLC analytical data, NMR spectra and variable concentration study, infrared spectra, full X-ray data for 2, computation data, and additional TEM images for compound 2. Supporting Information File 68: Crystallographic information file (CIF

Tetraphenylethylene-embedded pillar[5]arene-based orthogonal self-assembly for efficient photocatalysis in water

• Zhihang Bai,
• Krishnasamy Velmurugan,
• Xueqi Tian,
• Minzan Zuo,
• Kaiya Wang and
• Xiao-Yu Hu

Beilstein J. Org. Chem. 2022, 18, 429–437, doi:10.3762/bjoc.18.45

• binding interaction between m-TPEWP5 and G is strong enough to form a stable complex in an aqueous solution. The morphology of the supramolecular m-TPEWP5G and m-TPEWP5G-EsY systems was monitored by using transmission electron microscopy (TEM). As shown in Figure 3, m-TPEWP5G self-assembled to form a worm

• showing a 1:1 binding stoichiometry between m-TPEWP5 and G by plotting the emission intensity differences at 470 nm against the mole fraction of G in an aqueous solution (λex = 320 nm). TEM images of (a) m-TPEWP5G; (b) m-TPEWP5G-EsY. [m-TPEWP5] = 1 × 10−4 M, [G] = 1 × 10−4 M, [EsY] = 1 × 10−4 M. (a

Recent developments and trends in the iron- and cobalt-catalyzed Sonogashira reactions

• Surendran Amrutha,
• Sankaran Radhika and
• Gopinathan Anilkumar

Beilstein J. Org. Chem. 2022, 18, 262–285, doi:10.3762/bjoc.18.31

• phenylacetylene in the presence of a series of PdCo bimetallic nanoparticles with different compositions on graphite sheets as highly active catalysts (Scheme 27) [40]. The catalyst was prepared by a chemical reduction method and characterized by various techniques like Raman, XRD, TEM, and XPS. The Pd/Co(1:1)NPs

Synthesis and bioactivity of pyrrole-conjugated phosphopeptides

• Qiuxin Zhang,
• Weiyi Tan and
• Bing Xu

Beilstein J. Org. Chem. 2022, 18, 159–166, doi:10.3762/bjoc.18.17

• derivatives. Enzymatic conversion To further investigate the reason for the different activities in cell assays among the three compounds, 1, 4a and 6b, we employed transmission electron microscopy (TEM) to study the morphologies of the assemblies of these compounds before and after enzymatic

• dephosphorylation of 6b (Supporting Information File 1, Figure S33) after the addition of ALP. In addition to the TEM images, we used circular dichroism (CD) to reveal the secondary structures of the assemblies before and after enzymatic action. The spectra show a significant change in the signal upon ALP treatment

• for 1, but merely slight changes for 4a and 6b, which are consistent with the TEM images (Supporting Information File 1, Figure S34). The differences in the morphological transition between 1 and 4a or 6b revealed by TEM and CD suggest that the shape-shifting (from nanoparticles to nanofibers) likely

Green synthesis of C5–C6-unsubstituted 1,4-DHP scaffolds using an efficient Ni–chitosan nanocatalyst under ultrasonic conditions

• Soumyadip Basu,
• Sauvik Chatterjee,
• Suman Ray,
• Suvendu Maity,
• Prasanta Ghosh,
• Asim Bhaumik and
• Chhanda Mukhopadhyay

Beilstein J. Org. Chem. 2022, 18, 133–142, doi:10.3762/bjoc.18.14

• H-bonding. The presence of diffraction peaks at 2Θ 9.2 and 19.7 (in degree) indicated the presence of a chitosan framework [28], whereas the other minor diffraction peaks were observed due to the presence of Ni(II). From the SEM and TEM images of the catalyst, we confirmed the morphological features

• of the material (Figure 3a and Figure 3b). The TEM images showed agglomeration of spherical NPs, leading to the formation of multiple scaffolds. In the SEM images, the presence of spheres of 40–60 nm was clearly visible (Figure 3c and Figure 3d). Often, these small NPs were agglomerated to form

• bigger particles of over 100 nm. The agglomeration of the TEM samples occurred upon solvent evaporation after the sample had been drop-casted on the carbon-coated Cu grid. This might have happened due to specific surface interactions of the particles. On the other hand, the SEM sample was prepared under

Exfoliated black phosphorous-mediated CuAAC chemistry for organic and macromolecular synthesis under white LED and near-IR irradiation

• Azra Kocaarslan,
• Zafer Eroglu,
• Önder Metin and
• Yusuf Yagci

Beilstein J. Org. Chem. 2021, 17, 2477–2487, doi:10.3762/bjoc.17.164

• azide groups decomposed at higher temperature. The IR spectrum of the cross-linked polymer further demonstrates the formation of a triazole ring by the decrease of the azide peak at 2100 cm−1 (Figure 6b). Representative TEM images recorded at different magnifications of the resulting cross-linked

• polymer are shown in Figure 7. From the TEM images, it can be concluded that the process leads to the formation of BPNs-embedded cross-linked polymers. The darker regions circled with yellow dashed line in Figure 6a were attributed to the BPNs while the other relatively lighter regions were ascribed to

• the cross-linked polymer. To further prove the existence of BPNs in the cross-linked structure, a high-angle annular dark-field scanning TEM (HAADF-STEM) image and the associated elemental mapping images for C, N, and P were recorded and depicted in Figure 7c and 7d. The elemental mapping images

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

• at the start of the reaction and after 45 min tuned to 8.3 to allow maximum conjugation efficiency. After removing excess TPP-COOH and coupling reagents via dialysis in Milli-Q water, the particles were adjusted to 4 mg mL−1 and analysed using DLS experiments and TEM microscopy (Figure 1). The

• and TEM microscopy. Control experiment: attachment of TPP-COOH to PP3 copolymer For the control experiment, PP3 (19.30 mg, 0.85 mmol of RAFT end group, 1 equiv) was dissolved in 1.5 mL of Milli-Q water and TPP-COOH (1.88 mg, 4.25 mmol, 5 equiv to RAFT end group), EDC·HCl (0.82 mg, 4.25 mmol, 5 equiv

• × 7H, S-CH2-C=O of PENAO), 3.46 (36 × 3H, OCH3), 1.7–2.1 (140H, CH2 backbone), 1.5 (7 × 6H, CH3 PENAO), 0.7–1.2 (210H, CH3 backbone). (I) DLS of PPM-NP4, MPM-NP2, PPM-NP4-TPP and MPM-NP2-TPP and (II) TEM of PPM-NP4-TPP and MPM-NP2-TPP (stained with uranyl acetate). Note: The curves of PPM-NP4-TPP and

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

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

• ]. Mono- or multi-fluorinated compounds were obtained in good yields (30–47%) with average DPs ranging from 9 to 15. The multifluorinated compound crystallized in a new cellulose allomorph. AFM and TEM images confirmed the formation of long platelets for monofluorinated compounds, similar to those

Antiviral therapy in shrimp through plant virus VLP containing VP28 dsRNA against WSSV

• Santiago Ramos-Carreño,
• Ivone Giffard-Mena,
• Jose N. Zamudio-Ocadiz,
• Alfredo Nuñez-Rivera,
• Ricardo Valencia-Yañez,
• Jaime Ruiz-Garcia,
• Maria Teresa Viana and
• Ruben D. Cadena-Nava

Beilstein J. Org. Chem. 2021, 17, 1360–1373, doi:10.3762/bjoc.17.95

• electron microscope equipped with a digital camera operated at 200 keV. The size of the VLPs was measured using the ImageJ (U.S. NIH) software from digital recorded TEM images. Shrimp and rearing conditions. P. vannamei postlarvae (PL) were grown in 2,500 L circular tanks containing seawater (34 ppt

• to the wild type CCMV (lane 2 and 3, respectively, in Figure 1). In contrast, the free dsRNAvp28 ran faster (lane 4 in Figure 1) in comparison with the sample and wild type CCMV, as an indication of VLPs formation. The VLPs assembly at each stage was analyzed by transmission electron microscopy (TEM

• report showing a long dsRNA encapsidation using a plant virus capsid protein. The analysis by EMSA showed that the VLPs that self-assemble migrate differently than the free dsRNAi (Figure 1, lane 4). After dialysis in assembly buffer (pH 7.2), the sample analysis by TEM shows the spherical procapsids

Enhanced target cell specificity and uptake of lipid nanoparticles using RNA aptamers and peptides

• Roslyn M. Ray,
• Anders Højgaard Hansen,
• Maria Taskova,
• Bernhard Jandl,
• Jonas Hansen,
• Citra Soemardy,
• Kevin V. Morris and
• Kira Astakhova

Beilstein J. Org. Chem. 2021, 17, 891–907, doi:10.3762/bjoc.17.75

• assessed by nanoparticle tracking analysis (NTA, Table 3) and transmission electron microscopy (TEM, Supporting Information File 1, Figure S2). After postinsertion, LNP sizes were found by NTA to range from 54–66 nm (Table 3), while TEM analysis revealed average sizes between 45–52 nm (Supporting

• Information File 1, Figure S2B). While there appears to be a ≈10 nm discrepancy when comparing DLS and NTA with TEM, this size difference was found to be consistent between these methods of analyses for all samples. For example, LNP B9 A-1 Tat was characterized by the smallest average size using both NTA (≈54

• nm) and TEM (≈45 nm). Thus, the average sizes obtained by NTA are in agreement with the average size observed using TEM (Supporting Information File 1, Figure S2A and Table S2). Similarly, while the mean diameter of LNP B9 G-3 was found to be larger by DLS (91.9 nm) than the values reported for NTA

β-Lactamase inhibition profile of new amidine-substituted diazabicyclooctanes

• Zafar Iqbal,
• Lijuan Zhai,
• Yuanyu Gao,
• Dong Tang,
• Xueqin Ma,
• Jinbo Ji,
• Jian Sun,
• Jingwen Ji,
• Yuanbai Liu,
• Rui Jiang,
• Yangxiu Mu,
• Lili He,
• Haikang Yang and
• Zhixiang Yang

Beilstein J. Org. Chem. 2021, 17, 711–718, doi:10.3762/bjoc.17.60

• , sulbactam and tazobactam [13] evolved as the BLIs of class A, B and few of class D β-lactamases [14]. These inhibitors were advantageous to clavulanic acid due to their lack of chromosomal induction of AmpC but found susceptible to a few of class A enzymes such as TEM type [10] and CTX-M (ESBL), identified

A new and efficient methodology for olefin epoxidation catalyzed by supported cobalt nanoparticles

• Lucía Rossi-Fernández,
• Viviana Dorn and
• Gabriel Radivoy

Beilstein J. Org. Chem. 2021, 17, 519–526, doi:10.3762/bjoc.17.46

• confirming the heterogeneous nature of the catalytic method. The freshly prepared CoNPs/MgO catalyst was characterized by means of transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDX), inductively coupled plasma atomic emission spectroscopy (ICP-AES), X-ray diffraction (XRD) and

• X-ray photoelectron spectroscopy (XPS) (see Supporting Information File 1). TEM analysis showed the presence of highly dispersed spherical cobalt nanoparticles, most of them ranging between 6 and 11 nm in size (Figure 1). EDX analysis in various regions of the sample (Figure S2, Supporting

• determined with a Shimadzu GC-14B instrument equipped with a flame-ionisation detector and a 30 m column (HP-5MS, 0.25 mm, 0.25 μm), using nitrogen as carrier gas. Catalyst characterization The freshly prepared catalyst was characterized by transmission electron microscopy (TEM) in a JEOL 100CX2 instrument

Supramolecular polymerization of sulfated dendritic peptide amphiphiles into multivalent L-selectin binders

• David Straßburger,
• Svenja Herziger,
• Katharina Huth,
• Moritz Urschbach,
• Rainer Haag and
• Pol Besenius

Beilstein J. Org. Chem. 2021, 17, 97–104, doi:10.3762/bjoc.17.10

• the effect of sulfate modification on the self-assembly properties of the dendritic peptide amphiphiles were performed using circular dichroism (CD) spectroscopy and electron transmission microscopy (TEM) as well as cryogenic TEM. Finally, the binding affinity of the sulfated supramolecular polymers

• we have assigned this characteristic CD band to a β-sheet-dominated short-range ordering of oligopeptide monomers, which is stable over a wide concentration range [30][39][40]. The application of transmission electron microscopy (TEM) gave further insight into the morphology of the assemblies induced

• by the secondary structure formation (Figure 1). All samples for convential TEM imaging were prepared by placing 5 μL of the aqueous solution on a sample grid for 1 min, followed by the removal of the excess liquid using a filter paper and subsequent negative staining using a 2% uranyl acetate

Control over size, shape, and photonics of self-assembled organic nanocrystals

• Chen Shahar,
• Yaron Tidhar,
• Yunmin Jung,
• Haim Weissman,
• Sidney R. Cohen,
• Ronit Bitton,
• Iddo Pinkas,
• Gilad Haran and
• Boris Rybtchinski

Beilstein J. Org. Chem. 2021, 17, 42–51, doi:10.3762/bjoc.17.5

• medium. The ONCs have a thin rectangular shape, with an aspect ratio that is controlled by the content of the organic cosolvent (THF). The nanocrystals were characterized in solution by cryogenic transmission electron microscopy (cryo-TEM) and small-angle X-ray scattering. The ONCs retain their structure

• upon drying, as was evidenced by TEM and atom force microscopy. Photophysical studies, including femtosecond transient absorption spectroscopy, revealed a distinct influence of the ONC morphology on their photonic properties (excitation energy transfer was observed only in the high-aspect ONCs

• (cryo-TEM) and TEM studies revealed that the 10% THF assemblies were long rectangular-shaped crystals, ≈3 µm in length (Figure 2A). The crystals had an aspect ratio of 2.6 ± 1.3, and their crystalline order was evident from FFT analysis, exhibiting well-defined spots corresponding to a periodicity of

A novel and robust heterogeneous Cu catalyst using modified lignosulfonate as support for the synthesis of nitrogen-containing heterocycles

• Bingbing Lai,
• Meng Ye,
• Ping Liu,
• Minghao Li,
• Rongxian Bai and
• Yanlong Gu

Beilstein J. Org. Chem. 2020, 16, 2888–2902, doi:10.3762/bjoc.16.238

• ) conditions. ICP-MS data were recorded on ELAN DRC-e device. The morphologies of samples were observed by scanning electron microscopy (SEM, Sirion 200, Holland) equipped with an energy dispersive X-ray (EDX) spectroscopy and transmission electron microscopy (TEM, Talos F200X), respectively. 1H and 13C NMR

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

• supported by rheological measurements [42] and finally validated by transmission electron microscopy at cryogenic temperature (cryo-TEM) [43]. Temperature-dependent rheology Next, the temperature dependence of the rheology for the RWLM will be described. Oscillatory-shear experiments were performed for the

Easy access to a carbohydrate-based template for stimuli-responsive surfactants

• Thomas Holmstrøm,
• Daniel Raydan and
• Christian Marcus Pedersen

Beilstein J. Org. Chem. 2020, 16, 2788–2794, doi:10.3762/bjoc.16.229

• distance of the two lipophilic tails resulting in a self-assembly of the molecules into larger aggregates that could be characterized with DLS and TEM [11]. In a previous study by Yuasa et al., it was shown that the distance between the two groups on the anomeric and the 3-position indeed decreased upon a

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

• hydrogelation occurs after proteinase K catalytically produces more Nap-ffky for self-assembly. In addition, unlike the FLAG-tag-based branched peptides [32], 1 and 2 are proteolytic-resistant to enterokinase (ENTK, Figures S3 and S4, Supporting Information File 1). We used TEM to examine the nanoscale

• morphology changes before and after the addition of proteinase K to solutions of 1 and 2. TEM revealed the solutions of 1 and 2 (500 μM) to contain nanoparticles of 11 ± 2 nm in diameter, indicating that the acetylation at the branch affects the self-assembly of the branched peptides only slightly. Upon the

• increased to 5 mM and 10 mM, TEM revealed that the solutions contained nanoparticles, suggesting that the negatively charged branches in the micelles prevent the formation of worm-like micelles due to increasing the concentration of 1 or 2. After the addition of proteinase K to the solution of 1 (5 mM) or 2

Optical detection of di- and triphosphate anions with mixed monolayer-protected gold nanoparticles containing zinc(II)–dipicolylamine complexes

• Lena Reinke,
• Julia Bartl,
• Marcus Koch and
• Stefan Kubik

Beilstein J. Org. Chem. 2020, 16, 2687–2700, doi:10.3762/bjoc.16.219

• signals of the immobilized ligand molecules but no sharp signals, showing that the nanoparticles were not contaminated with unbound ligands or residual citrate. According to transmission electron microscopy (TEM), NPrac-1 had an average diameter of 9.1 ± 2.4 nm and a maximum of the SPR band in the UV–vis

• large but nevertheless provided a rough estimate of the nanoparticle composition. The latter was calculated by assuming spherical nanoparticles with an average diameter of 9.1 nm, as determined by TEM. The AuNP volume thus amounted to 395 nm3 and the surface area to 260 nm2. Considering that the density

• the aggregates were stable only in a narrow concentration range. A further salt addition caused the nanoparticles to precipitate presumably because they became insoluble when they increased in size. To confirm this assumption, we also followed the effect of the salts on the AuNPs by TEM. According to

Palladium nanoparticles supported on chitin-based nanomaterials as heterogeneous catalysts for the Heck coupling reaction

• Tony Jin,
• Malickah Hicks,
• Davis Kurdyla,
• Sabahudin Hrapovic,
• Edmond Lam and
• Audrey Moores

Beilstein J. Org. Chem. 2020, 16, 2477–2483, doi:10.3762/bjoc.16.201

• Information File 1) [16]. ChNCs were treated with ammonium persulfate (APS) for 16 h to form disperse ChNCs after washing. ChsNCs were made by deacetylating ChNCs in the presence of concentrated NaOH as well as a small amount of NaBH4 (Scheme 1). As seen through transmission electron microscopy (TEM) in

• nanocrystals were well separated. Larger aggregates of the individual nanocrystals were also observed in all samples. Glow-discharged carbon-coated TEM grids were used, along with uranyl acetate as a negative stain in order to provide higher contrast to the individual rods. Further characterization of the

• for PdNP@ChNC and PdNP@ChsNCs were −13.9 and +57.9 mV, respectively. PdNP@ChsNCs were, again, far more suspendable in aqueous solution as compared to PdNP@ChNCs. TEM micrographs of PdNP@ChNC (Figure 2a) and PdNP@ChsNC (Figure 2b) confirmed complete immobilization of Pd NPs onto both the ChNC and ChsNC