Glycosystems in nanotechnology: Gold glyconanoparticles as carrier for anti-HIV prodrugs

• Fabrizio Chiodo,
• Marco Marradi,
• Javier Calvo,
• Eloisa Yuste and
• Soledad Penadés

Beilstein J. Org. Chem. 2014, 10, 1339–1346, doi:10.3762/bjoc.10.136

• ; d, doublet; t, triplet; q, quartet; m, multiplet. For transmission electron microscopy (TEM) examinations, a single drop (10 µL) of an aqueous solution (ca. 0.1 mg/mL in milli-Q water) of drugs-GNPs was placed onto an ultrathin carbon film (<3 nm thickness) supported by a lacey carbon film on a 400

• mesh copper grid (Ted Pella). The solution on the grid was left to dry in air for 14 hours at room temperature. TEM analysis was carried out in a JEOL JEM-2100F-UHR, operated at 200 kV. UV–vis spectra were carried out with a Beckman Coulter DU 800 spectrometer. The mass spectrometry detection was

Polyglycerol-functionalized nanodiamond as a platform for gene delivery: Derivatization, characterization, and hybridization with DNA

• Li Zhao,
• Yuki Nakae,
• Hongmei Qin,
• Tadamasa Ito,
• Takahide Kimura,
• Hideto Kojima,
• Lawrence Chan and
• Naoki Komatsu

Beilstein J. Org. Chem. 2014, 10, 707–713, doi:10.3762/bjoc.10.64

• kV accelerating voltage for the TEM model. All samples for electron microscopy were prepared by evaporating one drop (~50 µL) of samples on ultrathin carbon-coated copper grids. Thermogravimetric analyses (TGA) were carried out by a Q-50 analyzer (TA instruments) with a heating rate of 20 °C/min

A³-Coupling catalyzed by robust Au nanoparticles covalently bonded to HS-functionalized cellulose nanocrystalline films

• Jian-Lin Huang,
• Derek G. Gray and
• Chao-Jun Li

Beilstein J. Org. Chem. 2013, 9, 1388–1396, doi:10.3762/bjoc.9.155

• novel nanocomposite catalyst AuNPs@HS-CNC. The uniform, fine AuNPs were made by the reduction of HAuCl4 solution with thiol (HS-) group-functionalized CNC films. The AuNPs@HS-CNC nanocomposites were examined by X-ray photoelectron spectroscopy (XPS), TEM, ATR-IR and solid-state NMR. Characterizations

• metallic states (Au0). TEM pictures in Figure 2 further confirm this result. The HRTEM images in Figure S1 clearly show the size (2–3 nm) and lattice of the Au nanoparticles on the surface of the Au@HS-CNC (4.4 mol %) catalyst. The S species were mainly present in −2 states, corresponding to HS-groups with

• diminish the environmental impact of such reactions. Other immobilized metallic nanoparticle catalysts could also be designed based on the present method, which offered more opportunities for greener organic synthesis. Au4f and S2p XPS spectra of the Au@HS-CNC (4.4 mol %) catalyst. TEM pictures of the HS

Linkage of α-cyclodextrin-terminated poly(dimethylsiloxanes) by inclusion of quasi bifunctional ferrocene

• Helmut Ritter,
• Berit Knudsen and
• Valerij Durnev

Beilstein J. Org. Chem. 2013, 9, 1278–1284, doi:10.3762/bjoc.9.144

• the derivatives mechanically. In addition, the successful complexation of the α-CD-modified siloxanes and the formation of supramolecular structures via inclusion complexes with ferrocene can be illustrated in the TEM images of 4 (Figure 5). Figure 5A (α-CD-disiloxane 4) shows a majority of globular

• of α-CD-modified disiloxane 4 (dashed line) can be determined as 343 nm, which corresponds to the average sizes of the particles observed by TEM measurements. After the addition of ferrocene, the resulting complex with 4 was investigated by DLS (solid line) as well. The hydrodynamic diameter

• observed in the TEM images. This further confirms the assumption that the terminally functionalized poly(dimethylsiloxanes) can assemble to supramolecular structures through noncovalent interactions. Conclusion We have demonstrated, for the first time, a chain extension of poly(dimethylsiloxanes) in

The synthesis of well-defined poly(vinylbenzyl chloride)-grafted nanoparticles via RAFT polymerization

• John Moraes,
• Kohji Ohno,
• Guillaume Gody,
• Thomas Maschmeyer and
• Sébastien Perrier

Beilstein J. Org. Chem. 2013, 9, 1226–1234, doi:10.3762/bjoc.9.139

• polymerization with an average value of 0.11 chains/nm2 (compared to 0.18 chains/nm2 if the Mn of the free chains is used for calculation). Transmission electron microscope (TEM) analysis of the particles recovered from the reaction shows that as the reaction proceeds, the polymer shell around the particles

• increases in size (Figure 6). The polymer shell is visible as the dark grey region between the particles, and it increases in size from 10% conversion (57,600 g/mol, grafted polymer) to 54% conversion (208,000 g/mol, grafted polymer). TEM samples of particles recovered from intermediate stages of the

• polymerization are included in Supporting Information File 1, Figure S6. It should be noted that TEM images of the particles show the average diameter of the particles to be smaller than that measured by DLS. We ascribe this to the fact that the polymer shell on the particles in DLS analysis is measured in a

The conjugation of nonsteroidal anti-inflammatory drugs (NSAID) to small peptides for generating multifunctional supramolecular nanofibers/hydrogels

• Jiayang Li,
• Yi Kuang,
• Junfeng Shi,
• Yuan Gao,
• Jie Zhou and
• Bing Xu

Beilstein J. Org. Chem. 2013, 9, 908–917, doi:10.3762/bjoc.9.104

• self-assembly in water. Transmission electron microscopy (TEM) In addition to the macroscopic phase transition such as hydrogelation, another hallmark of molecular self-assembly in water is the formation of ordered nanostructures (e.g., nanofibers or nanoparticles). As revealed by the TEM images

• (Figure 2), the hydrogel of 1a comprises long nanofibers that entangle to form the network. The widths of nanofibers in the gel of 1a appear to be nonuniform, displaying minimum width at 6 nm and maximum width at 20 nm (Figure 2A). The TEM image of the hydrogel of 1b shows helical and rigid nanofibers

• 2a comprises two kinds of nanostructures, i.e., nanofibers and nanoparticles, visible in the TEM images. As shown in Figure 2E, long nanofibers with an average width of 17 nm entangle together to form larger helical nanofibers with an average width of 30 nm. Higher-magnification TEM shows that the

Cyclodextrin-based nanosponges as drug carriers

• Francesco Trotta,
• Marco Zanetti and
• Roberta Cavalli

Beilstein J. Org. Chem. 2012, 8, 2091–2099, doi:10.3762/bjoc.8.235

• nanosponges [36]. TEM studies showed that the particle sizes of ASA-loaded nanosponges have average diameters ranging from 40 to 60 nm and they were seen to have a regular spherical shape. Zeta potential was high enough to obtain a stable colloidal formulation. In vitro and in vivo studies indicated a slow

• molecules in nanomedicine. Molecular structure of cyclodextrin carbonate nanosponges. TEM microphotograph of cyclodextrin carbonate nanosponge (magnification 46,000×). Synthetic routes to cyclodextrin nanosponges. (a) Cyclodextrin carbonate nanosponges. (b) Cyclodextrin carboxylate nanosponges. Molecules

Self-assembled organic–inorganic magnetic hybrid adsorbent ferrite based on cyclodextrin nanoparticles

• Ângelo M. L. Denadai,
• Frederico B. De Sousa,
• Joel J. Passos,
• Fernando C. Guatimosim,
• Kirla D. Barbosa,
• Ana E. Burgos,
• Fernando Castro de Oliveira,
• Jeann C. da Silva,
• Bernardo R. A. Neves,
• Nelcy D. S. Mohallem and
• Rubén D. Sinisterra

Beilstein J. Org. Chem. 2012, 8, 1867–1876, doi:10.3762/bjoc.8.215

• thermal analysis (TG/DTA), and by their magnetic behavior in aqueous suspension (see Supporting Information File 1). Fe-Ni/Zn and Fe-Ni/Zn/βCD nanoparticles morphologies were investigated in the solid state by scanning electronic microscopy (SEM), transmission electronic microscopy (TEM), and atomic force

• different aggregation levels, these materials were investigated in the solid state by SEM, TEM and AFM and also in aqueous suspension by using DLS. AFM images of Fe-Ni/Zn and Fe-Ni/Zn/βCD are presented in Figure 1. Based on these images, nanoparticles below 100 nm were verified for these materials. Looking

• ferrite synthesis, preventing the particles growing during the ferrite synthesis (nucleation process). In order to gain insight into the microstructure of these assembled materials, SEM and TEM were also carried out. TEM images of the magnetic materials, demonstrating their structure from the nanoscale

Polysiloxane ionic liquids as good solvents for β-cyclodextrin-polydimethylsiloxane polyrotaxane structures

• Narcisa Marangoci,
• Rodinel Ardeleanu,
• Laura Ursu,
• Constanta Ibanescu,
• Maricel Danu,
• Mariana Pinteala and
• Bogdan C. Simionescu

Beilstein J. Org. Chem. 2012, 8, 1610–1618, doi:10.3762/bjoc.8.184

• damaging them, through the use of partial water vapor pressure in the microscope specimen chamber. Samples preparation A holey-carbon-coated copper grid was placed on a TEM sample holder and positioned on a Peltier cooling stage. The samples were diluted in THF, and then a small amount of solution was

Control over molecular motion using the cis–trans photoisomerization of the azo group

• Estíbaliz Merino and
• María Ribagorda

Beilstein J. Org. Chem. 2012, 8, 1071–1090, doi:10.3762/bjoc.8.119

• ), electronic transmission images (TEM), UV–vis and X-ray analysis, setting a pore diameter of 1.9 ± 0.1 nm, a volume of 0.248 cm−3∙g−1 and a surface area of 621.19 m2∙g−1. The nanoparticles, which contain 2.4% by weight of azobenzene, are treated with camptothecin (CPT), a drug used in the treatment of cancer

Cyanoethylation of the glucans dextran and pullulan: Substitution pattern and formation of nanostructures and entrapment of magnetic nanoparticles

• Kathrin Fiege,
• Heinrich Lünsdorf,
• Sevil Atarijabarzadeh and
• Petra Mischnick

Beilstein J. Org. Chem. 2012, 8, 551–566, doi:10.3762/bjoc.8.63

• specific interaction between cyano groups and iron could be proven. The size distribution and morphology of the nanoparticles were analyzed by dynamic light scattering (DLS), scanning electron microscopy (SEM) and energy-filtered transmission electron microscopy (EF–TEM) with parallel electron energy loss

• were fixed with strong magnets and washed with distilled water. Monodisperse and regularly shaped iron oxide nanoparticles were obtained as shown by TEM (Figure 9). The iron concentration of the nanoparticle dispersion, as analyzed with inductively coupled plasma optical emission spectroscopy (ICP–OES

• ), was 37.2 g/kg. The particle size was calculated by image data processing of the TEM micrograph resulting in a mean diameter of 12.2 nm ± 2.6 nm. The hydrodynamic diameter was estimated at 27 nm by dynamic light scattering (DLS) measurements. Agglomeration or aggregation processes were prohibited by pH

Liquid-crystalline nanoparticles: Hybrid design and mesophase structures

• Gareth L. Nealon,
• Romain Greget,
• Cristina Dominguez,
• Zsuzsanna T. Nagy,
• Daniel Guillon,
• Jean-Louis Gallani and
• Bertrand Donnio

Beilstein J. Org. Chem. 2012, 8, 349–370, doi:10.3762/bjoc.8.39

• of a sample in the mesophase range on a TEM grid, followed by quenching to RT (Figure 5). Imaging of the material by TEM revealed 13–60 nm long strings of NPs, with an interstring distance of approximately 5.8 nm (i.e., roughly twice the length of the organic ligands) and an interparticle distance

• -ray and TEM techniques. The hybrids coated with primary dodecane- and hexanethiol layers (Au@C12/13 and Au@C6/13) displayed optically isotropic phases above 126 °C and 119 °C, respectively (Table 2), but a birefringent threaded texture typical of a nematic phase below these temperatures (Figure 15

• columns displaced along the z-axis by 0, c/3 and 2c/3 (Figure 16a). The structure of the LC phase was also confirmed by TEM observation, whereby a triangular lattice is observed when viewing the phase down the [001] axis, and stripes are observed when the sample is viewed perpendicular to the direction

Continuous preparation of carbon-nanotube-supported platinum catalysts in a flow reactor directly heated by electric current

• Alicja Schlange,
• Antonio Rodolfo dos Santos,
• Ulrich Kunz and
• Thomas Turek

Beilstein J. Org. Chem. 2011, 7, 1412–1420, doi:10.3762/bjoc.7.165

• effect. TEM micrographs of both catalyst samples are demonstrated in Figure 4. Cluster size histograms and the average cluster size are also shown. It can be clearly seen that for the catalyst prepared in the tubular reactor Pt particles are homogenously dispersed on carbon nanotubes. Particles range

• observed as shown in Figure 4. The fact that some isolated platinum particles can be observed in the sample prepared in the tubular reactor can be attributed to the dispersion method employed during the TEM sample preparation. These results reveal that the catalyst preparation method strongly influences

• cluster sizes calculated for Pt/CNT catalysts prepared with the tubular reactor were measured as 1.77 nm, 1.74 nm and 1.77 nm. These results are in agreement with results determined by TEM analysis. For the reference Pt/CNT catalyst (not shown in Figure 5) the Pt cluster size calculated with the Scherrer

Scaling up of continuous-flow, microwave-assisted, organic reactions by varying the size of Pd-functionalized catalytic monoliths

• Ping He,
• Stephen J. Haswell,
• Paul D. I. Fletcher,
• Stephen M. Kelly and
• Andrew Mansfield

Beilstein J. Org. Chem. 2011, 7, 1150–1157, doi:10.3762/bjoc.7.133

• conditions. The high catalytic activity of the Pd-monolith catalysts in Suzuki–Miyaura reactions can be attributed to the following three factors. First is the high dispersion of small Pd particles over the substrate surface within the monolith mesopores. The TEM image (Figure 4) shows that the catalyst

• (thickness approximately 2 nm) by a SEMPREP 2 Sputter Coater (Nanotech Ltd.). Transmission electron microscopy (TEM) was carried out on a JEOL-2010 operating at 200 kV. The BET surface area and nm-scale pore-size distribution were obtained by measuring N2 adsorption and desorption isotherms at 77 K by means

• . Reactivity of the Pd-monolith-3.2 and Pd-monolith-6.4 for the Suzuki–Miyaura reaction between bromobenzene (0.1 M) and phenylboronic acid (0.12 M): The dependence of micromoles of product obtained on contact time. TEM image of Pd-monolith catalyst (scale bar: 100 nm). Suzuki–Miyaura reaction of bromobenzene

Air-stable, recyclable, and time-efficient diphenylphosphinite cellulose-supported palladium nanoparticles as a catalyst for Suzuki–Miyaura reactions

• Qingwei Du and
• Yiqun Li

Beilstein J. Org. Chem. 2011, 7, 378–385, doi:10.3762/bjoc.7.48

• transmission electron microscopy (TEM). The Pd loading was determined to be 0.33 mmol/g by ICP-AES. The IR spectra of Cell–OPPh2 and Cell–OPPh2–Pd0 catalysts were recorded. The IR spectrum of Cell–OPPh2 contained absorption bands at 1029.9 cm−1 for C–O–P bond. This band is negatively shifted to 1028.8 cm−1 in

• morphology of Cell–OPPh2–Pd0 and Cell–OPPh2 was studied by SEM and TEM. A clear change in morphology is observed after anchoring palladium onto the polymer support (Figure 3). The TEM image of the Cell–OPPh2–Pd0 catalyst shows that the average size of the nanopalladium particles is in the range of 4–15 nm

• (Figure 4a). The TEM image of the used catalyst indicates that the size and morphology of the nanopalladium has suffered slightly from agglomeration in the recovered catalyst after being reused six times (Figure 4b). Suzuki–Miyaura cross-coupling reactions To explore the efficiency of the

Exceptionally small supramolecular hydrogelators based on aromatic–aromatic interactions

• Junfeng Shi,
• Yuan Gao,
• Zhimou Yang and
• Bing Xu

Beilstein J. Org. Chem. 2011, 7, 167–172, doi:10.3762/bjoc.7.23

• represents the lowest molecular weight (MW = 295.33 g/mol) peptide-based hydrogelator prepared to date. The supramolecular hydrogels were characterized by transmission electron micrograph (TEM) and fluorescence spectroscopy, and the results obtained by both techniques correlate well with their rheological

• , which agrees with the morphology as revealed by TEM (Figure 4). Figure 4 shows the TEM images of the matrices of gels I to IV. The phenylalanine based hydrogelator self-assemble into nanofibers that physically cross-link to form a fibrous network as the matrix of hydrogel. For example, the fibers in gel

• III (Figure 4C) are longer and larger than those in gel II (Figure 4B), agreeing with the fact that gel III has a larger critical strain and higher storage modulus. In the TEM image of gel IV (Figure 4D), the fibers are smaller and longer than other gels, which could contribute to its relative high

Miniemulsion polymerization as a versatile tool for the synthesis of functionalized polymers

• Daniel Crespy and
• Katharina Landfester

Beilstein J. Org. Chem. 2010, 6, 1132–1148, doi:10.3762/bjoc.6.130

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

• with transmission electron microscopy (TEM). The TEM image (Figure 2c), of the dried R-3 gel in octane (1 mM) exhibited entangled fibrillar network formation although the concentration stays well below the CGC value (2.3 mM) in this solvent. The critical gelation concentration indicates the threshold

• then observed under a FEI Quanta 3D FEG microscope. The transmission electron microscopy was carried out by drop casting a solution (1 mM in octane) on a carbon coated copper grid and viewed under FEI Tecnai 20. TEM grids (R2/2 Quantifoil Jena) were purchased from Quantifoil. Concentration-dependent 1H

• 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

• ) and diesters (3b, 4b). It appears that the increased hydrogen bonding potential of terminal diamide derivatives provides somewhat more versatile gelators capable of gelating solvents of medium and low polarity where intermolecular hydrogen bonding is favored. TEM and DSC investigations As reported

• previously, TEM investigations of bis(amino acid)oxalamide gels revealed in most cases formation of very dense networks consisting of heavily entangled tiny fibers with diameters in the range of 10–20 nm [58][59][60]. A similar morphology was observed for the bis(PhePhe)-5a-EtOH gel (fiber d’s 6–20 nm) and

• bis(PhgLeu) 4a water/DMSO gel (fiber d’s 5–15 nm) (see Supporting Information File 1, Figure S1a,b). TEM images of diastereomeric (S,S)-1a and (S,R)-1a water/DMSO gels (Figure 2 and Figure 3) show highly distinct morphology of gel networks. In the first gel rather straight fibers and fiber bundles

Hybrid biofunctional nanostructures as stimuli-responsive catalytic systems

• Gernot U. Marten,
• Thorsten Gelbrich and
• Annette M. Schmidt

Beilstein J. Org. Chem. 2010, 6, 922–931, doi:10.3762/bjoc.6.98

• ATRP is qualitatively analyzed by transmission electron microscopy (TEM) and ATR-IR spectroscopy [33] on carefully washed and dried particles. TEM images (Figure 2) of the obtained nanoparticles demonstrate strongly contrasting Fe3O4 cores surrounded by less contrasting polymer shells. The nearly

• were collected on a Mettler-Toledo DSC 822e at 5 K·min−1. TEM pictures were taken on a Hitachi H 600. Structures of comonomers employed in the synthesis of functional core–shell particles. TEM images of a) Fe3O4 nanoparticles electrostatically stabilized by citric acid; b) Fe3O4@P(M100) nanoparticles

• . Müller, HHU Düsseldorf, for the use of the temperature controlled UV–vis spectrometer and Prof. H. Ritter, HHU Düsseldorf for generous support. We also thank C. Schlemmer, ALU Freiburg, for recording TEM pictures. We gratefully acknowledge DFG (Emmy Noether Program, priority program SPP 1259) and FCI (A

C-Arylation reactions catalyzed by CuO-nanoparticles under ligand free conditions

• Mazaahir Kidwai,
• Saurav Bhardwaj and
• Roona Poddar

Beilstein J. Org. Chem. 2010, 6, No. 35, doi:10.3762/bjoc.6.35

• differences which have been shown in the TEM image. The number of reactive sites on the surface is small in the case of larger crystallites and considerably greater in the case of smaller crystallites (Figure 1). To investigate further the surface morphology of CuO-nanoparticles, powder XRD and TEM images

• of the reaction mixture and washed thoroughly with ethyl acetate. The resulting nanoparticles could be reused for several cycles without any significant loss of activity. In our study, we used same nanoparticles three times and the results are summarized below (Table 5). The TEM and XRD analysis of

• NMR). Powder X-ray diffraction pattern and TEM image of nano CuO (fresh). Proposed reaction pathway for the CuO-nanoparticles catalyzed C–C coupling reaction. Powder X-ray diffraction pattern and TEM image of recycled CuO-nanoparticles. Synthesis of 3-phenylpentane-2,4-dione using CuO-nanoparticles

Symmetrical and unsymmetrical α,ω-nucleobase amide-conjugated systems

• Sławomir Boncel,
• Maciej Mączka,
• Krzysztof K. K. Koziol,
• Radosław Motyka and
• Krzysztof Z. Walczak

Beilstein J. Org. Chem. 2010, 6, No. 34, doi:10.3762/bjoc.6.34

• and 5′-amino-2′,5′-dideoxythymidine. The title compounds may find application as antiprotozoal agents. Moreover, preliminary microscopy TEM studies of supramolecular behaviour showed that target molecules with bolaamphiphilic structures were capable of forming highly ordered assemblies, mainly

• synthesis of unsymmetrical derivatives. Interestingly, considering the physicochemical aspect of our work, two of the compounds synthesised containing aliphatic long-chain linkages revealed a tendency to self-assemble in the initial TEM studies. Results and Discussion The subunits containing carboxylic

• the two model compounds 11 and 12. The supramolecular behaviour of conjugated nucleobase-based bolaamphiphiles was examined by TEM. A JEOL 200 FX, operating at 200 kV, was used to obtain the typical images as shown in Figure 4. For the microscopic studies, saturated ethanolic solutions of 11 and 12

Polyionic polymers – heterogeneous media for metal nanoparticles as catalyst in Suzuki–Miyaura and Heck–Mizoroki reactions under flow conditions

• Klaas Mennecke and
• Andreas Kirschning

Beilstein J. Org. Chem. 2009, 5, No. 21, doi:10.3762/bjoc.5.21

• removing traces of soluble Pd species. Top: Reactor (1–2 mL dead volume) with functionalized Raschig-rings; bottom: TEM-micrographs of Pd(0) nanoparticles on optimized polyionic gel (left and central) and Raschig-rings (right). Repeated Suzuki reaction of 4-bromotoluene (6) with phenylboronic acid (10