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Search for "nanoparticles" in Full Text gives 257 result(s) in Beilstein Journal of Organic Chemistry. Showing first 200.

An effective Pd nanocatalyst in aqueous media: stilbene synthesis by Mizoroki–Heck coupling reaction under microwave irradiation

  • Carolina S. García,
  • Paula M. Uberman and
  • Sandra E. Martín

Beilstein J. Org. Chem. 2017, 13, 1717–1727, doi:10.3762/bjoc.13.166

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  • an economic and environmental standpoint, it is highly desirable to develop more environmentally friendly synthetic methodologies. Several studies were dedicated to the design of a novel catalytic system, that are more accessible, robust, efficient and ligand-free [19]. In that sense, nanoparticles
  • . Synthesis of Pd nanoparticles suspension by electrochemical reduction The electrochemical synthesis of PVP-Pd NPs was carried out as previously reported [46]. The experiments were achieved in a glass electrochemical cell equipped with a Pt disc working electrode (geometric area = 0.0746 cm2), a very large
  • with tributyl(vinyl)stannane.a Supporting Information Supporting Information File 196: TEM images of Pd nanoparticles, characterization data, and NMR spectra. Acknowledgements The research was supported by CONICET, FONCyT and SECyT - UNC. C.S.G. gratefully acknowledges CONICET for the fellowships. We
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Published 18 Aug 2017

Block copolymers from ionic liquids for the preparation of thin carbonaceous shells

  • Sadaf Hanif,
  • Bernd Oschmann,
  • Dmitri Spetter,
  • Muhammad Nawaz Tahir,
  • Wolfgang Tremel and
  • Rudolf Zentel

Beilstein J. Org. Chem. 2017, 13, 1693–1701, doi:10.3762/bjoc.13.163

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  • monomer by RAFT polymerization. This allows the control over the molecular weight of ionic liquid blocks in the range of 8000 and 22000 and of the block-copolymer synthesis. In this work we focus on block copolymers with an anchor block. They can be used to control the formation of TiO2 nanoparticles
  • , which are functionalized thereafter with a block of ionic-liquid polymer. Pyrolysis of these polymer functionalized inorganic nanoparticles leads to TiO2 nanoparticles coated with a thin carbonaceous shell. Such materials may, e.g., be interesting as battery materials. Keywords: block copolymer; carbon
  • , thin shells of carbonaceous materials around inorganic nanoparticles have been intensively investigated recently [22][23][24][25]. This interest is related to the search for improved battery materials for the reversible storage of electricity. To further improve batteries in terms of energy and power
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Published 16 Aug 2017

Synthesis and metal binding properties of N-alkylcarboxyspiropyrans

  • Alexis Perry and
  • Christina J. Kousseff

Beilstein J. Org. Chem. 2017, 13, 1542–1550, doi:10.3762/bjoc.13.154

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  • nanoparticles has enabled photomodulation of nanoparticle fluorescence [10][11]. Similarly, tagged N-alkylcarboxyspiropyrans have provided the basis for photoactive biopolymers, e.g., polypeptides with photocontrolled folding [12], light-activated enzymes [13], light-enhanced affinity chromatography using
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Published 04 Aug 2017

Mechanochemistry-assisted synthesis of hierarchical porous carbons applied as supercapacitors

  • Desirée Leistenschneider,
  • Nicolas Jäckel,
  • Felix Hippauf,
  • Volker Presser and
  • Lars Borchardt

Beilstein J. Org. Chem. 2017, 13, 1332–1341, doi:10.3762/bjoc.13.130

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  • designing the porosity of carbon materials involves hard or soft templates [22][23][24]. Hard-templating utilizes metal oxide nanoparticles [25] and salts [26][27][28], which have to be synthesized in advance. Soft-templating employs surfactants or other structure-directing molecules, which self-assemble to
  • for the synthesis of uniform metal oxide nanoparticles to synthesize a titanium(IV) citrate-based polymer [44][45]. The Pechini method is applicable to synthesize templated mesoporous carbons [46][47][48][49], but has never been utilized for a solvent-free and rapid process based on mechanochemistry
  • . After carbonization broadened reflections occur due to the conversion of the bidenated Ti atoms to TiO2 nanoparticles of the rutile and anatase modification. We calculated the average domain size of crystalline TiO2 from the reflections at 25.4°, 48.0°, and 54.5° 2θ to be 6–9 nm after background
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Published 06 Jul 2017

Detection of therapeutic radiation in three-dimensions

  • John A. Adamovics

Beilstein J. Org. Chem. 2017, 13, 1325–1331, doi:10.3762/bjoc.13.129

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  • the study of alternative treatment approaches such as the addition of nanoparticles containing metals to the dosimeter to evaluate enhanced radiation effects [57] and utilizing mice in evaluating radiation treatment plans [58]. Conclusion Over the last twelve years there has been significant progress
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Published 05 Jul 2017

Sugar-based micro/mesoporous hypercross-linked polymers with in situ embedded silver nanoparticles for catalytic reduction

  • Qing Yin,
  • Qi Chen,
  • Li-Can Lu and
  • Bao-Hang Han

Beilstein J. Org. Chem. 2017, 13, 1212–1221, doi:10.3762/bjoc.13.120

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  • . As the prepared porous polymer SugPOP-1 is based on hemiacetal glucose, Ag nanoparticles (AgNPs) can be successfully incorporated into the polymer by an in situ chemical reduction of freshly prepared Tollens’ reagent. The obtained AgNPs/SugPOP-1 composite demonstrates good catalytic activity in the
  • reduction of 4-nitrophenol (4-NP) with an activity factor ka = 51.4 s−1 g−1, which is higher than some reported AgNP-containing composite materials. Keywords: catalytic reduction; hypercross-linking; porous polymers; silver nanoparticles; sugar; Introduction Hypercross-linked polymers (HCPs) are
  • functionalization of the materials. Silver nanoparticles (AgNPs) have received extensive attention because of their unique properties and applications in catalysis [18], antibacterial use [19], phase separation [20], surface-enhanced Raman scattering (SERS) [21], etc. Compared with bulk silver, AgNPs have a more
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Published 22 Jun 2017

Glyco-gold nanoparticles: synthesis and applications

  • Federica Compostella,
  • Olimpia Pitirollo,
  • Alessandro Silvestri and
  • Laura Polito

Beilstein J. Org. Chem. 2017, 13, 1008–1021, doi:10.3762/bjoc.13.100

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  • , Nanotechnology Lab., Via G. Fantoli 16/15, 20138 Milan, Italy 10.3762/bjoc.13.100 Abstract Glyco-gold nanoparticles combine in a single entity the peculiar properties of gold nanoparticles with the biological activity of carbohydrates. The result is an exciting nanosystem, able to mimic the natural multivalent
  • : gold nanoparticles; glyco nanoparticles; glyconanomaterials; immunology; targeting; Introduction Carbohydrates are well recognized as crucial biomolecules for their capability to produce an enormous number of biocodes which are translated into their ability to promote or suppress a plethora of
  • resulting biological processes [3][4]. The increasing ability to manipulate material at the nanosize allowed the development of many glyco nanoparticles helpful in a wide range of applications, from the drug delivery to the imaging [5][6][7]. Among the large number of nanomaterials, gold is one of the main
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Published 24 May 2017

Interactions between shape-persistent macromolecules as probed by AFM

  • Johanna Blass,
  • Jessica Brunke,
  • Franziska Emmerich,
  • Cédric Przybylski,
  • Vasil M. Garamus,
  • Artem Feoktystov,
  • Roland Bennewitz,
  • Gerhard Wenz and
  • Marcel Albrecht

Beilstein J. Org. Chem. 2017, 13, 938–951, doi:10.3762/bjoc.13.95

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  • persistent macromolecules with high structural rigidity are able to form stable aggregates based on multiple supramolecular interactions, which can be detected and quantified without the presence of side effects, such as self-passivation or coiling processes. Dendrimers, nanoparticles and shape-persistent
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Published 18 May 2017

Continuous-flow processes for the catalytic partial hydrogenation reaction of alkynes

  • Carmen Moreno-Marrodan,
  • Francesca Liguori and
  • Pierluigi Barbaro

Beilstein J. Org. Chem. 2017, 13, 734–754, doi:10.3762/bjoc.13.73

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  • alkadienes from alkene feedstocks [4][5]. The chemistry of these processes is dominated by heterogeneous palladium catalysts, particularly based on solid-supported Pd nanoparticles (PdNP) [6][7]. On the industrial scale, alkynes partial hydrogenations are usually carried out under batch conditions using
  • to handle, easy to operate and can accommodate beds with a broad range of physical dimensions and shapes. Commonly used packed catalysts consist of metal nanoparticles (MNP) immobilized onto a variety of porous solid supports, either pellets or powders of various grain size (in the range μm to mm
  • ]. In this approach, an optimized catalyst was designed by the integration of the catalyst performances at increasing length scales, from the nanoscale (active metal nanoparticles), to the mesoscale (support) and macroscale (reactor). Thus, after identification of the optimal shape and size of PdNP for
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Published 20 Apr 2017

Fluorescent carbon dots from mono- and polysaccharides: synthesis, properties and applications

  • Stephen Hill and
  • M. Carmen Galan

Beilstein J. Org. Chem. 2017, 13, 675–693, doi:10.3762/bjoc.13.67

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  • their in vivo applications are restricted [12]. Therefore, the development of fluorescent nanoparticles that are able to replicate QD fluorescence properties without exhibiting long term toxicity profiles, has become very relevant. The term carbon dots (CDs) has been coined to describe a new class of
  • carbon-based nanomaterials which are typically discrete, quasi-spherical nanoparticles, with sizes usually less than 10 nm in diameter (although bigger sizes have recently been reported). These relatively new nanomaterials have found many applications in the fields of photo- and electrocatalysis
  • : top-down or bottom-up syntheses. Top-down methods are characterised by using a bulk carbon substrate as the starting material; using conditions that remove nanoparticles from the bulk substrate such as electrochemistry, chemical oxidation, arc discharge or laser ablation, carbon-based nanoparticles
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Published 10 Apr 2017

Transition-metal-catalyzed synthesis of phenols and aryl thiols

  • Yajun Liu,
  • Shasha Liu and
  • Yan Xiao

Beilstein J. Org. Chem. 2017, 13, 589–611, doi:10.3762/bjoc.13.58

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  • reaction to proceed smoothly in THF at room temperature (Scheme 4) [24]. The reaction system used CsOH as base, providing phenols in moderate to excellent yields. In 2007, the Diaconescu group described Pd/PANI, which was prepared by supporting palladium nanoparticles with polyaniline (PANI) nanofibers. Pd
  • , the Xu and Feng group cooperatively reported the hydroxylation of aryl halides without ligand using CuI-nanoparticles as catalyst in the presence of (n-Bu)4NBr under very mild conditions [47]. CuI-nanoparticles could be reused with a slight loss of activity. The reaction was carried out in water at 60
  • –80 °C, affording the phenols from aryl iodides and bromides in good to excellent yields (Scheme 23). In the case of aryl bromide, long reaction time (48 h) was required. 110 mol % of CuI-nanoparticles was needed for the complete conversion of aryl bromides bearing electron-donating groups. It's worth
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Published 23 Mar 2017

Novel β-cyclodextrin–eosin conjugates

  • Gábor Benkovics,
  • Damien Afonso,
  • András Darcsi,
  • Szabolcs Béni,
  • Sabrina Conoci,
  • Éva Fenyvesi,
  • Lajos Szente,
  • Milo Malanga and
  • Salvatore Sortino

Beilstein J. Org. Chem. 2017, 13, 543–551, doi:10.3762/bjoc.13.52

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  • plot as well as in the volume plot (see Figure S39 in Supporting Information File 1). The aggregation properties of 4–β-CD were further confirmed by the results obtained by nanoparticles tracking analysis (Figure S40, Supporting Information File 1). The sample, under the selected experimental
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Published 15 Mar 2017

The reductive decyanation reaction: an overview and recent developments

  • Jean-Marc R. Mattalia

Beilstein J. Org. Chem. 2017, 13, 267–284, doi:10.3762/bjoc.13.30

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  • ]. The authors logically proposed that the decyanation occurred via the reduction of an iminium ion intermediate. The hydrogenation of α-aminonitriles catalyzed by nickel nanoparticles results in reductive decyanation and yields 29–31. The colloid solution of nickel is prepared in situ via reduction of
  • reduction by NaH [81]. Reductive decyanation catalyzed by nickel nanoparticles. Yields are given in weight % from GC–MS data [85]. Decyanation of 2-cyanobenzo[b]thiophene [87]. Simplified pathways involved in transition-metal-promoted reductive decyanations [93][95]. Fe-catalyzed reductive decyanation
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Published 13 Feb 2017

Stabilization of nanosized titanium dioxide by cyclodextrin polymers and its photocatalytic effect on the degradation of wastewater pollutants

  • Tamás Zoltán Agócs,
  • István Puskás,
  • Erzsébet Varga,
  • Mónika Molnár and
  • Éva Fenyvesi

Beilstein J. Org. Chem. 2016, 12, 2873–2882, doi:10.3762/bjoc.12.286

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  • thin layer of waste water is treated by solar light to achieve the decomposition of the organic pollutants [32]. Another way of enhancing the surface is the application of nanoparticles (nanoTiO2). Such nanosized particles can readily aggregate forming larger agglomerates of reduced surface and reduced
  • the nanoparticles (with its wider secondary side, Figure 1) [34]. In addition to the improvement of the colloidal stability, also the efficiency of the photocatalytic performance of nanoTiO2 particles can be enhanced by adsorption of β-CD. The latter plays electron-donating and hole-capturing roles
  • dispersions have been studied for degradation of some model organic pollutants (methylene blue and ibuprofen) under UV-A light irradiation. Results and Discussion Selection of the CD derivative for stabilizing nanoTiO2 dispersions In aqueous dispersions, in the presence of salts the nanoparticles of TiO2
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Published 28 Dec 2016

Selective synthesis of thioethers in the presence of a transition-metal-free solid Lewis acid

  • Federica Santoro,
  • Matteo Mariani,
  • Federica Zaccheria,
  • Rinaldo Psaro and
  • Nicoletta Ravasio

Beilstein J. Org. Chem. 2016, 12, 2627–2635, doi:10.3762/bjoc.12.259

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  • a maximum yield of 83% and it can be used only for primary benzylic alcohols. On the contrary Ni nanoparticles act as chemoselective catalysts at room temperature [20]. 1,3,5-Triazo-2,4,6-triphosphorine-2,2,4,4,6,6-hexachloride (TAPC) allows the efficient preparation of thioethers from different
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Published 06 Dec 2016

Tunable microwave-assisted method for the solvent-free and catalyst-free peracetylation of natural products

  • Manuela Oliverio,
  • Paola Costanzo,
  • Monica Nardi,
  • Carla Calandruccio,
  • Raffaele Salerno and
  • Antonio Procopio

Beilstein J. Org. Chem. 2016, 12, 2222–2233, doi:10.3762/bjoc.12.214

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  • heterogeneous or supported catalysts [15][16][17], solid nanopowders or nanoparticles [18][19], non-metal-based heterogeneous acetylation catalysts [20][21][22], as well as natural marine clays instead of homogeneous catalysts as reaction activators [23]. Even if these methods allow a complete peracetylation of
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Published 20 Oct 2016

Ionic liquids as transesterification catalysts: applications for the synthesis of linear and cyclic organic carbonates

  • Maurizio Selva,
  • Alvise Perosa,
  • Sandro Guidi and
  • Lisa Cattelan

Beilstein J. Org. Chem. 2016, 12, 1911–1924, doi:10.3762/bjoc.12.181

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  • ]) dispersed on magnetic mesoporous SiO2/CoFe2O4 and CoFe2O4 nanoparticles [39][40] have been reported as catalysts. In addition, the reaction of ethylene carbonate with methanol for the synthesis of DMC was described in the presence of a mesocellular silica foam (MCF) material [41]. These catalysts are easy
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Published 26 Aug 2016

Cross-linked cyclodextrin-based material for treatment of metals and organic substances present in industrial discharge waters

  • Élise Euvrard,
  • Nadia Morin-Crini,
  • Coline Druart,
  • Justine Bugnet,
  • Bernard Martel,
  • Cesare Cosentino,
  • Virginie Moutarlier and
  • Grégorio Crini

Beilstein J. Org. Chem. 2016, 12, 1826–1838, doi:10.3762/bjoc.12.172

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  • cationic dyes. Zhang et al. [4] studied the removal of cobalt and 1-naphthol onto magnetic nanoparticles containing cyclodextrin and iron and Yang et al. [5] proposed a new nanocomposite adsorbent for the simultaneous removal of organic and inorganic substances from water. Here, we propose to use a single
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Published 12 Aug 2016

Organic chemistry meets polymers, nanoscience, therapeutics and diagnostics

  • Vincent M. Rotello

Beilstein J. Org. Chem. 2016, 12, 1638–1646, doi:10.3762/bjoc.12.161

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  • just starting to move into nanoparticles. As with the polymers, we started off studying the interactions of recognition element-functionalized nanoparticles with monovalent guests – in this case our old friend flavin where we showed modulation of the flavin redox potentials [21]. Taking this research
  • demonstrated this templation with peptides [23] and are (still!) trying to definitively show templation to proteins. As I mentioned above, I am an incessant tinkerer, a trait that has rubbed off on the group. When students mixed complementary versions of the polymers and nanoparticles described above, we were
  • nanocomposite materials, including regular structures using diblock copolymers [25][26] and nanoparticle–protein [27][28] and nanoparticle–nucleic acid composites [29]. Concurrently with our 3D self-assembly, we pursued the use of nanoparticles for surface modification. This research has focused on the use of
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Published 02 Aug 2016

One-pot synthesis of 4′-alkyl-4-cyanobiaryls on the basis of the terephthalonitrile dianion and neutral aromatic nitrile cross-coupling

  • Roman Yu. Peshkov,
  • Elena V. Panteleeva,
  • Wang Chunyan,
  • Evgeny V. Tretyakov and
  • Vitalij D. Shteingarts

Beilstein J. Org. Chem. 2016, 12, 1577–1584, doi:10.3762/bjoc.12.153

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  • being used as components of liquid crystal mixtures [3][4][5][6][7][8], lubricants [9], media for conformational analysis using NMR [10][11][12] and EPR [13] techniques, and nanoparticles-doped liquid crystals [14]. The classic multistage approaches to these compounds, including successive biphenyl
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Published 25 Jul 2016

Towards potential nanoparticle contrast agents: Synthesis of new functionalized PEG bisphosphonates

  • Souad Kachbi-Khelfallah,
  • Maelle Monteil,
  • Margery Cortes-Clerget,
  • Evelyne Migianu-Griffoni,
  • Jean-Luc Pirat,
  • Olivier Gager,
  • Julia Deschamp and
  • Marc Lecouvey

Beilstein J. Org. Chem. 2016, 12, 1366–1371, doi:10.3762/bjoc.12.130

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  • for biomedical imaging applications, the adsorption of plasmatic proteins on the surface of nanoparticles must be prevented to reduce the hepatic capture and increase the plasmatic time life. In biologic media, metal oxide nanoparticles are not stable and must be coated by biocompatible organic
  • the development of superparamagnetic iron oxide nanoparticles (SPIONPs) because of their biocompatibility which allows there in vivo use both for diagnosis in magnetic resonance imaging and in therapy [1][2]. Most often, it is necessary to modify the surface of SPIONPs to increase the metabolic
  • obtain the expected HMBP-PEG-COOH 23 in 85% yield. Conclusion In summary, novel bifunctional PEG-HMBPs ligands for the coating of iron oxide nanoparticles have been synthesized. The procedure is efficient to introduce different functional groups such as azide, carboxylic acid, amine permitting further
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Published 04 Jul 2016

On the mechanism of imine elimination from Fischer tungsten carbene complexes

  • Philipp Veit,
  • Christoph Förster and
  • Katja Heinze

Beilstein J. Org. Chem. 2016, 12, 1322–1333, doi:10.3762/bjoc.12.125

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  • –S24). The appearance of a resonance at δ = 9.68 ppm is assigned to a trace amount of W(CO)5(Z-2). A dark precipitate (possibly tungsten nanoparticles [81][82]) forms during the thermolysis. The half-lives at 60, 70, 80, 90 and 100 °C amount to 145.9, 39.4, 28.9, 16.2 and 12.2 h. The time traces fit to
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Published 27 Jun 2016

Synthesis of a deuterated probe for the confocal Raman microscopy imaging of squalenoyl nanomedicines

  • Eric Buchy,
  • Branko Vukosavljevic,
  • Maike Windbergs,
  • Dunja Sobot,
  • Camille Dejean,
  • Simona Mura,
  • Patrick Couvreur and
  • Didier Desmaële

Beilstein J. Org. Chem. 2016, 12, 1127–1135, doi:10.3762/bjoc.12.109

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  • squalenoyl gemcitabine nanoparticles displayed significant Raman scattering signals. They revealed no differences except from the deuterium peak patterns in the silent spectral region of cells. This paves the way for label-free intracellular trafficking studies of squalenoyl nanomedicines. Keywords
  • triterpene, to a drug led to the formation of a prodrug that spontaneously self-assembled as nanoparticles in water. The advantage of this approach is a very high drug loading into the nanoparticles and the absence of burst release [5]. The proof of concept of this method has been done using gemcitabine (2
  • radioactive labeling 3H,14C has been taken into profit to study the pharmacokinetics, the biodistribution and the metabolism of squalenoyl adenosine nanoparticles [22]. Nevertheless, the synthesis of labeled compounds is chemically challenging, expensive and submitted to drastic regulation rules. In addition
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Published 06 Jun 2016

Stimuli-responsive HBPS-g-PDMAEMA and its application as nanocarrier in loading hydrophobic molecules

  • Yongsheng Chen,
  • Li Wang,
  • Haojie Yu,
  • Zain-Ul-Abdin,
  • Ruoli Sun,
  • Guanghui Jing,
  • Rongbai Tong and
  • Zheng Deng

Beilstein J. Org. Chem. 2016, 12, 939–949, doi:10.3762/bjoc.12.92

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  • blocking hydrophilic PDMAEMA chains on a hydrophobic chain. These amphiphilic polymers may aggregate in water to form nanoparticles having stimuli-responsive properties. Different hydrophobic segments with different microstructures give the aggregates adjustable properties that can be used for various
  • PDI of these two samples sharply decreased below 0.1, which means that the aggregates under these conditions may be uniform. The PDI and the size of nanoparticles used for biomedicine are important. For the human body, the size of these particles should be about 50–200 nm which could be excreted
  • without any toxic effects. Larger nanoparticles may eliminate quickly from human body and smaller nanoparticles may block blood capillaries. In this work, pH 7.4 was similar to the pH of human blood and pH 8.5 was in the range of some secretion. In these pH, HBPS-g-PDMAEMA aggregates showed a narrow
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Published 10 May 2016

Superstructures with cyclodextrins: chemistry and applications III

  • Gerhard Wenz and
  • Eric Monflier

Beilstein J. Org. Chem. 2016, 12, 937–938, doi:10.3762/bjoc.12.91

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  • styrene from ethylbenzene [3][4]. Highly porous networks were synthesized by crosslinking β-CD with tetrafluoroterephthalonitrile. These networks were able to almost completely remove pollutants (e.g., bisphenol A) within a short time from wastewater [5]. Stimuli-responsive nanoparticles were assembled by
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Published 10 May 2016
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