Search results

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

Supported bifunctional thioureas as recoverable and reusable catalysts for enantioselective nitro-Michael reactions

  • José M. Andrés,
  • Miriam Ceballos,
  • Alicia Maestro,
  • Isabel Sanz and
  • Rafael Pedrosa

Beilstein J. Org. Chem. 2016, 12, 628–635, doi:10.3762/bjoc.12.61

Graphical Abstract
  • nanoparticles [10][11][12], inorganic solids [13][14], and different polystyrene derivatives [15][16][17][18][19][20]. Bifunctional thioureas were first supported on PEG [21], and later on different materials such as poly(methylhydrosiloxane) [16], polystyrene [18][19][20][21][22], and magnetic nanoparticles
PDF
Album
Supp Info
Full Research Paper
Published 01 Apr 2016

Optimized methods for preparation of 6I-(ω-sulfanyl-alkylene-sulfanyl)-β-cyclodextrin derivatives

  • Eva Bednářová,
  • Simona Hybelbauerová and
  • Jindřich Jindřich

Beilstein J. Org. Chem. 2016, 12, 349–352, doi:10.3762/bjoc.12.38

Graphical Abstract
  • solid surfaces by CDs. Among the solid surfaces, to which CDs were attached, are sorbents for separation techniques or waste water treatment [8] or nanoparticles [6]. In our work, we focused on the preparation of sulfanyl-group-containing CD derivatives – 6I-deoxy-6I-(ω-sulfanyl-alkylene-sulfanyl)-β
PDF
Album
Supp Info
Full Research Paper
Published 24 Feb 2016

Enabling technologies and green processes in cyclodextrin chemistry

  • Giancarlo Cravotto,
  • Marina Caporaso,
  • Laszlo Jicsinszky and
  • Katia Martina

Beilstein J. Org. Chem. 2016, 12, 278–294, doi:10.3762/bjoc.12.30

Graphical Abstract
  • 2006 Lipshutz et al. demonstrated that the impregnation of charcoal with an aqueous solution of Cu(NO3)2 in US bath, gave copper nanoparticles: an efficient catalyst in CuAAC [58]. Besides the easier work-up of heterogeneous catalysis, Cu(I)/charcoal also gave a higher yield compared to soluble CuSO4
  • ferromagnetic materials by grinding under less-environmentally friendly conditions in this case. The components were prepared using classic methods and the final composite was obtained by ball milling of arc-melted MnBi particles and Fe-Co nanoparticles prepared with the aid of a β-CD/oleic acid complex. The
PDF
Album
Review
Published 15 Feb 2016

Highly stable and reusable immobilized formate dehydrogenases: Promising biocatalysts for in situ regeneration of NADH

  • Barış Binay,
  • Dilek Alagöz,
  • Deniz Yildirim,
  • Ayhan Çelik and
  • S. Seyhan Tükel

Beilstein J. Org. Chem. 2016, 12, 271–277, doi:10.3762/bjoc.12.29

Graphical Abstract
  • ] reported the optimal pH values were 7.0 for both free FDH and immobilized FDH onto polydopamine-coated iron oxide nanoparticles (PD-IONPs). The optimum pH values of the both free Pseudomonas sp. 101 FDH and its immobilized form onto glyoxylagarose were reported as 7.0 [16]. The temperature–activity
  • quite different depending on the used immobilization procedure. The optimum temperature of C. boidinii FDH immobilized onto magnetite nanoparticles silanized with (3-aminopropyl)triethoxysilane was 42 °C whereas the optimum temperature was 27 °C when this support was further coated with glyoxylagarose
PDF
Album
Full Research Paper
Published 12 Feb 2016

Aggregation behavior of amphiphilic cyclodextrins in a nonpolar solvent: evidence of large-scale structures by atomistic molecular dynamics simulations and solution studies

  • Giuseppina Raffaini,
  • Fabio Ganazzoli and
  • Antonino Mazzaglia

Beilstein J. Org. Chem. 2016, 12, 73–80, doi:10.3762/bjoc.12.8

Graphical Abstract
  • nanoaggregates even in apolar solvents. Keywords: aggregation; amphiphilic cyclodextrins; molecular dynamics; nanoparticles; self-assembly; simulations; Introduction Amphiphilic cyclodextrins (aCD) are a class of molecules highly investigated for their self-assembly properties and inherent potential
PDF
Album
Full Research Paper
Published 14 Jan 2016

Effective immobilisation of a metathesis catalyst bearing an ammonium-tagged NHC ligand on various solid supports

  • Krzysztof Skowerski,
  • Jacek Białecki,
  • Stefan J. Czarnocki,
  • Karolina Żukowska and
  • Karol Grela

Beilstein J. Org. Chem. 2016, 12, 5–15, doi:10.3762/bjoc.12.2

Graphical Abstract
  • to the solution. A different valuable concept is the covalent or electrostatic immobilisation of ruthenium initiators on magnetically active nanoparticles. Complexes 5 [37] and 6 [38] presented in Figure 1 can serve as an examples, but others were also prepared [39]. These compounds are carefully
  • endeavour aimed at getting a broader perspective. Immobilisation of 8 on iron powder First, we attempted to prepare a model for a magnetically separable catalyst [55]. This idea has been explored previously by attaching tagged Ru complexes to specially designed magnetically active nanoparticles. We wondered
  • order to provide fully Fe-supported complex 8. This method for the preparation of a magnetically removable catalyst is obviously less complicated than the reported syntheses of catalysts on magnetic nanoparticles [37][38][39]. The main difference is that the latter materials are much more
PDF
Album
Supp Info
Full Research Paper
Published 05 Jan 2016

Physical properties and biological activities of hesperetin and naringenin in complex with methylated β-cyclodextrin

  • Waratchada Sangpheak,
  • Jintawee Kicuntod,
  • Roswitha Schuster,
  • Thanyada Rungrotmongkol,
  • Peter Wolschann,
  • Nawee Kungwan,
  • Helmut Viernstein,
  • Monika Mueller and
  • Piamsook Pongsawasdi

Beilstein J. Org. Chem. 2015, 11, 2763–2773, doi:10.3762/bjoc.11.297

Graphical Abstract
  • -loaded nanoparticles which exhibited significant cytotoxicity at high concentrations (30, 40 and 50 μg/mL) [59]. At low concentration (0.025 mM), naringenin complexed with DM-β-CD exerted a higher effect on MCF-7 and HeLa cells than free naringenin. However, for CaCo-2 cells, the effect of the naringenin
PDF
Album
Supp Info
Full Research Paper
Published 29 Dec 2015

Recent advances in metathesis-derived polymers containing transition metals in the side chain

  • Ileana Dragutan,
  • Valerian Dragutan,
  • Bogdan C. Simionescu,
  • Albert Demonceau and
  • Helmut Fischer

Beilstein J. Org. Chem. 2015, 11, 2747–2762, doi:10.3762/bjoc.11.296

Graphical Abstract
  • 4 with ferricenium hexafluorophosphate led to a stable biferrocenium polymer while oxidation with Au(III) or Ag(I) allowed the formation of networks with nanosnake morphology, consisting of mixed-valent Fe(II)–Fe(III) polymers that encapsulate metal (Au or Ag) nanoparticles (NPs). These polymers
  • biferrocenium motifs recommends them for designing new redox reactions, eventually leading to value-added nanomaterials. Along a different line, in a recent, inventive work Astruc and coworkers [48] demonstrated that triazolylbiferrocenyl-containing polymers can effectively stabilize palladium nanoparticles
  • = BPh4 or Cl). Self-assembly of these block copolymers into core–shell spherical micelles was successfully conducted and, by UV/ozonolysis or thermal pyrolysis generating antiferromagnetic CoO species, some of these micelles could be converted into inorganic nanoparticles. With the aim at extending the
PDF
Album
Review
Published 28 Dec 2015

Pyridylidene ligand facilitates gold-catalyzed oxidative C–H arylation of heterocycles

  • Kazuhiro Hata,
  • Hideto Ito,
  • Yasutomo Segawa and
  • Kenichiro Itami

Beilstein J. Org. Chem. 2015, 11, 2737–2746, doi:10.3762/bjoc.11.295

Graphical Abstract
  • elimination steps, we believe that the strongly electron-donating PyC not only facilitates gold(I)-to-gold(III) oxidation in catalysis but also prolongs the catalyst lifetime by preventing the ligand dissociation and formation of inactive gold nanoparticles. Conclusion In summary, we have developed the
PDF
Album
Supp Info
Full Research Paper
Published 28 Dec 2015

Synthesis of bi- and bis-1,2,3-triazoles by copper-catalyzed Huisgen cycloaddition: A family of valuable products by click chemistry

  • Zhan-Jiang Zheng,
  • Ding Wang,
  • Zheng Xu and
  • Li-Wen Xu

Beilstein J. Org. Chem. 2015, 11, 2557–2576, doi:10.3762/bjoc.11.276

Graphical Abstract
  • , powder or nanoparticles) in the presence or absence of Cu(II) in aqueous media also provides the key active Cu(I) in some CuAAC reactions. As an important supplement to the classic Huisgen cycloaddition promoted by copper catalysis, this review will deal with the copper-catalyzed syntheses of bi- and
PDF
Album
Review
Published 11 Dec 2015

Smart molecules for imaging, sensing and health (SMITH)

  • Bradley D. Smith

Beilstein J. Org. Chem. 2015, 11, 2540–2548, doi:10.3762/bjoc.11.274

Graphical Abstract
  • ]. Nanoparticles containing these self-illuminating molecules enable high sensitivity imaging of deep-tissue target sites in living subjects [40]. A recent spin-off from the squaraine rotaxane project uses homologous croconaine dyes to absorb 800 nm laser light and cleanly convert the energy into heat without
  • producing reactive singlet oxygen [41][42][43]. The dyes enable new types of nanoscale heating technologies that release sensitive payload such as dyes, drugs, oligonucleotides, or proteins. The dyes can also be loaded into nanoparticles for anticancer photothermal therapy in preclinical animal models
PDF
Album
Review
Published 10 Dec 2015

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

Graphical Abstract
  • molecules or by dispersion interactions at their lateral surface. We suggest that these aggregates can also form the nucleation stage of larger systems as well as the building blocks of micelles, vesicle, membranes, or generally nanoparticles thus opening new perspectives in the design of aggregates
  • correlating their structures with the pharmaceutical properties. Keywords: aggregation; amphiphilic cyclodextrins; micelles; molecular dynamics simulations; nanoparticles; self-assembly; Introduction Inclusion complexes with supramolecular structures formed by native or modified cyclodextrins (CDs) are
PDF
Album
Supp Info
Full Research Paper
Published 07 Dec 2015

Size-controlled and redox-responsive supramolecular nanoparticles

  • Raquel Mejia-Ariza,
  • Gavin A. Kronig and
  • Jurriaan Huskens

Beilstein J. Org. Chem. 2015, 11, 2388–2399, doi:10.3762/bjoc.11.260

Graphical Abstract
  • Raquel Mejia-Ariza Gavin A. Kronig Jurriaan Huskens Molecular NanoFabrication group, MESA+ Institute for Nanotechnology University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands 10.3762/bjoc.11.260 Abstract Control over the assembly and disassembly of nanoparticles is pivotal for
  • their use as drug delivery vehicles. Here, we aim to form supramolecular nanoparticles (SNPs) by combining advantages of the reversible assembly properties of SNPs using host–guest interactions and of a stimulus-responsive moiety. The SNPs are composed of a core of positively charged poly(ethylene imine
  • core of the SNPs. Keywords: host–guest interactions; nanoparticles; self-assembly; stimulus-responsive; supramolecular chemistry; Introduction Self-assembly and molecular recognition are two core concepts underlying supramolecular chemistry. These offer convenient and versatile pathways to
PDF
Album
Full Research Paper
Published 01 Dec 2015

Biocatalysis for the application of CO2 as a chemical feedstock

  • Apostolos Alissandratos and
  • Christopher J. Easton

Beilstein J. Org. Chem. 2015, 11, 2370–2387, doi:10.3762/bjoc.11.259

Graphical Abstract
  • of CO2 to CO through in vitro application of CODH has been of interest as the enzymatic product may be further converted into hydrocarbons through the Fischer–Tropsch process [146]. In work carried out by Armstrong, Ragsdale and coworkers [147][148], metal oxide nanoparticles were functionalised with
PDF
Album
Review
Published 01 Dec 2015

Preparation of Pickering emulsions through interfacial adsorption by soft cyclodextrin nanogels

  • Shintaro Kawano,
  • Toshiyuki Kida,
  • Mitsuru Akashi,
  • Hirofumi Sato,
  • Motohiro Shizuma and
  • Daisuke Ono

Beilstein J. Org. Chem. 2015, 11, 2355–2364, doi:10.3762/bjoc.11.257

Graphical Abstract
  • on the type of oil solvent. Our research focuses on a new class of Pickering emulsifiers based on nanometer-sized hydrogel nanoparticles composed of crosslinked CD polymers (hereafter CD nanogels), which have a surface-active property and form stable emulsions at the oil-water interface. Reports on
  • CD polymer, which can be dispersed in water as well as in nonpolar solvents. This amphiphilic polymer should realize water-swellable hydrogel nanoparticles containing CDs (CD nanogels). In this paper, we describe the preparation of Pickering emulsions using CD nanogels composed of crosslinked DM-β-CD
  • the oil droplets from coalescence. Conclusion Amphiphilic CD nanogels, which are a new class of soft hydrogel nanoparticles, were prepared by crosslinking DM-β-CDs with PDI followed by the immersion in water. The DLS study shows that the primary CD nanogels (30–50 nm in diameter) assemble into larger
PDF
Album
Supp Info
Full Research Paper
Published 30 Nov 2015

Cu(I)-catalyzed N,N’-diarylation of natural diamines and polyamines with aryl iodides

  • Svetlana P. Panchenko,
  • Alexei D. Averin,
  • Maksim V. Anokhin,
  • Olga A. Maloshitskaya and
  • Irina P. Beletskaya

Beilstein J. Org. Chem. 2015, 11, 2297–2305, doi:10.3762/bjoc.11.250

Graphical Abstract
  • -aryldiamines using aryl iodides in the presence of CuCl under neat conditions [28], N,N’-diarylation of the simplest propane-1,3-diamine and butane-1,4-diamine was carried out using a CuI-metformin catalyst [29], monoarylation of mono- and diamines was studied using Cu2O and CuO nanoparticles and CuO
PDF
Album
Supp Info
Full Research Paper
Published 24 Nov 2015

Synthesis, structure, and mechanical properties of silica nanocomposite polyrotaxane gels

  • Kazuaki Kato,
  • Daisuke Matsui,
  • Koichi Mayumi and
  • Kohzo Ito

Beilstein J. Org. Chem. 2015, 11, 2194–2201, doi:10.3762/bjoc.11.238

Graphical Abstract
  • by a novel network formed using cyclodextrin-based polyrotaxanes. Covalent bond formation between the cyclic components of polyrotaxanes and the surface of silica nanoparticles (15 nm diameter) resulted in an infinite network structure without direct bonds between the main chain polymer and the
  • silica. Small-angle X-ray scattering revealed that the homogeneous distribution of silica nanoparticles in solution was maintained in the gel state. Such homogeneous nanocomposite gels were obtained with at least 30 wt % silica content, and the Young’s modulus increased with silica content. Gelation did
  • not occur without silica. This suggests that the silica nanoparticles behave as cross-linkers. Viscoelastic measurements of the nanocomposite gels showed no stress relaxation regardless of the silica content for <20% compression strain, indicating an infinite stable network without physical cross
PDF
Album
Full Research Paper
Published 16 Nov 2015

Effective ascorbate-free and photolatent click reactions in water using a photoreducible copper(II)-ethylenediamine precatalyst

  • Redouane Beniazza,
  • Natalia Bayo,
  • Florian Molton,
  • Carole Duboc,
  • Stéphane Massip,
  • Nathan McClenaghan,
  • Dominique Lastécouères and
  • Jean-Marc Vincent

Beilstein J. Org. Chem. 2015, 11, 1950–1959, doi:10.3762/bjoc.11.211

Graphical Abstract
  • -reduction processes leading to the formation of copper(0) nanoparticles occurred when prolonged irradiation times were applied [12][13]. When a deaerated solution of 1 in THF was irradiated at 365 nm, a very fast change of the solution aspect was observed, the solution becoming colourless in ≈10 min as
PDF
Album
Supp Info
Full Research Paper
Published 21 Oct 2015

Preparative semiconductor photoredox catalysis: An emerging theme in organic synthesis

  • David W. Manley and
  • John C. Walton

Beilstein J. Org. Chem. 2015, 11, 1570–1582, doi:10.3762/bjoc.11.173

Graphical Abstract
  • series of two electron reductions. The scope of reductive photoredox applications was significantly boosted by Scaiano and co-workers’ discovery that organic halides function as acceptors with platinized TiO2 nanoparticles [71]. They used (iPr)2NEt as the sacrificial donor and demonstrated that reductive
PDF
Album
Review
Published 09 Sep 2015

The synthesis of active pharmaceutical ingredients (APIs) using continuous flow chemistry

  • Marcus Baumann and
  • Ian R. Baxendale

Beilstein J. Org. Chem. 2015, 11, 1194–1219, doi:10.3762/bjoc.11.134

Graphical Abstract
  • scenario magnetic or conductive materials (metal beads, nanoparticles, etc.) are placed within a reactor cartridge exposed to an oscillating magnetic field of medium (15–25 kHz) or high frequency (780–850 kHz) leading to very rapid heating of reagent streams pumped through the reactor. A powerful
PDF
Album
Review
Published 17 Jul 2015

Influence of length and flexibility of spacers on the binding affinity of divalent ligands

  • Susanne Liese and
  • Roland R. Netz

Beilstein J. Org. Chem. 2015, 11, 804–816, doi:10.3762/bjoc.11.90

Graphical Abstract
  • overwhelming variety of multivalent ligand architectures that range from small divalent ligands to densely packed nanoparticles, led to different approaches to describe multivalency, depending on the size and valency of the system. Several studies aimed to treat ligand–receptor systems with different
PDF
Album
Supp Info
Full Research Paper
Published 15 May 2015

Impact of multivalent charge presentation on peptide–nanoparticle aggregation

  • Daniel Schöne,
  • Boris Schade,
  • Christoph Böttcher and
  • Beate Koksch

Beilstein J. Org. Chem. 2015, 11, 792–803, doi:10.3762/bjoc.11.89

Graphical Abstract
  • macrostructures. Keywords: coiled-coil peptides; α-helical fibrils; controlled aggregation; gold nanoparticles; multivalency; Introduction In the past few decades metal and semiconductor nanoparticles, including gold nanoparticles, have gained much interest due to their desirable optical, magnetic, and
  • electronic properties [1]. In particular, the distinct colour of gold nanoparticles is a result of the localised surface plasmon resonance (LSPR) band caused by collective electron oscillations. The LSPR induces a certain excitation band at visible wavelengths in the absorption spectrum, the position and
  • width of which is highly dependent upon nanoparticle size. However, nanoparticle aggregation induces a spectral red-shift and broadening of the band in the absorption spectrum which depends on the distance between nanoparticles, the density of the assembly and the size of the particles [2][3]. Thus the
PDF
Album
Supp Info
Full Research Paper
Published 15 May 2015

Multivalent dendritic polyglycerolamine with arginine and histidine end groups for efficient siRNA transfection

  • Fatemeh Sheikhi Mehrabadi,
  • Hanxiang Zeng,
  • Mark Johnson,
  • Cathleen Schlesener,
  • Zhibin Guan and
  • Rainer Haag

Beilstein J. Org. Chem. 2015, 11, 763–772, doi:10.3762/bjoc.11.86

Graphical Abstract
  • dynamic light scattering (DLS). Figure 2 shows the size distribution of dPG polyplexes (at N/P ratio 10). The average size of all nanoparticles ranges from 60–100 nm. In general, the AAdPG/siRNA polyplexes were smaller than the corresponding dPG-NH2 50%/siRNA polyplexes. Moreover, AAdPG complexes have a
  • broader distribution of the final nanoparticles. The size of dPG-13Arg and dPG-13His complexes was slightly smaller than the other dPG-based vectors. The surface charge of the final nanoparticles was comparable to the corresponding complexes of siRNA and dPG-NH2 50% with terminal primary amines and about
PDF
Album
Supp Info
Full Research Paper
Published 13 May 2015

Glycodendrimers: tools to explore multivalent galectin-1 interactions

  • Jonathan M. Cousin and
  • Mary J. Cloninger

Beilstein J. Org. Chem. 2015, 11, 739–747, doi:10.3762/bjoc.11.84

Graphical Abstract
  • mediated interactions. Dynamic light scattering and fluorescence microscopy were used to study the multivalent interaction of galectin-1 with the glycodendrimers in solution, and glycodendrimers were observed to organize galectin-1 into nanoparticles. In the presence of a large excess of galectin-1
  • , glycodendrimers nucleated galectin-1 into nanoparticles that were remarkably homologous in size (400–500 nm). To understand augmentation of oncologic cellular aggregation by galectin-1, glycodendrimers were used in cell-based assays with human prostate carcinoma cells (DU145). The results revealed that
  • glycodendrimers would organize extracellular galectin-1 into aggregates that would influence the biological activity of galectin-1. To test this hypothesis, lactose functionalized dendrimers were used to nucleate the aggregation of galectin-1 into nanoparticles, and the sizes of the galectin-1/glycodendrimer
PDF
Album
Supp Info
Full Research Paper
Published 12 May 2015

Probing multivalency in ligand–receptor-mediated adhesion of soft, biomimetic interfaces

  • Stephan Schmidt,
  • Hanqing Wang,
  • Daniel Pussak,
  • Simone Mosca and
  • Laura Hartmann

Beilstein J. Org. Chem. 2015, 11, 720–729, doi:10.3762/bjoc.11.82

Graphical Abstract
  • , because a potentially multivalent arrangement of mannose on AA and CA grafting units could lead to chelate- or subsite binding at the ConA receptor enhancing the affinity of individual mannose units. In contrast to other work on similar multivalent scaffolds like oligomers, dendrimers or nanoparticles [20
PDF
Album
Supp Info
Full Research Paper
Published 12 May 2015
Other Beilstein-Institut Open Science Activities