Oligomeric epoxide–amine adducts based on 2-amino-N-isopropylacetamide and α-amino-ε-caprolactam: Solubility in presence of cyclodextrin and curing properties

• Julian Fischer and
• Helmut Ritter

Beilstein J. Org. Chem. 2013, 9, 2803–2811, doi:10.3762/bjoc.9.315

• rate of 1 °C/min. Dynamic light scattering (DLS) experiments were conducted on a Malvern Zetasizer Nano ZS ZEN 3600 at a temperature of 20 °C with a laser wavelength of 633 nm and a detection angle of 173°. The non-negative-least-squares algorithm was used for interpretation. The samples were dissolved

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

• of 1H NMR and IR spectroscopy and by mass spectrometry. Electron microscopy studies and dynamic light scattering measurements show a significant decrease of the derivative size after the complexation with ferrocene. In addition, further evidence for the successful complexation of the end groups was

• , which leads to the formation of the larger structures. Finally, DLS (dynamic light scattering) analysis of 4 and 5 and their complexes with ferrocene were performed. Figure 6 illustrates the hydrodynamic diameters of α-CD-disiloxane 4 and α-CD-disiloxane with ferrocene. The average hydrodynamic diameter

• hydrodynamic diameters of the derivatives and their complexes were determined by use of dynamic light scattering (DLS) in the back scattering mode with a Malvern Zetasizer Nano ZS ZEN3600 at a laser wavelength of 633 nm and a detection angle of 173°. The samples were dissolved in chloroform (10 mg·mL−1) and

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

• repeated centrifugation–redispersion cycles in THF in order to completely remove free polymer chains adsorbed onto the particles. The particles (henceforth SiP–p(VBC) particles) were studied by dynamic light scattering (DLS), which showed a monomodal peak indicating well-defined particles with no

Superstructures of fluorescent cyclodextrin via click-reaction

• Arkadius Maciollek,
• Helmut Ritter and
• Rainer Beckert

Beilstein J. Org. Chem. 2013, 9, 827–831, doi:10.3762/bjoc.9.94

• )-interactions. The supramolecular structures were characterized by 1H NMR-ROESY spectroscopy, dynamic light scattering, UV–vis spectroscopy, fluorescence spectroscopy, and asymmetric flow field-flow fractionation. By adding potassium adamantane-1-carboxylate, the thiazol dye is displaced from the CD-cavity and

• ]. To investigate the expected intermolecular formation of supramolecular structures in aqueous solution, dynamic light scattering (DLS) experiments were performed (Figure 4). Hydrodynamic diameters up to 200 nm indicate the postulated formation of intermolecular complexes. Thus, repeating complexation

• concentration source, the refractive index was used. Calibration of the system was performed with bovine serum albumin. Dynamic light scattering (DLS) experiments were carried out with a Malvern Zetasizer Nano; ZS ZEN 3600 at a temperature of 20 °C. The particle size distribution is derived from a deconvolution

Influence of cyclodextrin on the solubility and the polymerization of (meth)acrylated Triton^® X-100

• Melanie Kemnitz and
• Helmut Ritter

Beilstein J. Org. Chem. 2012, 8, 2176–2183, doi:10.3762/bjoc.8.245

• , matrix-assisted laser desorption ionization mass spectrometry (MALDI-TOF MS), dynamic light scattering (DLS), gel-permeation chromatography (GPC) and turbidity measurements. Additionally, the viscosity change of the methacrylic homopolymer with RAMEB-CD was evaluated. Keywords: (meth)acrylated Triton

New enzymatically polymerized copolymers from 4-tert-butylphenol and 4-ferrocenylphenol and their modification and inclusion complexes with β-cyclodextrin

• Adam Mondrzyk,
• Beate Mondrzik,
• Sabrina Gingter and
• Helmut Ritter

Beilstein J. Org. Chem. 2012, 8, 2118–2123, doi:10.3762/bjoc.8.238

• polystyrene standards in a range of 575 to 3,114,000 g/mol. Toluene was used as the internal standard. Dynamic light scattering (DLS) experiments were carried out with a Malvern Zetasizer Nano ZS ZEN 3600 at a temperature of 20 °C. The particle size distribution was derived from a deconvolution of the

Cyclodextrin-induced host–guest effects of classically prepared poly(NIPAM) bearing azo-dye end groups

• Gero Maatz,
• Arkadius Maciollek and
• Helmut Ritter

Beilstein J. Org. Chem. 2012, 8, 1929–1935, doi:10.3762/bjoc.8.224

• temperatures derived from these experiments were determined at 50% relative transmission. Dynamic light scattering (DLS) experiments were carried out with a Malvern Zetasizer Nano; ZS ZEN 3600 at a temperature of 20 °C. The particle size distribution is derived from a deconvolution of the measured intensity

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

• microscopy (AFM). Size distribution and colloidal suspension stability were characterized by dynamic light scattering (DLS) and sedimentation kinetic studies by using UV–vis spectroscopy. Ferrite binding sites were characterized by zeta potential (ZP) and potentiometric titration. The free volume for both

• response of the cantilever. Dynamic light scattering Fe-Ni/Zn and Fe-Ni/Zn/βCD average hydrodynamic diameter was measured in a Malvern Zetasizer Nano Series ZS particle analyzer, by using polyethylene square cells. All suspensions were prepared by using Milli-Q water before and after the sonication process

Molecular solubilization of fullerene C₆₀ in water by γ-cyclodextrin thioethers

• Hai Ming Wang and
• Gerhard Wenz

Beilstein J. Org. Chem. 2012, 8, 1644–1651, doi:10.3762/bjoc.8.188

• with C60. Particle sizes of C60 were determined by dynamic light scattering. Keywords: C60; cyclodextrins; dynamic light scattering; particle size; solubilization; UV spectrum; Introduction Since the first spectroscopic discovery of buckminsterfullerene, C60, by Kroto, Heath, Curl and Smalley in 1985

• dissolution of C60 by γ-CD thioethers, because they also did not improve the solubilization process significantly. Investigation of aggregation by dynamic light scattering Since aggregation of CDs and CD inclusion compounds was already found in previous work [44][45], dynamic light scattering (DLS

• scattering measurement Particle size distributions of the aqueous solution or dispersions of C60 were determined by dynamic light scattering (DLS) with a ZetaSizer Nano ZS (Malvern Instruments Ltd., Malvern, United Kingdom). From the diffusion coefficient the radius of the particle was determined via the

Influence of cyclodextrin on the solubility of a classically prepared 2-vinylcyclopropane macromonomer in aqueous solution

• Helmut Ritter,
• Jia Cheng and
• Monir Tabatabai

Beilstein J. Org. Chem. 2012, 8, 1528–1535, doi:10.3762/bjoc.8.173

• (TMS) was used to calibrate the δ-scale. Chemical shifts were referenced to the residual solvent peaks (for example δ 2.09 ppm for acetone-d6 and δ 2.22 ppm for D2O). Dynamic light scattering (DLS) measurements were performed on a Malvern high performance particle sizer-extended temperature (HPPS-ET

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

• ), 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

Chiral recognition of ephedrine: Hydrophilic polymers bearing β-cyclodextrin moieties as chiral sensitive host molecules

• Sabrina Gingter and
• Helmut Ritter

Beilstein J. Org. Chem. 2011, 7, 1516–1519, doi:10.3762/bjoc.7.177

• -containing polymer. The supramolecular structures obtained by complexation of ephedrine and cyclodextrin were verified by 2-D ROESY NMR measurements. Dynamic light scattering showed clear differences in the mean coil size. Keywords: chiral recognition; cyclodextrins; ephedrine; host–guest interaction

• -exclusion chromatography (SEC), dynamic light scattering (DLS) and turbidity measurements. To confirm the formation of the proposed host–guest structure of β-cyclodextrin and ephedrine in principle, 2-D ROESY NMR spectroscopy was performed at room temperature with β-CD in excess. Thus the correlation

• diastereomeric effects were expected to influence at least the hydrodynamic diameters of the polymer. Therefore, dynamic light scattering (DLS) measurements of the aqueous solutions were conducted. Indeed, the mean hydrodynamic diameter of polymer 1 extended from 6 nm to 12 nm after complexation of (−)-ephedrine

Hyperbranched polyethylenimine bearing cyclodextrin moieties showing temperature and pH controlled dye release

• Indra Böhm,
• Susanne Katharina Kreth and
• Helmut Ritter

Beilstein J. Org. Chem. 2011, 7, 1130–1134, doi:10.3762/bjoc.7.130

• effectiveness of PEI-CD as drug delivery system in which two different components can be enclosed and released, either separately or simultaneously, in response to different external stimuli. Experimental Measurements: Dynamic Light Scattering (DLS) experiments were carried out with a Malvern Nano ZS ZEN 3600

Chiral recognition of macromolecules with cyclodextrins: pH- and thermosensitive copolymers from N-isopropylacrylamide and N-acryloyl-D/L-phenylalanine and their inclusion complexes with cyclodextrins

• Sabrina Gingter,
• Ella Bezdushna and
• Helmut Ritter

Beilstein J. Org. Chem. 2011, 7, 204–209, doi:10.3762/bjoc.7.27

• of the side groups of copolymers 3D and 3L and their solubility behaviour were investigated by dynamic light scattering and 2D NMR spectroscopy, respectively. Keywords: amino acid; chiral recognition; cyclodextrins; LCST; stimuli-responsive polymers; Introduction Chiral recognition has attracted

• colour as Figure 5 shows. To prove further the influence of complexation of chiral polymers 3D and 3L with chiral RAMEB-CD, we employed dynamic light scattering to measure particle size and hydrodynamic diameters of the supramolecular structures (Figure 6). Evidently, the 3D and 3L copolymers possess

• temperature where the transparency of the solution was 50% of the initial value. The hydrodynamic diameters of the copolymers were determined by dynamic light scattering (DLS) in backscattering mode on a Malvern Zetasizer Nano ZS ZEN 3600 with a laser wavelength of 633 nm and a detection angle of 173

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

• Prussian blue shells were created by adding iron(III) ions to direct miniemulsions of toluene/hexadecane stabilized by the organometallic surfactant [PEG-b-PPG-b-PEG-pentacyano(4-dimethylamino)pyridine) ferrate] [134]. Interparticle coordination was identified by electron microscopy and dynamic light

• scattering experiments. Nanoboxes could be formed when the concentration of surfactant was 4 wt % at a toluene content of 5 wt % [135]. Forty percent of the organometallic surfactant was replaced by PEG-b-PPG-b-PEG terminated by bromine atoms. When more 40% of the organometallic was replaced, the synthesis

Formation of epoxide-amine oligo-adducts as OH-functionalized initiators for the ring-opening polymerization of ε-caprolactone

• Julia Theis and
• Helmut Ritter

Beilstein J. Org. Chem. 2010, 6, 938–944, doi:10.3762/bjoc.6.105

• . The presence of oligomeric compounds was also confirmed by dynamic light scattering (DLS) measurements in dimethylformamide which indicated a number-average hydrodynamic diameter of 1.45 nm. Moreover, the gel permeation chromatography (GPC) diagram (Figure 3) clearly illustrates the formation of

• 1 186 000 Da. Dynamic light scattering (DLS) experiments were implemented on a Malvern HPPS-ET apparatus at a temperature of 25 °C using dimethylformamide (DMF) as solvent. Hellma Suprasil precision cells (110-QS) were used. The particle size distribution was derived from a deconvolution of the

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

• ). The hydrodynamic diameter of the core–shell nano-objects in aqueous dispersion can be detected by dynamic light scattering (DLS). A significant increase of the hydrodynamic diameter can be observed (Table 1), compared to electrostatic stabilized particles, and to CTS functionalized particles with a

Novel multi-responsive P2VP-block-PNIPAAm block copolymers via nitroxide-mediated radical polymerization

• Cathrin Corten,
• Katja Kretschmer and
• Dirk Kuckling

Beilstein J. Org. Chem. 2010, 6, 756–765, doi:10.3762/bjoc.6.89

• aqueous solution, the block copolymers form so called schizophrenic micelles. The hydrodynamic radius Rh of these micelles associated with pH values and temperature was analyzed by dynamic light scattering (DLS). Such kind of block copolymers has potential for many applications, such as controlled drug

• varies with the fraction of protonation of P2VP. Hence, by titration it is not possible to measure the real pKa. In order to investigate the size of the micelles, dynamic light scattering experiments were performed on diluted block copolymer solutions under various conditions. The resulting hydrodynamic

• typical ratio of 1:10:1 (v/v/v, polymer/matrix/salt), and a droplet (1 µL) of the mixture was dried on the target. As calibration standard poly(ethylene oxide) [Mw = 2000 g/mol, Sigma-Aldrich] was used. Dynamic light scattering (DLS) was measured on a Zetasizer Nanoseries Nano-ZS (Malvern instruments

Calix[4]arene-click-cyclodextrin and supramolecular structures with watersoluble NIPAAM-copolymers bearing adamantyl units: “Rings on ring on chain”

• Bernd Garska,
• Monir Tabatabai and
• Helmut Ritter

Beilstein J. Org. Chem. 2010, 6, 784–788, doi:10.3762/bjoc.6.83

• supramolecular complex formation with poly(NIPAAM) bearing attached adamantyl units was investigated by dynamic light scattering (DLS) and turbidity measurements. Keywords: β-cyclodextrin; calix[4]arene; click chemistry; poly(NIPAAM); Introduction Supramolecular interactions of macrocycles with different types

Free radical homopolymerization of a vinylferrocene/cyclodextrin complex in water

• Helmut Ritter,
• Beate E. Mondrzik,
• Matthias Rehahn and
• Markus Gallei

Beilstein J. Org. Chem. 2010, 6, No. 60, doi:10.3762/bjoc.6.60

• water-soluble polymer is obtained due to the host guest interactions. Those polymeric complexes are stable in water up to about 90 °C. Above this temperature the polymer precipitates due to decomplexation. The complex was investigated by 1H NMR spectrometry, dynamic light scattering (DLS), differential

• /ionization-time-of-flight mass spectrometry (MALDITOF-MS) was performed on a Bruker Ultraflex TOF mass spectrometer. Cyclic voltammetry measurements were performed on a simplot instrument with a resolution of <100 pA. Dynamic light scattering (DLS) experiments were carried out with a Malvern HPPS-ET at 25 °C

• -H), 3.86 (20 H, 4-H), 4.25–3.96 (9 H, 7-H), 4.71–5.20 (21H, 10-H), 6.18 (1H, 6-H), 7.20 (20H, 5-H); MALDI-TOF 7: m/z 1.6 × 104. Dynamic light scattering of methyl-β-CD 2 (solid line), vinylferrocene 1 complexed with methyl-β-CD (dashed line) and complexed polyvinylferrocene 3 (dotted line). The

New amphiphilic glycopolymers by click functionalization of random copolymers – application to the colloidal stabilisation of polymer nanoparticles and their interaction with concanavalin A lectin

• Otman Otman,
• Paul Boullanger,
• Eric Drockenmuller and
• Thierry Hamaide

Beilstein J. Org. Chem. 2010, 6, No. 58, doi:10.3762/bjoc.6.58

• Pluronic® F-68. The mannose moieties are accessible at the surface of nanoparticles and available for molecular recognition by concanavalin A lectin. Interaction of mannose units with the lectin were evaluated by measuring the changes in nanoparticles size by dynamic light scattering in dilute media

• . Keywords: click chemistry; con A lectin; dynamic light scattering; glycopolymer; polymer nanoparticles; Introduction Over the last decades, research efforts in pharmaceutical, food and cosmetics technologies have been directed not only towards the syntheses of new bioactive entities or medicines, but also

• nanoparticles were measured by dynamic light scattering (each measurement was repeated five times) at 25 °C with a Malvern Zetasizer 1000HSa series (wavelength 633.0 nm, RI (dispersant) 1.330, angle 90°); data treatments were made in intensity, with water viscosity 0.89 cP. Interaction of the nanoparticles