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

• in the liquid phase, covering the main contributions appeared in the literature from 1997 up to August 2016. Some aspects of the topic have been surveyed in the past [28][29]. Details of alkyne hydrogenation reactions in general, including mechanism [30][31], kinetics [32][33], adsorption phenomena

• . Selectivity in partial hydrogenation is ruled by the relative rates of the first and second hydrogenation steps, as well as by the adsorption strengths of alkyne and alkene over the metal catalyst surface. Other side-products may include those due to dimerization and isomerization reactions, depending on the

• adsorption on the atomically dispersed Pd sites. Electrostatic stabilization of Pd atoms was ascribed to a strong interaction with the nitrogen-coordinating species on the basis of DFT calculations. Effective stabilization also prevented site aggregation, resulting in pretty constant catalytic activity over

Sulfamide chemistry applied to the functionalization of self-assembled monolayers on gold surfaces

• Loïc Pantaine,
• Vincent Humblot,
• Vincent Coeffard and
• Anne Vallée

Beilstein J. Org. Chem. 2017, 13, 648–658, doi:10.3762/bjoc.13.64

• interest in the past decades because of their potential applications in various areas such as biomaterials, tissue engineering, biosensors and electronics [1][2][3]. The seminal work of Nuzzo and Allara on the adsorption of disulfides on gold surface has triggered numerous research activities in the

• after the different reaction steps. The values presented in Figure 1 display water contact angles for bare Au around 67 ± 2° as expected for a clean gold surface [41]. Upon 4-ATP adsorption the water contact angle decreases compared to the clean gold sample with a value of 54 ± 2° indicating the

• Table 1. The general spectroscopic profiles in two different states are comparable, which suggests the successful adsorption of the sulfamide 1 on the gold surface. There is quite a good agreement between both spectra, and the differences observed can be explained by the specificity of both IR

Adsorption of RNA on mineral surfaces and mineral precipitates

• Elisa Biondi,
• Yoshihiro Furukawa,
• Jun Kawai and
• Steven A. Benner

Beilstein J. Org. Chem. 2017, 13, 393–404, doi:10.3762/bjoc.13.42

• aragonite. These have relevance to the prebiotic stabilization of RNA, where such carbonate minerals are expected to have been abundant, as they appear to be today on Mars. Keywords: carbonates; natural minerals; origins of life; RNA adsorption; synthetic minerals; Introduction It has been nearly 70 years

• surfaces offer the opportunity to concentrate relevant species from dilute aqueous environments, perhaps without unproductive intermolecular reactions. Such adsorption as a concentration mechanism offers an alternative to evaporation in a desert environment. Mineral adsorption from a large ocean is an

• . Adsorption of these onto mineral surfaces has been shown to slow that destruction [9], in some cases without greatly damaging the catalytic activity of those pre-biopolymers [10], in other cases with evolution [11]. As Hazen and Sverjensky remark [12], mineral environments are far more complex than the

Extrusion – back to the future: Using an established technique to reform automated chemical synthesis

• Deborah E. Crawford

Beilstein J. Org. Chem. 2017, 13, 65–75, doi:10.3762/bjoc.13.9

• ]. There is a lot of commercial interest into the use of MOFs for gas capture and chemical separations [46]. Recently, the first commercial use of MOFs has been reported and this involves the adsorption of ethylene gas from the ripening of fruit and vegetables postharvest [47]. As the commercial interest

Diastereoselective anodic hetero- and homo-coupling of menthol-, 8-methylmenthol- and 8-phenylmenthol-2-alkylmalonates

• Matthias C. Letzel,
• Hans J. Schäfer and
• Roland Fröhlich

Beilstein J. Org. Chem. 2017, 13, 33–42, doi:10.3762/bjoc.13.5

• ]. This finding points to a free radical or its reversible adsorption at the electrode. However, the latter pathway was ruled out by experiments of Utley et al. [48][49], when comparing the coupling of unsaturated and saturated carboxylic acids and the effect of adsorption. Ester 30a has been cleaved with

Supramolecular frameworks based on [60]fullerene hexakisadducts

• Andreas Kraft,
• Johannes Stangl,
• Ana-Maria Krause,
• Klaus Müller-Buschbaum and
• Florian Beuerle

Beilstein J. Org. Chem. 2017, 13, 1–9, doi:10.3762/bjoc.13.1

• °C. Sorption properties were determined for N2 and Ar gas adsorption via a BET study at 77 K. Therein, the framework shows Henry behavior and no microporosity with a surface area of 40 m2 g−1 for N2 and only 18 m2 g−1 for Ar (see Figure S14 in Supporting Information File 1). However, the measured N2

• Schönfeld (Quantachrome) for discussion on the adsorption behavior. Financal support by the Fonds der Chemischen Industrie (Liebig fellowship for FB), the DFG (SPP 1362/2 “Porous MOFs”, BE 4808/ 1-2 and MU 1562/5-2) as well as the Bavarian Ministry of Science, Research and the Arts (Collaboratory Research

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

• 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

• as low concentration as 1% CMBCD-P and the turbidity remained <105% within 120 min of observation (Table 2). The stabilizing effect of the CD-based polymers especially of CMBCD-P can be attributed to steric effects caused by the adsorption of the polymer on the surface of nanoTiO2 particles. It forms

• solution the rate of decomposition was lower partly attributed to adsorption of chloride on TiO2 surface. There might be a competition between dyes and anions for the adsorption sites and the anions may modify the superficial properties of TiO2 [44]. The total concentration of inorganic ions in tap water

Electron-transfer-initiated benzoin- and Stetter-like reactions in packed-bed reactors for process intensification

• Anna Zaghi,
• Daniele Ragno,
• Graziano Di Carmine,
• Carmela De Risi,
• Olga Bortolini,
• Pier Paolo Giovannini,
• Giancarlo Fantin and
• Alessandro Massi

Beilstein J. Org. Chem. 2016, 12, 2719–2730, doi:10.3762/bjoc.12.268

• previous study on the benzoin condensation, the Stetter-like reaction of benzil (1a, 0.1 M) with chalcone 9a (0.05 M) was optimized at 70 °C with a flow rate of 5 μL min−1 (Table 5, entry 1). Because of the partial adsorption of the target 1,4-diketone 10aa onto the basic packing material 5, the reactor R5

Synthesis of three-dimensional porous hyper-crosslinked polymers via thiol–yne reaction

• Mathias Lang,
• Alexandra Schade and
• Stefan Bräse

Beilstein J. Org. Chem. 2016, 12, 2570–2576, doi:10.3762/bjoc.12.252

• . Furthermore, adsorption measurements of HCPs 3 and 5 were carried out with nitrogen gas at 77 K after pre-drying for 16 h at 80 °C in vacuum. Both HCPs showed BET-surface areas >400 m2/g and the values of the specific surface area and cumulative volumes of the HCPs are collected in Table 2. The corresponding

• adsorption isotherms are depicted in Figure 4. The strong slope of the isotherms at low relative pressures indicates a permanent porous character of the materials. Also the step around p/p0 = 0.5 at desorption isotherms (Supporting Information File 1, Figures S1 and S2) indicates the mesoporous character of

• -ray diffraction (PXRD) and adsorption measurements using nitrogen at 77 K. IR-spectra of tetrathiol 2 (blue), tetraalkyne 1 (red) and HCP 3 (black). IR-spectra of tetrathiol 2 (blue), hexaalkyne 4 (red) and HCP 3 (black). SEM images of HCP 3 (left) and HCP 5 (right). Adsorption isotherms of HCP 3

Robust C–C bonded porous networks with chemically designed functionalities for improved CO₂ capture from flue gas

• Damien Thirion,
• Joo S. Lee,
• Ercan Özdemir and
• Cafer T. Yavuz

Beilstein J. Org. Chem. 2016, 12, 2274–2279, doi:10.3762/bjoc.12.220

• important pore sizes (2.2, 3.0, 5.0, 7.0 nm). Larger pores are required for post-modification, as the reagents may not be able to penetrate to the small micropores. CO2 sorption isotherms reflect the physisorptive nature of COP-156 with almost no hysteresis and an isosteric heat of adsorption (Qst) of 28.1

• cm−1), which loses intensity by the post-modification reactions. Gas adsorption (filled dots)-desorption (empty dots) isotherms and pore size distribution of COP-156 (black), COP-156-amine (blue) and COP-156-amidoxime (red). CO2 uptake under moist conditions at 40 °C of COP-156 (black) and COP-156

• -amine (blue). Synthesis route for COP-156 and COP-157, and the post-modification of COP-156. BET surface area, CO2 sorption properties at 273 K, 298 K and heat of adsorption values of all networks. Supporting Information Supporting Information File 388: Materials and methods, synthesis, FTIR spectra

Hydroxy-functionalized hyper-cross-linked ultra-microporous organic polymers for selective CO₂ capture at room temperature

• Partha Samanta,
• Priyanshu Chandra and
• Sujit K. Ghosh

Beilstein J. Org. Chem. 2016, 12, 1981–1986, doi:10.3762/bjoc.12.185

• , H2 and O2 at room temperature. A high isosteric heat of adsorption (Qst) has been obtained for both materials because of strong interactions between polar –OH groups and CO2 molecules. Keywords: carbon dioxide capture; hyper-cross-linked polymer; metal-organic framework; microporous organic polymer

• temperatures (273 K and 298 K) gas (CO2, N2, H2 and O2) adsorption experiments were carried out for both compounds. HCP-91 and HCP-94 showed selective CO2 capture at both temperatures over other flue gases. Results and Discussion For the synthesis of HCP-91 and HCP-94, we used 4-phenylphenol and 9

• , a clear capsule-type of morphology was found in the FESEM (Figure 2d and Figure S6). After all characterizations and proper desolvation of both compounds, we investigated their porosity. First, we measured the N2 adsorption at 77 K. The N2 uptake for HCP-91 was found to be 595 mL/g, whereas that for

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

• hydrocarbons (PAH) and three alkylphenols (AP), the material exhibited high adsorption capacities: >99% of Co2+, Ni2+ and Zn2+ were removed, between 65 and 82% of the PAHs, as well as 69 to 90% of the APs. Due to the structure of the polymer and its specific characteristics, such as the presence of carboxylic

• groups and CD cavities, the adsorption mechanism involves four main interactions: ion exchange, electrostatic interactions and precipitation for metal removal, and inclusion complexes for organics removal. In industrial discharge waters, competition effects appeared, especially because of the presence of

• calcium at high concentrations, which competed with other pollutants for the adsorption sites of the adsorbent. Keywords: alkylphenols; adsorption; cyclodextrin; metals; polycyclic aromatic hydrocarbons; Introduction Although considerable efforts have been made by the industrial sector over the last 30

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

• 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

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

• using multi-point attachment strategies [18][19][20]. The immobilization mechanism of enzymes is based on the hydrophobic adsorption of enzymes onto the supports and then the covalent immobilization of enzymes. Besides, these supports are easily modified to generate new groups for the immobilization of

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

• concentration (0.1 wt %), forming stable oil-in-water emulsions through interfacial adsorption by the CD nanogels. Conclusion: Soft CD nanogel particles adsorb at the oil–water interface with an effective coverage by forming a strong interconnected network and form a stable Pickering emulsion. The adsorption

• property of CD nanogels on the droplet surface has great potential to become new microcapsule building blocks with porous surfaces. These microcapsules may act as stimuli-responsive nanocarriers and nanocontainers. Keywords: crosslinked cyclodextrin polymer; interfacial adsorption; nanogel; Pickering

• emulsion; Introduction Pickering emulsions, which are emulsions stabilized by colloidal particles instead of conventional low-molecular-weight surfactants [1], are formed through the adsorption of colloidal particles at an oil–water interface to give stable emulsion droplets. Particle adsorption, which

Ru complexes of Hoveyda–Grubbs type immobilized on lamellar zeolites: activity in olefin metathesis reactions

• Hynek Balcar,
• Naděžda Žilková,
• Martin Kubů,
• Michal Mazur,
• Zdeněk Bastl and
• Jiří Čejka

Beilstein J. Org. Chem. 2015, 11, 2087–2096, doi:10.3762/bjoc.11.225

• organic ligands to induce adsorption or catalytic functionalities [29][30]. The detailed structures of zeolites MCM-22, MCM-36 and MCM-56 used as supports in this work are depicted in [31][32]. Results and Discussion Hybrid catalyst preparation and characterization Immobilization of HGIIN+X complexes

• decomposition of the PF6− anion and ligand exchange at the Ru atom most likely accompanied the immobilization. The XRD and nitrogen adsorption measurements confirmed that the layered structure of the supports was preserved in the prepared hybrid catalysts. The activity of hybrid catalysts was studied (i) in RCM

• passed through a column filled with activated alumina. Nitrogen adsorption/desorption isotherms were measured on a Micromeritics GEMINI II 2370 volumetric Surface Area Analyzer at liquid nitrogen temperature (−196 °C) to determine the surface area and pore volume. Prior to the sorption measurements, all

New palladium–oxazoline complexes: Synthesis and evaluation of the optical properties and the catalytic power during the oxidation of textile dyes

• Rym Hassani,
• Mahjoub Jabli,
• Yakdhane Kacem,
• Jérôme Marrot,
• Damien Prim and
• Béchir Ben Hassine

Beilstein J. Org. Chem. 2015, 11, 1175–1186, doi:10.3762/bjoc.11.132

• PdII ions, leading to the adsorption of dyes. Moreover, the decolorization of the solution by Pd and Pd complexes has also been applied [23]. In this paper, we report the synthesis and characterization of some new palladacycles. Optical properties were determined and the catalytic activity of these

Properties of PTFE tape as a semipermeable membrane in fluorous reactions

• Brendon A. Parsons,
• Olivia Lin Smith,
• Myeong Chae and
• Veljko Dragojlovic

Beilstein J. Org. Chem. 2015, 11, 980–993, doi:10.3762/bjoc.11.110

• to some compounds, such as dimethyl phthalate, solvent adsorption to the tape altered its permeability and allowed diffusion through channels of solvent within the PTFE tape. In this case, the solvent-filled pores of the PTFE tape are chemically more akin to the adsorbed solvent rather than to the

• through PTFE tape, even if though they do not wet the tape by adsorption [32]. Finally, when peroxide in tert-butanol/water (2:1) was the oxidant and 9,10-bis(phenylethynyl)anthracene the acceptor, solvent-assisted diffusion of dimethyl phthalate was visualized (Figure 14). One can observe bright green

• solid. As mentioned earlier, the pores are estimated from scanning electron micrographs to be about 0.5 μm in size and they may change in size and number if the tape is stretched [29][31]. The non-porous nature of bulk PTFE precludes the adsorption of other materials. This may be the reason why solvents

Carboxylated dithiafulvenes and tetrathiafulvalene vinylogues: synthesis, electronic properties, and complexation with zinc ions

• Yunfei Wang and
• Yuming Zhao

Beilstein J. Org. Chem. 2015, 11, 957–965, doi:10.3762/bjoc.11.107

• properties of the coordination polymer were investigated by infrared spectroscopy, cyclic voltammetry, powder X-ray diffraction, and differential scanning calorimetric analyses. Furthermore, the microscopic porosity and surface area of the Zn-TTFV coordination polymer were measured by nitrogen gas adsorption

• structures in the solid state with certain microscopic porosity. To assess the porous properties of Zn-TTFV 8, nitrogen gas adsorption analysis was conducted at 77 K. The adsorption isotherm shown in Figure 5A indicates a Type-II adsorption behaviour. Application of the Brunauer–Emmett–Teller (BET) model

• gave a BET surface area of 148.2 m2 g−1 and an adsorption average pore diameter of 10.2 nm. The pore size distribution analysis data revealed that Zn-TTFV coordination polymer 8 carried microporosity primarily in the range of tens of nanometers. Scanning electron microscopic (SEM) imaging was performed

Terminal lipophilization of a unique DNA dodecamer by various nucleolipid headgroups: Their incorporation into artificial lipid bilayers and hydrodynamic properties

• Emma Werz and
• Helmut Rosemeyer

Beilstein J. Org. Chem. 2015, 11, 913–929, doi:10.3762/bjoc.11.103

• aforementioned experiment, the oligomer 12 is highly resistant against perfusions. After 3 perfusions, interrupted by incubation periods of 10 min each, a constant normalized bilayer brightness of about 60–65% is reached, which stays constant for more than 1 h and 6 perfusions. Figure 8 displays the adsorption

• decreasing mobility of the oligomer from position 1 < position 2 < position 3 clearly indicates a loose adsorption at the bilayer (position 2) followed by incorporation within the bilayer (position 3). Obviously, at position 2 (which is only ≈5–10 µm away from the bilayer), an attractive interaction exists

Adsorption mechanism and valency of catechol-functionalized hyperbranched polyglycerols

• Stefanie Krysiak,
• Qiang Wei,
• Klaus Rischka,
• Andreas Hartwig,
• Rainer Haag and
• Thorsten Hugel

Beilstein J. Org. Chem. 2015, 11, 828–836, doi:10.3762/bjoc.11.92

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

• µM, unbound peptide could not be detected anymore whereas single and unbound nanoparticles are observed (Figure 7c). The obtained assemblies show a highly ordered adsorption of nanoparticles on the surface of the fiber in a three dimensional manner, which was supported by stereo Cryo TEM

Highly selective generation of vanillin by anodic degradation of lignin: a combined approach of electrochemistry and product isolation by adsorption

• Dominik Schmitt,
• Carolin Regenbrecht,
• Marius Hartmer,
• Florian Stecker and
• Siegfried R. Waldvogel

Beilstein J. Org. Chem. 2015, 11, 473–480, doi:10.3762/bjoc.11.53

• lignin research. So far most of the developed methods fail in technical application since no viable concept for work-up is included. This work represents a combined approach of electrochemical conversion of Kraft lignin and product recovery by adsorption on a strongly basic anion exchange resin

• acidification and precipitation of remaining lignin. The latter represents a significant advantage compared with conventional work-up protocols of lignin solutions. Keywords: adsorption; electrochemistry; lignin; nickel; renewable resources; Introduction The biopolymer lignin is one of the most abundant and

• phenolate stronger, ionic interactions usually dominate at basic pH [39]. But even under acidic conditions strong interactions between the polymer backbone and the adsorptive phase remain [40]. For this reason several commercially available resins were tested concerning their adsorption and desorption

IR and electrochemical synthesis and characterization of thin films of PEDOT grown on platinum single crystal electrodes in [EMMIM]Tf₂N ionic liquid

• Andrea P. Sandoval,
• Marco F. Suárez-Herrera and
• Juan M. Feliu

Beilstein J. Org. Chem. 2015, 11, 348–357, doi:10.3762/bjoc.11.40

• adsorption at the surface in which this vibrational mode is active. These features could mean that the consumption of anions (from the IL to inside the polymer) is directly related to the generation of positive charge, which occurs in two regions that correlate well with the peaks A1/C1 and A2/C2 observed in

Formulation development, stability and anticancer efficacy of core-shell cyclodextrin nanocapsules for oral chemotherapy with camptothecin

• Hale Ünal,
• Naile Öztürk and
• Erem Bilensoy

Beilstein J. Org. Chem. 2015, 11, 204–212, doi:10.3762/bjoc.11.22

• based on its amino groups. Coating with CS resulted in an increment in particle size due to the adsorption of CS molecules on the nanocapsule surface [34]. This coating is believed to be of importance due to the penetration enhancing properties of chitosan through the intestinal mucosa by opening of