Particle size effect in the mechanically assisted synthesis of β-cyclodextrin mesitylene sulfonate

• Stéphane Menuel,
• Sébastien Saitzek,
• Eric Monflier and
• Frédéric Hapiot

Beilstein J. Org. Chem. 2020, 16, 2598–2606, doi:10.3762/bjoc.16.211

• the Brunauer–Emmett–Teller (BET) surface adsorption method. The obtained values were in good agreement with those obtained from the exploitation of the SEM images (Table 1). The specific surface area (SSA) of the β-CD samples ground over various periods of time was also extracted from the BET analysis

• the measurement of ca. 225 particles found in an arbitrarily chosen area of the images using the ImageJ software (version 1.4.3.67) [32]. After calibrating from the scale of the SEM images, the software provides the Feret diameter. BET (adsorption of N2) Dinitrogen sorption isotherms were collected at

• −196 °C using an adsorption analyzer Micromeritics Tristar II 3020. Prior to analysis, 80 mg samples were degassed at 100 °C overnight under vacuum. The specific area was computed using the Brunauer–Emmett–Teller (BET) equation over a range of relative pressure (P/P0) from 0.001 to 1, while the pore

Photosensitized direct C–H fluorination and trifluoromethylation in organic synthesis

• Shahboz Yakubov and
• Joshua P. Barham

Beilstein J. Org. Chem. 2020, 16, 2151–2192, doi:10.3762/bjoc.16.183

• , metabolic stability, adsorption and excretion properties of the compound [16][17]. For example, the pharmacokinetics of drugs are mostly regulated by the balance of the lipophilicity, hydrophilicity and ionization state. Since C–H/C–F substitution in a drug molecule enhances the lipophilicity [18], this has

Synergy between supported ionic liquid-like phases and immobilized palladium N-heterocyclic carbene–phosphine complexes for the Negishi reaction under flow conditions

• Edgar Peris,
• Raúl Porcar,
• María Macia,
• Jesús Alcázar,
• Eduardo García-Verdugo and
• Santiago V. Luis

Beilstein J. Org. Chem. 2020, 16, 1924–1935, doi:10.3762/bjoc.16.159

• fivefold larger fixed bed reactor (2.9 mL vs 0.5 mL) was used, leading to a larger residence time (29 min vs 2.5 min). An increase in the residence time may favor the re-adsorption of the active species into the support limiting, at some extent, the Pd leaching. The results obtained under these conditions

One-pot synthesis of isosorbide from cellulose or lignocellulosic biomass: a challenge?

• Isaline Bonnin,
• Raphaël Mereau,
• Thierry Tassaing and
• Karine De Oliveira Vigier

Beilstein J. Org. Chem. 2020, 16, 1713–1721, doi:10.3762/bjoc.16.143

• first run was observed. A sustainable method for the isosorbide production from cellulose is the use of a bifunctional catalyst (Scheme 7). A series of Ru catalysts on acid support were prepared by the adsorption of colloidal Ru nanoparticles on mesoporous and bulk niobium phosphate, mesoporous and bulk

Synthesis of new dihydroberberine and tetrahydroberberine analogues and evaluation of their antiproliferative activity on NCI-H1975 cells

• Giacomo Mari,
• Lucia De Crescentini,
• Serena Benedetti,
• Francesco Palma,
• Stefania Santeusanio and
• Fabio Mantellini

Beilstein J. Org. Chem. 2020, 16, 1606–1616, doi:10.3762/bjoc.16.133

• role of intermediates. However, pharmacokinetic studies have shown that, compared with BER [25], DHBER displayed improved adsorption and enhanced bioavailability, as also confirmed by several papers that describe how the gut microbiota converts BER derivatives into its absorbable form DHBER, which has

Mechanochemical green synthesis of hyper-crosslinked cyclodextrin polymers

• Alberto Rubin Pedrazzo,
• Fabrizio Caldera,
• Marco Zanetti,
• Silvia Lucia Appleton,
• Nilesh Kumar Dhakar and
• Francesco Trotta

Beilstein J. Org. Chem. 2020, 16, 1554–1563, doi:10.3762/bjoc.16.127

• ) synthesis. Conditions: nitrogen flow, ramp rate 10 °C/min, rt to 700 °C. Thermogravimetric analysis of α, β and γ-CD-based carbonate nanosponges, obtained through ball-mill synthesis. Conditions: nitrogen flow, ramp rate 10 °C/min. Adsorption of organic dyes by ball-mill synthesized β-CD-based carbonate

• nanosponges. Conditions: a small amount of NS (50 mg) was added to a clear solution containing the dye (10 mL). After the adsorption and the deposition of the NSs powder containing the organic dye, a clear solution was obtained. ζ-Potential of bm cyclodextrin nanosponges with relative STDev (mV). Hydrolysis

Heterogeneous photocatalysis in flow chemical reactors

• Christopher G. Thomson,
• Ai-Lan Lee and
• Filipe Vilela

Beilstein J. Org. Chem. 2020, 16, 1495–1549, doi:10.3762/bjoc.16.125

• . This energy is alleviated though surface relaxation, a process in which the surface changes its structure to reduce its energy, or by the adsorption of substrates to fill and stabilise vacancies. Water molecules adsorb to oxygen vacancies on the TiO2 surface and undergo a 2-electron reduction and

• recommend exploring the article for further details [95]. Molecules with functional groups such as carboxylic acid present complex surface topologies from bridging and bidentate binding modes [91]. Yoshida and co-workers studied the adsorption of benzene derivatives on TiO2 surfaces by solid-state NMR and

• photocatalytic degradation of basic organic dyes containing sulfonate groups, remazol black 5 (3, Figure 7) and procion red MX-5B (4, Figure 7), and showed a significant enhancement of 4 adsorption when the pH value was reduced to 3 (Figure 7) [98]. The authors stated that this reflected a higher positive charge

Activated carbon as catalyst support: precursors, preparation, modification and characterization

• Melanie Iwanow,
• Tobias Gärtner,
• Volker Sieber and
• Burkhard König

Beilstein J. Org. Chem. 2020, 16, 1188–1202, doi:10.3762/bjoc.16.104

• be produced by salt templating or ultrasonic spray pyrolysis as well as by microwave irradiation. The resulting activated carbon materials are characterized by a variety of techniques such as SEM, FTIR, nitrogen adsorption, Boehm titrations, adsorption of phenol, methylene blue and iodine, TPD, CHNS

• the surface of the treated carbons in form of carboxyl groups, ketones, ether groups and carboxyl-carbonate structures is higher using nitric acid compared to hydrogen peroxide [116]. Nitrogen adsorption–desorption isotherms: The surface area and pore size distribution of solid catalyst materials can

• be determined by gas adsorption–desorption measurements at 77 K. To obtain reproducible isotherms from the measurements, a controlled outgassing of the adsorbent with a defined temperature, change in pressure and residual pressure is necessary to remove all physisorbed species from the surface

The charge-assisted hydrogen-bonded organic framework (CAHOF) self-assembled from the conjugated acid of tetrakis(4-aminophenyl)methane and 2,6-naphthalenedisulfonate as a new class of recyclable Brønsted acid catalysts

• Svetlana A. Kuznetsova,
• Alexander S. Gak,
• Yulia V. Nelyubina,
• Vladimir A. Larionov,
• Han Li,
• Michael North,
• Vladimir P. Zhereb,
• Alexander F. Smol'yakov,
• Artem O. Dmitrienko,
• Michael G. Medvedev,
• Igor S. Gerasimov,
• Ashot S. Saghyan and
• Yuri N. Belokon

Beilstein J. Org. Chem. 2020, 16, 1124–1134, doi:10.3762/bjoc.16.99

• produced gases (Figures S11 and S12, Supporting Information File 1). The CAHOF F-1 was also analyzed by nitrogen porosimetry (see Supporting Information File 1). It was found to contain mesopores and macropores with an adsorption average pore width of 5.2 nm, a BET surface area of 2.606 m2⋅g−1, a mesopore

A systematic review on silica-, carbon-, and magnetic materials-supported copper species as efficient heterogeneous nanocatalysts in “click” reactions

• Pezhman Shiri and
• Jasem Aboonajmi

Beilstein J. Org. Chem. 2020, 16, 551–586, doi:10.3762/bjoc.16.52

• /mechanical stability, and good adsorption capacity. They also contain an ordered porous network that is appropriate for the free diffusion of reactants and reaction products [24]. In this regard, various functionalized SiO2 nanoparticles were employed in diverse organic reactions, including Suzuki–Miyaura

Carbazole-functionalized hyper-cross-linked polymers for CO₂ uptake based on Friedel–Crafts polymerization on 9-phenylcarbazole

• Dandan Fang,
• Xiaodong Li,
• Meishuai Zou,
• Xiaoyan Guo and
• Aijuan Zhang

Beilstein J. Org. Chem. 2019, 15, 2856–2863, doi:10.3762/bjoc.15.279

• a high surface area and a high total pore volume. The BET specific surface areas of P3 was up to 769 m2 g−1 with narrow pore size distribution and the CO2 adsorption capacity of P11 was up to 52.4 cm3 g−1 (273 K/1.00 bar). Keywords: 9-phenylcarbazole; CO2 uptake; Friedel–Crafts polymerization

• amorphous polymers [12] (Figure 5). Porous properties The permanent porous nature was subsequently studied by subjecting the polymers to nitrogen adsorption–desorption experiments at 77 K. The porosity data of P1–P11 are listed in Table 2. The main influence of the porous properties is the reaction degree

• , P2–P5 exhibited a rapid nitrogen adsorption ability at low pressures (P/P0 < 0.05, Figure 6a), which indicated that the micropores exist in the networks [35]. The sorption isotherm of P2–P4 exhibited a combination of type I and IV nitrogen sorption isotherms according to the IUPAC classification [36

A review of asymmetric synthetic organic electrochemistry and electrocatalysis: concepts, applications, recent developments and future directions

• Munmun Ghosh,
• Valmik S. Shinde and
• Magnus Rueping

Beilstein J. Org. Chem. 2019, 15, 2710–2746, doi:10.3762/bjoc.15.264

• electrodes Electrodes with chiral surfaces have long been prepared through the adsorption of chiral active auxiliaries onto the surface of the metallic electrode. In such cases, the chiral electrode becomes an inherent part of the electrochemical cell and serves as a heterogeneous catalyst. A recent article

Nanopatterns of arylene–alkynylene squares on graphite: self-sorting and intercalation

• Tristan J. Keller,
• Joshua Bahr,
• Kristin Gratzfeld,
• Nina Schönfelder,
• Marcin A. Majewski,
• Marcin Stępień,
• Sigurd Höger and
• Stefan-S. Jester

Beilstein J. Org. Chem. 2019, 15, 1848–1855, doi:10.3762/bjoc.15.180

• with different numbers of sides [18], that are scalable to some extent [19]. The long alkoxy side chains mediate sufficient compound solubility and compound adsorption on highly oriented pyrolytic graphite (HOPG) that acts as a template [20][21], and determine the intermolecular interaction [22][23][24

• , some rows of more densely packed molecules (polymorph B) are observed, where two (arrow 1 in Figure 3a) or all four (arrow 2 in Figure 3a) decyloxy side chains are oriented towards the intraannular region. This is consistent with the spatial requirements of 2, which compete with the adsorption of 1a

•  1). Conclusion Arylene–alkynylenes that carry alkoxy side chains form, after adsorption to graphite, a nanopattern with intra- and intermolecular nanopores. Clusters of otherwise unhinderedly mobile 1,2,4-trichlorobenzene solvent molecules are found in these nanopores. Subtle changes of the pore

Norbornadiene-functionalized triazatriangulenium and trioxatriangulenium platforms

• Roland Löw,
• Talina Rusch,
• Tobias Moje,
• Fynn Röhricht,
• Olaf M. Magnussen and
• Rainer Herges

Beilstein J. Org. Chem. 2019, 15, 1815–1821, doi:10.3762/bjoc.15.175

• ]. Three molecular units are combined in a modular way to achieve a controlled adsorption on the surface: the platform, a spacer and the functional molecule. Triazatriangulenium (TATA) and trioxatriangulenium (TOTA) units are used as molecular platforms. They adsorb on the surface and form ordered

• as realized in compound 1. Consequently, future surface chemistry investigations will be performed with compound 1 including the TATA platform and an ethynyl spacer. STM Measurements The adsorption behaviour of the NBD 1a on Au(111) surfaces was studied by scanning tunnelling microscopy (STM) at room

Functional panchromatic BODIPY dyes with near-infrared absorption: design, synthesis, characterization and use in dye-sensitized solar cells

• Quentin Huaulmé,
• Cyril Aumaitre,
• Outi Vilhelmiina Kontkanen,
• David Beljonne,
• Alexandra Sutter,
• Gilles Ulrich,
• Renaud Demadrille and
• Nicolas Leclerc

Beilstein J. Org. Chem. 2019, 15, 1758–1768, doi:10.3762/bjoc.15.169

• electrolyte one can tune the electronic properties, i.e., the CB energy level position of TiO2 [31][37][38][39]. The effect is well-known, a negative dipole-related shift of the TiO2 Fermi level occurs by tBP adsorption on the surface. As the LUMO levels of the dyes are estimated close to the CB Fermi level

Synthesis and conformational preferences of short analogues of antifreeze glycopeptides (AFGP)

• Małgorzata Urbańczyk,
• Michał Jewgiński,
• Joanna Krzciuk-Gula,
• Jerzy Góra,
• Rafał Latajka and
• Norbert Sewald

Beilstein J. Org. Chem. 2019, 15, 1581–1591, doi:10.3762/bjoc.15.162

• microscopic mechanism of ice–glycoprotein interaction is still unknown. Therefore, it is an interesting area for further research [3][10][11]. Some studies have highlighted the role of irreversible adsorption of AFGPs onto growing ice surface and incorporation of hydroxy groups of the disaccharide subunit

• into the ice lattice [12], others investigated the adsorption process on different surfaces via atomic force microscopy [10][13][14]. The antifreeze activity has been correlated with long-range perturbation of hydration dynamics [15]. Latest molecular dynamics simulations suggest that AFGP reversibly

Diazocine-functionalized TATA platforms

• Roland Löw,
• Talina Rusch,
• Fynn Röhricht,
• Olaf Magnussen and
• Rainer Herges

Beilstein J. Org. Chem. 2019, 15, 1485–1490, doi:10.3762/bjoc.15.150

• . The half-lives (298 K) are similar for both systems (2.12 h for 1 and 2.32 h for 2). The lack of conjugation between the azo function and the ethynyl spacer of 2 yields in a slightly higher half-life, which is in agreement with earlier results [11]. STM Measurements The adsorption behavior of the

Reaction of oxiranes with cyclodextrins under high-energy ball-milling conditions

• László Jicsinszky,
• Federica Calsolaro,
• Katia Martina,
• Fabio Bucciol,
• Maela Manzoli and
• Giancarlo Cravotto

Beilstein J. Org. Chem. 2019, 15, 1448–1459, doi:10.3762/bjoc.15.145

• seen in Figure 2 and Figure 3. Although scaled-up β-CDP has somehow larger particles, complexation studies with methyl orange (MO) only showed small differences. Although complex formation with MO showed similar behaviour to previous reports [13], adsorption capacity seems to be considerably lower than

• that of bead polymers in all cases. The adsorption of MO shows apparent first order kinetics, and the largest adsorption rates were accordingly found at the beginning of adsorption. The adsorption isotherm of insoluble β-CDP was recorded after 1 day and 2 weeks of equilibration. The adsorption isotherm

• GPTS-γ-CD. The adsorption isotherm can also be divided in two parts; the simple adsorptive removal of MO can be seen at the beginning, while the MO peak showed a noticeable blue-shift as the amount of solubilised/dissolved γ-CD-derivative increased. Conclusion The use of the HEBM method to force the

Mechanochemical amorphization of chitin: impact of apparatus material on performance and contamination

• Thomas Di Nardo and
• Audrey Moores

Beilstein J. Org. Chem. 2019, 15, 1217–1225, doi:10.3762/bjoc.15.119

• amounts of material from the jars and balls in the reagents and products as a contamination. Milling media can have a catalytic effect due to leaching or surface adsorption [7][35][36][37]. Contamination has been noted in alloying [26][38] as well as amorphization of hard materials [39], and could cause

Mechanochemical synthesis of hyper-crosslinked polymers: influences on their pore structure and adsorption behaviour for organic vapors

• Sven Grätz,
• Sebastian Zink,
• Hanna Kraffczyk,
• Marcus Rose and
• Lars Borchardt

Beilstein J. Org. Chem. 2019, 15, 1154–1161, doi:10.3762/bjoc.15.112

• intrinsic property. Thus, the pore volume and specific surface area that is permanently accessible can be increased by a severe swelling behaviour especially during the adsorption and combined with absorption of organic vapors or liquids. The swelling is fully reversible, thus, rendering these materials

• interesting adsorbents with a dynamic adsorption behaviour. However, the low solubility of POPs is a main challenge in their synthesis protocols. Solution-based procedures, for example, suffer from almost instant precipitation and thus only produce materials with a low degree of polymerization [10]. In the

• obtained for diethyl ether (Table 1, entry 7) this sample has been denoted LAG-HCP and was investigated further. Vapor physisorption Since HCP is highly hydrophobic (proven before by water vapor physisorption [11]), the adsorption of non-polar adsorptives in the gas and liquid phase is strongly favored

Fabrication, characterization and adsorption properties of cucurbit[7]uril-functionalized polycaprolactone electrospun nanofibrous membranes

• Changzhong Chen,
• Fengbo Liu,
• Xiongzhi Zhang,
• Zhiyong Zhao and
• Simin Liu

Beilstein J. Org. Chem. 2019, 15, 992–999, doi:10.3762/bjoc.15.97

• present in the PCL fiber matrix in an uncomplexed state. The static adsorption behavior of the PCL/CB[7] nanofibers towards methylene blue (MB) was also preliminary investigated. The results indicate that the adsorption of MB onto the nanofibrous membranes fits the second-order kinetic model and Langmuir

• isotherm model. Keywords: adsorption; cucurbit[7]uril; electrospinning; macrocycles; methylene blue; nanofiber; Introduction Electrospinning is recognized as the most simple and versatile method to fabricate multifunctional nanofibers from the solution or melt of polymers, polymer/nanoparticle mixtures

• ]-containing functional materials, the feasibility of CB[7] (the chemical structure is shown in Supporting Information File 1, Figure S1)-based nanofibers through electrospinning was studied for the first time. In addition, the adsorption properties of the fabricated nanofibers were also preliminarily

Synthesis of polydicyclopentadiene using the Cp₂TiCl₂/Et₂AlCl catalytic system and thin-layer oxidation of the polymer in air

• Zhargolma B. Bazarova,
• Ludmila S. Soroka,
• Alex A. Lyapkov,
• Мekhman S. Yusubov and
• Francis Verpoort

Beilstein J. Org. Chem. 2019, 15, 733–745, doi:10.3762/bjoc.15.69

• and can be determined by the increase of carbonyl and hydroxyl adsorption bands in infrared spectra. Along with oxidation, cross-linking processes occur in polymers, which lead to a change in physical parameters of the layers, and more precisely to a decrease in the permeability of atmospheric oxygen

• adsorption of oxygen and its transport through the polymer layer becomes the slowest process, which leads to a change in shape of the kinetic curve of the accumulation of peroxide radicals (Figure 13). The curve in Figure 13 averages the experimental points of the oxidation process and is a result of two

• to air oxidation for 700 hours. DSC exotherm for PDCPD subjected to unexposed film: 1) in air atmosphere; 2) in argon. Dependence of intensities of adsorption bands at 1410 and 700 cm−1 and dwell time of the layer in air at ambient temperature. Semi-logarithmic kinetic curve of PDCPD oxidation in air

Adhesion, forces and the stability of interfaces

• Robin Guttmann,
• Johannes Hoja,
• Christoph Lechner,
• Reinhard J. Maurer and
• Alexander F. Sax

Beilstein J. Org. Chem. 2019, 15, 106–129, doi:10.3762/bjoc.15.12

MoO₃ on zeolites MCM-22, MCM-56 and 2D-MFI as catalysts for 1-octene metathesis

• Hynek Balcar,
• Martin Kubů,
• Naděžda Žilková and
• Mariya Shamzhy

Beilstein J. Org. Chem. 2018, 14, 2931–2939, doi:10.3762/bjoc.14.272

• . Moreover, for related system based on tungsten oxide in zeolite, it was suggested using high resolution STEM that Brønsted acid sites in proximity to metathesis active sites facilitate olefin adsorption and metallocycle formation [29]. Such mechanism may be effective also for Mo catalysts. The decrease in

• temperature for 3 h. The supports were characterized by XRD (Bruker AXS D8 Advance diffractometer with a graphite monochromator and a Vantec-1 position sensitive detector using Cu Kα radiation in Bragg−Brentano geometry) and by N2 adsorption (77 K, Micromeritics GEMINI II 2370 volumetric Surface Area Analyzer

• adsorption was carried out at 150 °C and a partial pressure of 3.5 torr for 20 min followed by desorption for 20 min at 150, 250, 350 or 450 °C. Before adsorption, pyridine was degassed by freeze–pump–thaw cycles. All spectra were recorded with a resolution of 4 cm–1 by collecting 128 scans for a single

Synthesis of unnatural α-amino esters using ethyl nitroacetate and condensation or cycloaddition reactions

• Glwadys Gagnot,
• Vincent Hervin,
• Eloi P. Coutant,
• Sarah Desmons,
• Racha Baatallah,
• Victor Monnot and
• Yves L. Janin

Beilstein J. Org. Chem. 2018, 14, 2846–2852, doi:10.3762/bjoc.14.263

• heat, adsorption over silica, acids (BF3·OEt2, AcOH) or bases (NEt3, LDA, EtONa) all failed to change the ratio of compounds 28 and 29, which were isolated in 5 and 28% yield, respectively. Despite the potential synthetic interest [29][30] of isoxazole 28, we did not pursue this further, but focused on