Hyper-reticulated calixarene polymers: a new example of entirely synthetic nanosponge materials

• Alberto Spinella,
• Marco Russo,
• Antonella Di Vincenzo,
• Delia Chillura Martino and
• Paolo Lo Meo

Beilstein J. Org. Chem. 2018, 14, 1498–1507, doi:10.3762/bjoc.14.127

• [21][22][23][24][25][26][27]. The properties of CyNSs, in terms of physical and mechanical features, porosity, thermal stability and adsorption or release abilities, may be modulated up to a certain extent by a sensible choice of the linker unit, depending on its length and possible functionalization

• . For instance, increased porosity of the CyNS obtained has been recently claimed by the use of a rigid terephthalonitrile unit as the linker [13]. On the other hand, it has been recently shown that polyamine linkers give rise to pH-sensitive materials with tunable adsorption abilities [12]. In order to

• synthetic NS, and testing the supramolecular binging abilities of a material exclusively constituted by calixarene units. For these purposes, in the present work we describe the synthesis, the characterization and a preliminary study on the adsorption abilities of a set of new calixarene nanosponges (CaNSs

Spectroelectrochemical studies on the effect of cations in the alkaline glycerol oxidation reaction over carbon nanotube-supported Pd nanoparticles

• Dennis Hiltrop,
• Steffen Cychy,
• Karina Elumeeva,
• Wolfgang Schuhmann and
• Martin Muhler

Beilstein J. Org. Chem. 2018, 14, 1428–1435, doi:10.3762/bjoc.14.120

• like Cs+. A high surface coverage with such clusters was assumed to inhibit the adsorption and movement of reactants on the electrode surface accounting for the activity trends Li+ < Na+ < K+ < Cs+ in the investigated reactions [24]. This study gave rise to further investigations on the impact of ions

• on electrochemical reactions. Studies of the cation effect on Au electrodes are scarce [25][26], as the majority of reports employ Pt electrodes. In acidic medium the influence of Cs+ and Na+ on the specific adsorption of OH, O and H on polycrystalline Pt was investigated [27] as well as the cation

• of solvated Na+ clusters on the Pd NPs is supposed to be higher than for the corresponding K+ clusters and thus should hinder the adsorption/oxidation of glycerol leading to lower currents also for Pd/NCNT [24]. It has to be pointed out that a non-linearity of this cation effect has already been

A three-armed cryptand with triazine and pyridine units: synthesis, structure and complexation with polycyclic aromatic compounds

• Claudia Lar,
• Adrian Woiczechowski-Pop,
• Attila Bende,
• Ioana Georgeta Grosu,
• Natalia Miklášová,
• Elena Bogdan,
• Niculina Daniela Hădade,
• Anamaria Terec and
• Ion Grosu

Beilstein J. Org. Chem. 2018, 14, 1370–1377, doi:10.3762/bjoc.14.115

• 1 towards aromatic guests (anthracene, pyrene) in solution was observed and the formation of a cryptand–pyrene complex was revealed by cyclic voltammetry only after the adsorption of the cryptand on a graphite surface (electrode). In a more recent paper [33], authors who reobtained our cryptand 1

An alternative to hydrogenation processes. Electrocatalytic hydrogenation of benzophenone

• Cristina Mozo Mulero,
• Alfonso Sáez,
• Jesús Iniesta and
• Vicente Montiel

Beilstein J. Org. Chem. 2018, 14, 537–546, doi:10.3762/bjoc.14.40

• MHads (defining “M” as a metal adsorption site and Hads as atomic adsorbed hydrogen), (ii) adsorption of the organic molecule on a support site (two distinct adsorption sites are considered) and, (iii) electrocatalytic hydrogenation of the organic molecule through the adsorbed atomic hydrogen. It is

• important to note that, formation of “active hydrogen” is the main step in this process and hydrogen-active powder electrocatalysts such as Pd/C, Pt/C or Raney-nickel have been demonstrated as the optimal choice [16][17]. Moreover, the organic molecule adsorption rate must be faster than that one associated

• regard, after formation of PdHad, the recombination rate of this “atomic active hydrogen” into diatomic hydrogen gas should be slower than the adsorption rate of the organic compound over the cathode in order to prompt electrocatalytic hydrogenation; consequently, a low current density should favour the

Fluorogenic PNA probes

• Tirayut Vilaivan

Beilstein J. Org. Chem. 2018, 14, 253–281, doi:10.3762/bjoc.14.17

• ), HIV and HVB (hepatitis B virus surface antigen) in a single tube was demonstrated [141]. Addition of a very low concentration of bovine serum albumin (BSA, 0.01%) was shown to enhance the performance of the PNA–GO-based DNA sensing platform by reducing the non-specific adsorption of PNA–DNA duplexes

Exploring mechanochemistry to turn organic bio-relevant molecules into metal-organic frameworks: a short review

• Vânia André,
• Sílvia Quaresma,
• João Luís Ferreira da Silva and
• M. Teresa Duarte

Beilstein J. Org. Chem. 2017, 13, 2416–2427, doi:10.3762/bjoc.13.239

• MOFs, especially on BioMOFs. MOFs are among the most exciting structures and their range of applications is rather vast, including, but is not limited to ion exchange, adsorption and gas storage [56][57][58][59][60][61], separation processes [62], catalysis [63][64], polymerization reactions [65][66

• without solvent. This procedure delivered HKUST-1 with some improved properties, including higher microporosity and surface area, when compared to those made in solution and by other techniques [131]. The presence of unsaturated open metal sites turns this compound into a potential adsorption/desorption

Novel approach to hydroxy-group-containing porous organic polymers from bisphenol A

• Tao Wang,
• Yan-Chao Zhao,
• Li-Min Zhang,
• Yi Cui,
• Chang-Shan Zhang and
• Bao-Hang Han

Beilstein J. Org. Chem. 2017, 13, 2131–2137, doi:10.3762/bjoc.13.211

• 273 K and 1.0 bar. Meanwhile, the hydrogen and methane capacities are also investigated. Considering the gas adsorption properties, PPOPs may be a promising candidate for gas storage and separation materials. Results and Discussion Three multi-formyl compounds, i.e., two dialdehydes M1 and M2 [22] and

• , indicating the degradation of BPA catalyzed by TSA at high temperature [29][30]. Nitrogen sorption measurements were employed to evaluate the porosity of the obtained polymers. The nitrogen adsorption–desorption isotherms of PPOP-1–PPOP-3 are similar to each other (Figure 3a). All of the isotherms show a

• lowest BET surface area and total pore volume and micropore volume, which may arise from the fact that interactions between the accessible surface area, micropore volume, and pore topology contribute predominantly to methane storage capacity in porous material [33][34]. The carbon dioxide adsorption

New bio-nanocomposites based on iron oxides and polysaccharides applied to oxidation and alkylation reactions

• Daily Rodríguez-Padrón,
• Alina M. Balu,
• Antonio A. Romero and
• Rafael Luque

Beilstein J. Org. Chem. 2017, 13, 1982–1993, doi:10.3762/bjoc.13.194

• nanocomposites with diverse applications in catalysis, sensing, drug delivery and adsorption [25][26][27][28]. In addition, mechanochemical protocols have also been employed to functionalize the surfaces of magnetic nanoparticles (MNPs) with monosaccharides [29] and to obtain bio-nanocomposites based on proteins

• other two catalysts, a particular macroporosity was found at p/p0 > 0.98 (isotherms of type III), which are clearly dissimilar to those of conventionally ordered mesoporous materials [53] having a sharp increase in p/p0 from 0.85 to 0.90 (see Supporting Information File 1, Figure S5 for all adsorption

• detector. For the deconvolution of the obtained curves, the XPS software CASA was used. N2 physisorption The Brunauer–Emmett–Teller (BET) surface area and pore volume measurements were obtained from N2 adsorption–desorption isotherms at liquid nitrogen temperature (77 K) in a Micromeritics ASAP 2000

Ni nanoparticles on RGO as reusable heterogeneous catalyst: effect of Ni particle size and intermediate composite structures in C–S cross-coupling reaction

• Debasish Sengupta,
• Koushik Bhowmik,
• Goutam De and
• Basudeb Basu

Beilstein J. Org. Chem. 2017, 13, 1796–1806, doi:10.3762/bjoc.13.174

• composite, the electron-rich RGO surface helps in stabilizing the Ni in its zero-valent state. The high surface area and planar structure of RGO prevent the Ni NPs (to an optimum loading of Ni) from agglomeration and provide enough adsorption sites to the reacting molecules. In this work graphene oxide (GO

A recursive microfluidic platform to explore the emergence of chemical evolution

• David Doran,
• Marc Rodriguez-Garcia,
• Rebecca Turk-MacLeod,
• Geoffrey J. T. Cooper and
• Leroy Cronin

Beilstein J. Org. Chem. 2017, 13, 1702–1709, doi:10.3762/bjoc.13.164

• length scale to biological cells. Soft interface interactions at liquid–liquid boundaries in microdroplets can also have a catalytic effect via the adsorption of otherwise unstable molecules [16], similar to catalysis reported at liquid–mineral interfaces [17]. Microfluidic platform for artificial

Mechanochemical synthesis of graphene oxide-supported transition metal catalysts for the oxidation of isoeugenol to vanillin

• Ana Franco,
• Sudipta De,
• Alina M. Balu,
• Araceli Garcia and
• Rafael Luque

Beilstein J. Org. Chem. 2017, 13, 1439–1445, doi:10.3762/bjoc.13.141

• were characterized by using several techniques including BET, SEM, TEM, XRD, and IR spectroscopy. N2 adsorption/desorption isotherms of the reduced graphene sample (Figure 1a) can be classified as type IV corresponding to the mesoporous materials. The RGO sample showed a BET surface area of 103 m2 g−1

• diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM) and diffuse reflectance infrared Fourier transform spectroscopy (DRIFT). N2 adsorption measurements were performed at 77 K by using a Micromeritics ASAP 2000 volumetric adsorption analyzer. The samples were degassed

Synthesis of oligonucleotides on a soluble support

• Harri Lönnberg

Beilstein J. Org. Chem. 2017, 13, 1368–1387, doi:10.3762/bjoc.13.134

• . With 15–21-mer oligomers, some support-bound material, however, remained in solution and was recovered by adsorption to C18-coated silica gel. The cycle was completed by detritylation with DCA (3%) in DCM. Cleavage and deprotection was conventional: ammonolysis in aqueous EtOH, followed by desilylation

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

• design the mesopore volumes and their relatively narrow pore size distribution, the carbons are also interesting as model carbons for the investigation of different adsorption phenomena. Experimental Synthesis Citric acid monohydrate (CA, purity: 95.5%) and titanium isopropoxide (TIPP, purity: 97%) were

• achieved from (A) different amounts of ethylene glycol and (B) different syntheses. Volume histogram of the different samples calculated using a QSDFT-kernel for slit, cylindrical and spherical pores on the adsorption branch. Cyclic voltammograms performed with different scan rates in (A) 1 M TEA-BF4 (ACN

Biomimetic molecular design tools that learn, evolve, and adapt

• David A Winkler

Beilstein J. Org. Chem. 2017, 13, 1288–1302, doi:10.3762/bjoc.13.125

• include, phosphor brightness, drug binding efficacy, toxicity, catalytic efficiency, ability of the material to support the growth of cells, efficiency of gas adsorption, and many others. The relationship between the materials genome and the fitness can be presented as a surface, commonly called the

• calculations. However, these are intractable for libraries of millions of porous materials. Thornton et al. recently showed how a combined artificial intelligence-based modelling paradigm could be combined with evolutionary algorithms to discover materials with superior gas-adsorption properties in a more

Aqueous semisynthesis of C-glycoside glycamines from agarose

• Juliana C. Cunico Dallagnol,
• Alexandre Orsato,
• Diogo R. B. Ducatti,
• Miguel D. Noseda,
• Maria Eugênia R. Duarte and
• Alan G. Gonçalves

Beilstein J. Org. Chem. 2017, 13, 1222–1229, doi:10.3762/bjoc.13.121

• using ammonium carbonate (Table 1, entry 2) also ended up in a messy byproduct mixture and the poor isolated yield was also a consequence of the exhaustive chromatographic cleanup utilized. The most problematic issue was to avoid byproduct 6. Because of its similar adsorption characteristics to the

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

• the obtained polymers. The nitrogen adsorption–desorption isotherms (Figure 2a) of SugPOP-1–3 were measured at 77 K to explore the porosity of the obtained polymers. Both SugPOP-1 and SugPOP-3 show the combination of type I and IV sorption isotherms according to the IUPAC classification, whereas

• SugPOP-2 displays a type I sorption isotherm. A rapid uptake curve reflects the microporous monolayer adsorption tendency at low relative pressure (p/p0 < 0.10). As for SugPOP-1 and SugPOP-3, the significant hysteresis loops (0.50 < p/p0 < 1.00) are consistent with the mesoporous structure. The SSA value

• volume, and pore size, are calculated based on the corresponding isotherms and listed in Table 1. Such HCPs with a high SSA and micro/mesopore distribution inspired us to explore their gas uptake capacity. The CO2 adsorption isotherms of the three polymers at 1.0 bar and 273 K are shown in Figure S5

Automating multistep flow synthesis: approach and challenges in integrating chemistry, machines and logic

• Chinmay A. Shukla and
• Amol A. Kulkarni

Beilstein J. Org. Chem. 2017, 13, 960–987, doi:10.3762/bjoc.13.97

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