Selective formation of a zwitterion adduct and bicarbonate salt in the efficient CO₂ fixation by N-benzyl cyclic guanidine under dry and wet conditions

• Yoshiaki Yoshida,
• Naoto Aoyagi and
• Takeshi Endo

Beilstein J. Org. Chem. 2018, 14, 2204–2211, doi:10.3762/bjoc.14.194

• derivative and CO2 was isolated and characterized for the first time. Keywords: bicarbonate salt; carbon dioxide adsorption; cyclic guanidine; repeatable capture and release; zwitterion adduct; Introduction Recently, various reactions with CO2 as a cheap and green carbon reagent have been developed not

• structure of the guanidine moiety [39]. Furthermore, we also have demonstrated that the adsorption performance of CO2 was fairly different under dry and wet conditions [35]. Previously, Jessop et al. described that the bicarbonate salt of DBU and CO2 was obtained in the presence of water and never confirmed

Functionalization of graphene: does the organic chemistry matter?

• Artur Kasprzak,
• Agnieszka Zuchowska and
• Magdalena Poplawska

Beilstein J. Org. Chem. 2018, 14, 2018–2026, doi:10.3762/bjoc.14.177

• the epoxides of the graphene-family material. In a coupling with the inclusion of graphene-family material and amine hydrohalide some reactions or transformations may occur, but they are based on electrostatic adsorption or hydrogen bonding [23], rather than on covalent modification. If formation of

• vibrations) in the product’s IR spectrum. Therefore, it is not clear why a similar, prominent adsorption band corresponding to the amide moiety was not observed in the spectrum, and this issue was not discussed. It is noteworthy that both a lower intensity of the absorption band coming from the C=O of GO

• ], the approach to the synthesis of the material has not been given in some cases; in other words, the researchers have not always discussed whether the process is based on the non-covalent adsorption of the reactant or whether it follows the nucleophilic addition to GO’s epoxides. On the basis of the

Synthesis of new p-tert-butylcalix[4]arene-based polyammonium triazolyl amphiphiles and their binding with nucleoside phosphates

• Vladimir A. Burilov,
• Guzaliya A. Fatikhova,
• Mariya N. Dokuchaeva,
• Ramil I. Nugmanov,
• Diana A. Mironova,
• Pavel V. Dorovatovskii,
• Victor N. Khrustalev,
• Svetlana E. Solovieva and
• Igor S. Antipin

Beilstein J. Org. Chem. 2018, 14, 1980–1993, doi:10.3762/bjoc.14.173

• packaging density of aggregates and their general lipophilicity. To reveal this, absorbance spectra of the 10b–EY system in the presence of ADP and ATP were recorded (Figure 5a and b). The addition of small amounts of nucleotides leads to a bathochromic shift of the EY adsorption due to a deeper penetration

Assessing the possibilities of designing a unified multistep continuous flow synthesis platform

• Mrityunjay K. Sharma,
• Roopashri B. Acharya,
• Chinmay A. Shukla and
• Amol A. Kulkarni

Beilstein J. Org. Chem. 2018, 14, 1917–1936, doi:10.3762/bjoc.14.166

• continuous mode (CSTRs). Preheating and precooling are essential for getting reproducible and reliable experimental data. The third and final module includes separators viz. membrane separators/filters, scavengers or adsorption column (packed column), extractors/gravity separators, dryers, extruders, etc

• (reaction/drying/crystallization/adsorption/desorption), solubility data (extraction/crystallization), etc. This approach is useful for testing proof of the concept for a continuous process of various drugs which are in clinical trials. However, this approach may not be feasible for pilot or production

• cooled to 0 °C in the intermediate storage tank T5. The reaction mixture can pass through separator S1 (adsorption column) which is packed with MS 4 Å to remove the byproduct water. A solution of malonate and triethylamine in toluene are precooled to 0 °C in feed storage tanks and pumped to mixer M6

Graphitic carbon nitride prepared from urea as a photocatalyst for visible-light carbon dioxide reduction with the aid of a mononuclear ruthenium(II) complex

• Kazuhiko Maeda,
• Daehyeon An,
• Ryo Kuriki,
• Daling Lu and
• Osamu Ishitani

Beilstein J. Org. Chem. 2018, 14, 1806–1812, doi:10.3762/bjoc.14.153

• ]. Adsorption of RuP onto Ag/g-C3N4 was conducted by dispersing 40 mg of Ag/g-C3N4 in an acetonitrile (MeCN) solution (20 mL) of RuP. The suspension was stirred overnight at room temperature in the dark to allow for the adsorption/desorption equilibrium, followed by filtration and washing with acetonitrile. The

• filtrates were collected and concentrated to a volume of 30 mL. The amount of the ruthenium complex absorbed was calculated based on the UV–vis spectrum of the filtrate, using Equation 1: where Abefore and Aafter are the absorbance of the solution before and after the adsorption procedure, respectively, and

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