Factors influencing the performance of organocatalysts immobilised on solid supports: A review

• Zsuzsanna Fehér,
• Dóra Richter,
• Gyula Dargó and
• József Kupai

Beilstein J. Org. Chem. 2024, 20, 2129–2142, doi:10.3762/bjoc.20.183

• support can lead to lower stereoselectivity, as previously shown in Scheme 4. Solutions for limitations of solid-supported organocatalysts The properties and applicability of an immobilised catalyst depend not only on the immobilisation method and the physicochemical characteristics, porosity, and

Preparing a liquid crystalline dispersion of carbon nanotubes with high aspect ratio

• Keiko Kojima,
• Nodoka Kosugi,
• Hirokuni Jintoku,
• Kazufumi Kobashi and
• Toshiya Okazaki

Beilstein J. Org. Chem. 2024, 20, 52–58, doi:10.3762/bjoc.20.7

• buoyancy resulting from particle porosity [22][23][27][28]. Indeed, the DWCNT agglomerates having corresponding size can be seen in the optical microscope image of the dispersion (Figure 1b). The shapes of DWCNTs in the dispersion were examined by scanning electron microscopy (SEM) and atomic force

Light-responsive rotaxane-based materials: inducing motion in the solid state

• Adrian Saura-Sanmartin

Beilstein J. Org. Chem. 2023, 19, 873–880, doi:10.3762/bjoc.19.64

• maleamides (Z)-3 in the solid state (Figure 3a), leading to an enhancement in the porosity of the metal-organic crystalline material. Noteworthy, a MOF having (Z)-3 as the only ligand was also prepared, showing a faster rotational dynamics of the threads within the crystalline array compared to that of

• complete release of the cargo by the partial photoconversion of the fumaramide motifs that change porosity and hydrogen bonding interactions of the counterparts; and (iii) recovery of the starting material through a thermal treatment, allowing the reusability of the nanodispenser. The molecular cargo

Preparation of β-cyclodextrin/polysaccharide foams using saponin

• Max Petitjean and
• José Ramón Isasi

Beilstein J. Org. Chem. 2023, 19, 78–88, doi:10.3762/bjoc.19.7

• polysaccharides. Xanthan gum, locust bean gum or chitosan can be crosslinked using citric acid in the presence of β-cyclodextrin to produce insoluble matrices. In this work, polymeric foams based on those polysaccharides and saponin have been prepared using a green synthesis method to increase the porosity of the

• matrices. The saponin of soapbark (Quillaja saponaria) has been used to obtain foams using different procedures. The influence of the synthesis path on the porosity of the materials and their corresponding sorption capacities in the aqueous phase were evaluated. Keywords: chitosan; cyclodextrin polymers

• the presence of porosity and some chemical functions after pyrolysis. Chitosan–saponin–bentonite composite films can also be produced to absorb methyl orange and Cr(VI) [27]. Native [28] or derivatized [29] chitosans allow also a good sorption of Quillaja saponins useful to liberate them from wound

An alternative C–P cross-coupling route for the synthesis of novel V-shaped aryldiphosphonic acids

• Stephen J. I. Shearan,
• Enrico Andreoli and
• Marco Taddei

Beilstein J. Org. Chem. 2022, 18, 1518–1523, doi:10.3762/bjoc.18.160

• often either non-porous or have low porosity and have little to no long-range order. The idea here was that the V-shaped linkers, as well as different substituents attached to nitrogen, could potentially force a non-layered porous structure. Conventionally, the transition-metal-catalyzed C–P cross

Polymer and small molecule mechanochemistry: closer than ever

• José G. Hernández

Beilstein J. Org. Chem. 2022, 18, 1225–1235, doi:10.3762/bjoc.18.128

• for the fullerenes to pass through. However, the capsule 5 is sensitive to mechanochemical stress due to the porosity, conformational rigidity, and due to the presence of hydrazone and/or disulfide moieties that act as mechanophores. Therefore, during ball milling, 5 gets partially disintegrated at

Shift of the reaction equilibrium at high pressure in the continuous synthesis of neuraminic acid

• Jannis A. Reich,
• Miriam Aßmann,
• Kristin Hölting,
• Paul Bubenheim,
• Jürgen Kuballa and
• Andreas Liese

Beilstein J. Org. Chem. 2022, 18, 567–579, doi:10.3762/bjoc.18.59

• purposes, six different carriers were used to immobilize the epimerase and aldolase (Table 1). The carriers differ in their properties (size, hydrophobicity, binding type, and porosity). The quality of immobilization was evaluated in terms of enzyme loading, activity, and reusability in repetitive batch

• 2018a using the trapz function. The given values for τ do not account for the porosity of the packed bed. They are calculated via Equation 1 with V as the volume of the empty reactor and as the volumetric flow rate. Kinetics To investigate the influence of pressure on the selected reaction, a

Cryogels: recent applications in 3D-bioprinting, injectable cryogels, drug delivery, and wound healing

• Luke O. Jones,
• Leah Williams,
• Tasmin Boam,
• Martin Kalmet,
• Chidubem Oguike and
• Fiona L. Hatton

Beilstein J. Org. Chem. 2021, 17, 2553–2569, doi:10.3762/bjoc.17.171

• properties Cryogels are macroporous hydrogels with interconnected porosity, with high swelling capacities and large surface areas. Ultimately, many of the final cryogel properties are dependent on the choice of polymer/monomer composition used. However, other factors such as crosslinking, pore size, wall

• mechanical and thermal properties of the cryogel. Mechanical properties are mainly influenced by porosity and degree of crosslinking, while crosslinking also influences biocompatibility and degradability. In chemically crosslinked cryogels the mechanical properties can be influenced by the degree of

• [20]. This finding was further reiterated by Sen et al., who also explored heterogeneous pore size distribution for tissue engineering applications [21]. Cryostructuring, including directional freezing of cryogels, has been used to achieve varying degrees of porosity and aligned porosity or anisotropy

Constrained thermoresponsive polymers – new insights into fundamentals and applications

• Patricia Flemming,
• Alexander S. Münch,
• Andreas Fery and
• Petra Uhlmann

Beilstein J. Org. Chem. 2021, 17, 2123–2163, doi:10.3762/bjoc.17.138

Photoinduced post-modification of graphitic carbon nitride-embedded hydrogels: synthesis of 'hydrophobic hydrogels' and pore substructuring

• Cansu Esen and
• Baris Kumru

Beilstein J. Org. Chem. 2021, 17, 1323–1334, doi:10.3762/bjoc.17.92

• represents a family of materials where variety of synthetic routes can be applied to form photoactive matter with altered properties, i.e., monomer supramolecular assembly to attain a monomer complex prior to carbonization results in enhanced porosity and photoactivity since ordered structures are formed

• buried in the hydrogel to perform a photoinduced modification. It must be mentioned that the light transmission is limited since the hydrogel substrate is not fully transparent, and this envisions the importance of porosity as a key factor to diffuse and reflect the incoming light that can reach embedded

A comprehensive review of flow chemistry techniques tailored to the flavours and fragrances industries

• Guido Gambacorta,
• James S. Sharley and
• Ian R. Baxendale

Beilstein J. Org. Chem. 2021, 17, 1181–1312, doi:10.3762/bjoc.17.90

Valorisation of plastic waste via metal-catalysed depolymerisation

• Francesca Liguori,
• Carmen Moreno-Marrodán and
• Pierluigi Barbaro

Beilstein J. Org. Chem. 2021, 17, 589–621, doi:10.3762/bjoc.17.53

• °C provided a hydrocarbon oil in 92% yield, 71.4% of which were attributable to styrene monomer [156]. A decrease of 56 kJ mol−1 for the activation energy of PS depolymerisation was calculated in the presence of the catalysts. More recently, high-porosity montmorillonite (Mt) was used to prepare Mg

Dawn of a new era in industrial photochemistry: the scale-up of micro- and mesostructured photoreactors

• Emine Kayahan,
• Mathias Jacobs,
• Leen Braeken,
• Leen C.J. Thomassen,
• Simon Kuhn,
• Tom van Gerven and
• M. Enis Leblebici

Beilstein J. Org. Chem. 2020, 16, 2484–2504, doi:10.3762/bjoc.16.202

• calculation of the internal mass and light transfer limitations. The catalyst thickness should be adjusted so that all of the catalyst is utilized. The optimum catalyst thickness would depend on the interplay of many parameters, such as the porosity of the catalyst and the support, the flow rate of the

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

• wheat straw pulp led to 63% of isosorbide, corresponding to a productivity of 40 g·L−1·h−1 with 72% of purity. This high yield can be ascribed to several parameters such as small particle diameter, large surface area/porosity and lower crystallinity. For the particle size, cellulose fiber diameters are

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

• area and porosity, and (v) a strong affinity for the association of reactants to the surface and rapid dissociation of photochemical products. A few of these strategies are represented in Figure 12 and discussed in more detail within this section. Specific examples and applications are also given later

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

• compositions [2]. In general, activated carbon is an amorphous carbon modification with a high surface area and a well-developed porosity, which can be produced from a variety of carbon sources [3]. The preparation of activated carbons is already broadly covered in the literature. Therefore, we limit our brief

• investigated the influence of the different physical activation gases on the development of porosity from olive stone-based chars. They concluded that activation with steam results in activated carbon materials with lower micropore volumes and wider pore size distributions (higher amounts of meso- and

• advantages of the chemical activation are lower temperatures for pyrolysis, the formation of very high surface areas and it is possible to control the development of microporosity, e.g., a narrow pore size distibution can be obtained [8][15]. Various parameters influence the formation of porosity during the

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

• Dandan Fang Xiaodong Li Meishuai Zou Xiaoyan Guo Aijuan Zhang School of Materials Science & Engineering, Beijing Institute of Technology, Beijing 100081, China 10.3762/bjoc.15.279 Abstract To systematically explore the effects of the synthesis conditions on the porosity of hyper-cross-linked

• structure of the obtained polymers. The TG analysis of the HCPs showed good thermal stability. More importantly, a comparative study on the porosity revealed that: the molar ratio of cross-linker to monomer was the main influence factor of the BET specific surface area. Increasing the reaction temperature

• outstanding porous properties. Studies of the effects on porosity of HCPs are significant, but almost all investigations focused on the role of monomer length and geometry on the porosity [6][19][20][21][22][23][24][25][26][27][28][29][30][31][32]. Researchers have synthesized a series of carbazole-based

Ugi reaction-derived prolyl peptide catalysts grafted on the renewable polymer polyfurfuryl alcohol for applications in heterogeneous enamine catalysis

• Alexander F. de la Torre,
• Gabriel S. Scatena,
• Oscar Valdés,
• Daniel G. Rivera and
• Márcio W. Paixão

Beilstein J. Org. Chem. 2019, 15, 1210–1216, doi:10.3762/bjoc.15.118

• packing amount (wtot) was also determined by pycnometry. Porosity (εtot) of 0.67 is an optimal value for this material, which is according to the accepted values. One of the most important features of a microreactor for continuous-flow chemistry is the residence time (τ) which is known as the time in

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

• parameter was determined to be the rotational speed of the ball mill. At 200 rpm this led to a low SSA (7–66 m2g−1) due to an incomplete polymerization, while 800 rpm resulted in a medium SSA (600–820 m2g−1). This observation is hinting towards a partial degradation of the porosity by the high energy input

Application of olefin metathesis in the synthesis of functionalized polyhedral oligomeric silsesquioxanes (POSS) and POSS-containing polymeric materials

• Patrycja Żak and
• Cezary Pietraszuk

Beilstein J. Org. Chem. 2019, 15, 310–332, doi:10.3762/bjoc.15.28

• with some porosity [27]. Czaban-Jóźwiak and Grela have studied the metathetic transformation of allyl-substituted cubic silsesquioxane [28]. In search for the optimum catalyst a variety of ruthenium complexes were tested in the CM of allylsilsesquioxane with tert-butyl acrylate and (Z)-1,4-diacetoxybut

An overview on recent advances in the synthesis of sulfonated organic materials, sulfonated silica materials, and sulfonated carbon materials and their catalytic applications in chemical processes

• Hashem Sharghi,
• Pezhman Shiri and
• Mahdi Aberi

Beilstein J. Org. Chem. 2018, 14, 2745–2770, doi:10.3762/bjoc.14.253

• synthetic routes and catalytic applications [64]. The various properties including tunable porosity, stability, and surface chemistry of the carbon-based materials make the carbon-based materials appropriate for use in many catalytic transformations. In this regard, different functionalized carbon-based

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

• using cobalt-based metal complexes as reduction cocatalysts [17][18][19][20]. In these systems, structural properties of g-C3N4 such as specific surface area and porosity have a strong impact on activity, because they strongly affect the efficiency of electron/hole utilization to the surface chemical

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

• possess an extensive random network of nanochannels and nanocavities. Despite their apparently low porosity and surface area (as determined by BET techniques) [11][12][13], the possibility to load them with a guest up to an almost exhaustive occupancy of the cyclodextrin host units [12] indicates that

• [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

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

• , active pharmaceutical ingredients (APIs) or other bioactive organic molecules are used as building blocks for the framework [8]. Besides the advantages of MOFs as controlled delivery systems, BioMOFs have additional benefits, such as: i) porosity is no longer an issue as the release of the APIs or

Phosphonic acid: preparation and applications

• Charlotte M. Sevrain,
• Mathieu Berchel,
• Hélène Couthon and
• Paul-Alain Jaffrès

Beilstein J. Org. Chem. 2017, 13, 2186–2213, doi:10.3762/bjoc.13.219

• ) [69] or layered simple hydroxide (LSH) [70]. These materials prepared from phosphonic acids were assessed for numerus applications, including nuclear fuel stewardship and separations of actinides [71], porosity [72][73][74], bactericidal properties [75], inorganic salt release [76], luminescence [77