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

• concentration of the dispersion, the materials of the substrate [34], and the viscosity of the dispersions should be adjusted. For instance, Headrick et al. fabricated highly aligned films by immersing the substrate in a solidifying solution immediately after the SWCNTs were aligned by applying shear stress to

• consistent with the Onsager theory. On the other hand we found that the order parameter of the DWCNT film, obtained from the LC dispersion, was nearly identical to that of the film composed of lower L/D SWCNTs [23]. Further optimization of experimental conditions, including viscosity of the dispersion and

• with previous studies [22][23]. Initially, 100 mg of DWCNT powder was pre-dispersed in 100 mL of Wako glycerol with a stirrer (ASONE, HPS-100PD) rotating at 500 rpm for 18 hours. During the stirring, the DWCNTs were defibrated by the shear stress of the high-viscosity glycerol [36]. After suspension in

Studying specificity in protein–glycosaminoglycan recognition with umbrella sampling

• Mateusz Marcisz,
• Sebastian Anila,
• Margrethe Gaardløs,
• Martin Zacharias and
• Sergey A. Samsonov

Beilstein J. Org. Chem. 2023, 19, 1933–1946, doi:10.3762/bjoc.19.144

• functions results principally from their unique physicochemical and structural features, including high negative charge, high viscosity and lubrication propensities, unbranched polysaccharide structures, low compressibility as well as the ability to attract and imbibe large amounts of water [17]. Unlike

Radical chemistry in polymer science: an overview and recent advances

• Zixiao Wang,
• Feichen Cui,
• Yang Sui and
• Jiajun Yan

Beilstein J. Org. Chem. 2023, 19, 1580–1603, doi:10.3762/bjoc.19.116

• optionally, a chain-transfer agent [21]. Products obtained from bulk polymerization have high optical clarity and are usually very pure [2]. The mechanism and equipment are relatively simple for a large-scale production in a short time. However, heat and mass transfer become difficult as the viscosity of the

• polymerization. The use of a solvent can lower the viscosity of the polymerization system, leading to better mass and heat transfer. Good heat transfer can reduce the Trommsdorff–Norrish effect [22]. Meanwhile, the inhibited termination reactions cause a significant increase in the overall yield

• dissolved initiators in the liquid phase during the process. A suspending agent, e.g., polyvinyl alcohol (PVA), is added to the system to prevent coalescence. The viscosity in suspension polymerization is low throughout the process which brings good heat transfer and temperature control, and therefore well

Synthesis of 5-arylidenerhodanines in L-proline-based deep eutectic solvent

• Stéphanie Hesse

Beilstein J. Org. Chem. 2023, 19, 1537–1544, doi:10.3762/bjoc.19.110

• potential environmental impacts [14]. For a synthetic purpose, the melting point of the DES and its viscosity are key parameters for the convenience of their use. Indeed, DES viscosities are generally higher than those of water and other common organic solvents and a too high viscosity can act as an

• characterized; a pH value of 10.07 was measured at 30 °C by Shah et al. [16] and a viscosity of 750 cP at 25 °C was reported by Mjalli et al. [17] (Table 1). It remains today one of the most used DES and studies on it are still conducted [14]. ChCl/glycerol (ChCl/Gly; 1:2) is another classical DES with a

• melting point of 17 °C which is more acidic and less viscous than ChCl/urea [18][19] (Table 1). In addition, proline-based natural deep eutectic solvents (NaDES) were also studied and it was shown that they presented higher viscosity values than the ChCl-based NaDES, suggesting that the HBA used for the

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

• (Figure 2b). Interestingly, the viscosity of the gels was progressively reduced due to the decrease of the physical entanglement of the polymeric chains via photodegradation. Thus, the viscoelasticity of the rotaxane-based gels could be fine-tuned by modifying the irradiation time. This visible-light

pH-Responsive fluorescent supramolecular nanoparticles based on tetraphenylethylene-labelled chitosan and a six-fold carboxylated tribenzotriquinacene

• Nan Yang,
• Yi-Yan Zhu,
• Wei-Xiu Lin,
• Yi-Long Lu and
• Wen-Rong Xu

Beilstein J. Org. Chem. 2023, 19, 635–645, doi:10.3762/bjoc.19.45

• of deacetylation greater than 95% (viscosity 100, 200 mPa·s) was purchased from Aladdin. All other reagents and solvents were purchased from Xilong Science as analytical grade and were used without further purification. TBTQ-C6 and TPE-CHO were synthesized and purified according to the previously

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

• technologies [23] or phytoremediation [24]. When chitosan and saponins are mixed, their foamability properties change, leading to a longer foam stability due to the higher viscosity achieved [25]. The use of chitosan to absorb saponins have been studied for different purposes. A high specific area activated

• of both lines gives us an approximate optimal foamability for a saponin concentration value of ca. 0.3%. These measurements correspond to solutions prepared using deionized water. Other factors such as the viscosity due to the polysaccharides or the ionic strength contributed by the catalyst can

• of LBG impacts the stability of the foam in a remarkable way. Finally, the solutions of xanthan are not shown in Figure 1, because their foams are very stable due to the much higher viscosity of those solutions. In fact, the liquid fraction was not even falling down, and liquid agglomeration began to

Inline purification in continuous flow synthesis – opportunities and challenges

• Jorge García-Lacuna and
• Marcus Baumann

Beilstein J. Org. Chem. 2022, 18, 1720–1740, doi:10.3762/bjoc.18.182

• the examples involve the separation of an organic phase from an aqueous one. However, two immiscible organic phases might be separated, like in the case of methanol and dodecane [49]. Solvent properties such as viscosity, interfacial tension, or salt concentrations in case of aqueous mixtures are some

On Reuben G. Jones synthesis of 2-hydroxypyrazines

• Pierre Legrand and
• Yves L. Janin

Beilstein J. Org. Chem. 2022, 18, 935–943, doi:10.3762/bjoc.18.93

• syringe injector, these slow additions were undertaken by using a syringe fitted with its 0.8 mm needle but devoid of its piston so that the rate of the addition was governed solely by gravity and the viscosity of the solution added. Thus, the addition of 5.5 mL of a 6 N solution of sodium hydroxide took

Adjusting the length of supramolecular polymer bottlebrushes by top-down approaches

• Tobias Klein,
• Franka V. Gruschwitz,
• Maren T. Kuchenbrod,
• Ivo Nischang,
• Stephanie Hoeppener and
• Johannes C. Brendel

Beilstein J. Org. Chem. 2021, 17, 2621–2628, doi:10.3762/bjoc.17.175

• , and η is the viscosity of the solvent [36]. By assuming typical values for the wall velocity, bubble radius, and viscosity of the solvent, the equation simplifies [37][38] to We exposed the BTU and BTP fibers to extended US (>1 h). No further scission could be observed after 2–3 h of US. AF4–MALLS

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

• of the size, porosity, and geometry of the final product tailored to the requirements of the individual patient, e.g., potential scaffold fabrication from cryogels in tissue engineering [63]. It is extremely important to consider the viscosity and injectability of the material for limitations on

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

• their physicochemical properties (e.g., solubility, viscosity) and can respond to stimuli in several ways by altering light transmitting abilities, shape, color, conductivity, as well as wettability [27][28]. Therefore, such functional polymers have a huge potential in numerous areas of application

• low viscosity, high density of polymer segments and functional groups as well as a smaller hydrodynamic radius and larger diffusion coefficient compared to linear polymer chains in solution. Amphiphilic AB-type copolymers spontaneously form micelle structures above a critical concentration by self

Recent advances in the application of isoindigo derivatives in materials chemistry

• Andrei V. Bogdanov and
• Vladimir F. Mironov

Beilstein J. Org. Chem. 2021, 17, 1533–1564, doi:10.3762/bjoc.17.111

• efficiency values of 7.3%. The problem of the low solubility of such polymers was partially solved by inserting an alkylene spacer between two thiophene fragments in one of the monomer units [44]. Efficiency (3.0–3.7%) and viscosity characteristics provide good prerequisites for the use of this type of

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

• design a specific range of operation and often a very specific window of optimal pumping efficiency (flow rate, pressure drop and viscosity) within this domain. Hence, especially when considering the concepts of direct scale-up this becomes an increasingly important aspect. Examples of flow systems

Nitroalkene reduction in deep eutectic solvents promoted by BH₃NH₃

• Chiara Faverio,
• Monica Fiorenza Boselli,
• Patricia Camarero Gonzalez,
• Alessandra Puglisi and
• Maurizio Benaglia

Beilstein J. Org. Chem. 2021, 17, 1041–1047, doi:10.3762/bjoc.17.83

• is a nontoxic, biodegradable and nonflammable solvent for which no special handling or storage precautions are required [19]. Some limits, such as high viscosity and low solubility of highly hydrophobic compounds and possible side reactions due to the presence of hydroxy groups, can be overcome by

Synthesis of 10-O-aryl-substituted berberine derivatives by Chan–Evans–Lam coupling and investigation of their DNA-binding properties

• Peter Jonas Wickhorst,
• Mathilda Blachnik,
• Denisa Lagumdzija and
• Heiko Ihmels

Beilstein J. Org. Chem. 2021, 17, 991–1000, doi:10.3762/bjoc.17.81

• low fluorescence quantum yields are caused by conformational changes in the excited state, the fluorescence was recorded in media with different viscosity, namely in glycerol at different temperatures (Figure 2, Figure S2, Supporting Information File 1). It was observed that the derivatives 5a–e have

• deactivation of the excited state by conformational changes, e.g., torsional relaxation [42][43]. Since the fluorescence quantum yield of the parent berberine (1a) does not correlate well with the viscosity of the medium [40], it was concluded that the weak light-up effect in glycerol is mainly caused by the

• suppressed rotation about the Ar–O bond. Nevertheless, as the emission quantum yield of the derivatives 5a–e still remained low, even at high viscosity of the medium, there obviously exist additional relaxation pathways in the excited state, most likely a photo-induced electron transfer (PET) from the 10

Supramolecular polymers with reversed viscosity/temperature profile for application in motor oils

• Jan-Erik Ostwaldt,
• Christoph Hirschhäuser,
• Stefan K. Maier,
• Carsten Schmuck and
• Jochen Niemeyer

Beilstein J. Org. Chem. 2021, 17, 105–114, doi:10.3762/bjoc.17.11

• , 64293 Darmstadt, Germany 10.3762/bjoc.17.11 Abstract We report novel supramolecular polymers, which possess a reversed viscosity/temperature profile. To this end, we developed a series of ditopic monomers featuring two self-complementary binding sites, either the guanidiniocarbonyl pyrrole carboxylic

• concentration of the solution and on the polarity of the solvent. This effect can counteract the loss of viscosity of the solvent at elevated temperatures, thus opening an application of our systems as viscosity index improvers (VIIs) in working fluids. This was tested for different motor oils and led to the

• identification of one compound as a promising VII. Keywords: noncovalent interactions; polymers; ring-chain transformation; supramolecular chemistry; viscosity; Introduction Viscosity index improvers (VIIs) are used to counteract the loss of viscosity of working fluids (such as motor oils) at elevated

Dirhamnolipid ester – formation of reverse wormlike micelles in a binary (primerless) system

• David Liese,
• Hans Henning Wenk,
• Xin Lu,
• Jochen Kleinen and
• Gebhard Haberhauer

Beilstein J. Org. Chem. 2020, 16, 2820–2830, doi:10.3762/bjoc.16.232

• hydrophobic groups are oriented towards the solvent. One structure which can be formed by surfactants are so-called wormlike micelles, that are characterized by a high anisotropic structure. These micelles can, if the concentration and dynamics of the surfactant micelles is right, build viscosity since the

• ) gradually declines with increasing temperatures, indicating a reduction in the length of the micelles. Consequently, the shortened micelle lengths lead to a low-viscosity material at higher temperatures. The variations of G''min/G0, η0, and τR depending on the temperature are shown in Figure 7 as an

• . Rheological values obtained from the oscillatory-shear experiments for the dirhamnolipid ethyl ester 2/toluene (0.5 wt %) system at different temperatures. Supporting Information Supporting Information File 524: Synthesis of the compounds and additional Figures and Tables (viscosity). Acknowledgements The

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

• with LED strips. A pneumatic nebulizer was used. The droplet diameter was reported by the nebulizer supplier as 6 µm for water-based solutions. The droplet size depends on the surface tension and viscosity of the liquid and the pressure of the gas. Therefore, it might be different for different

• the diffusivity, kinematic viscosity, reactor volume, stirrer speed, etc. For a laminar flow in microstructured reactors, the characteristic mixing time can be calculated by the Einstein–Smoluchovski equation (Equation 6). Due to the short diffusion distances, complete mixing can be achieved rapidly

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

Oligomeric ricinoleic acid preparation promoted by an efficient and recoverable Brønsted acidic ionic liquid

• Fei You,
• Xing He,
• Song Gao,
• Hong-Ru Li and
• Liang-Nian He

Beilstein J. Org. Chem. 2020, 16, 351–361, doi:10.3762/bjoc.16.34

• and green preparation processes are the two key features for the development of green products. As a bio-lubricant in metalworking fluids, estolides of ricinoleic acid are considered as the promising substitute to mineral oil with a favorable viscosity and viscosity index. Thus, an efficient and

• used as lubricant for metal cutting oils due to its appropriate viscosity, good adsorptivity and film formation ability on metal surfaces. Furthermore, the biodegradability of these estolides in the environment makes them attractive as green products. In parallel with the increasing demand for high

• changing the reaction time at 190 °C and 50 kPa with 15 wt % IL as catalyst. The viscosity characterization showed the product derived from 6 h of reaction, whose acid value is 51 mg KOH/g and the corresponding average oligomerization degree is 4, meets the requirement of lubricant additive index. Notably

p-Pyridinyl oxime carbamates: synthesis, DNA binding, DNA photocleaving activity and theoretical photodegradation studies

• Panagiotis S. Gritzapis,
• Panayiotis C. Varras,
• Nikolaos-Panagiotis Andreou,
• Katerina R. Katsani,
• Konstantinos Dafnopoulos,
• George Psomas,
• Zisis V. Peitsinis,
• Alexandros E. Koumbis and
• Konstantina C. Fylaktakidou

Beilstein J. Org. Chem. 2020, 16, 337–350, doi:10.3762/bjoc.16.33

• cause of the activity. Therefore, the interaction of selected compounds, i.e., 11 and 12, with CT DNA was monitored by UV–vis spectroscopy and viscosity measurements. Additionally, the EB−displacing ability of the compounds was evaluated by fluorescence emission spectroscopy. The UV–vis spectra of a CT

• collected, i.e., DNA-viscosity measurements [70]. Thus, the monitoring of the DNA viscosity changes when compounds 11 and 12 are present, may be elucidating in regard to their binding mode to DNA. As known, the changes of the relative DNA viscosity (η/ηo)1/3 are proportionally related to changes of the

• relative DNA length (L/L0) [71]. Having this relation in mind, the viscosity of a CT DNA solution (0.1 mM) was determined (Figure 3) in the presence of increasing amounts of compounds 11 and 12 (up to the value of r = 0.35). For compound 11 the DNA viscosity increases in the presence of the compound. For

Synthesis, liquid crystalline behaviour and structure–property relationships of 1,3-bis(5-substituted-1,3,4-oxadiazol-2-yl)benzenes

• Afef Mabrouki,
• Malek Fouzai,
• Armand Soldera,
• Abdelkader Kriaa and
• Ahmed Hedhli

Beilstein J. Org. Chem. 2020, 16, 149–158, doi:10.3762/bjoc.16.17

• in organic chemistry [3]. The C–F bond is highly polarized and this polarity inhibits the lone pair donation from fluorine, making this element a weak coordinator. These properties are the basis for the unique properties of perfluoroalkylated compounds such as high viscosity, high density, high

• lead on a deep study in order to investigate other parameters such as response time, viscosity and dielectric anisotropy. DSC thermograms of fluorinated compounds 2b, 4a and 4b recorded at 5 °C/mn at heating (down traces) and cooling (top traces) cycles. Optical texture (×10) of liquid crystal phase

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

• loadings influences the morphology and AFD of the resulting electrospun nanofibers. The variations in AFD of the PCL/CB[7] nanofibers are attributed to differences in electrical conductivity and viscosity of the polymer solutions [13][14][15]. FTIR spectroscopy is a frequently used and effective method to

Synthesis and fluorescent properties of N(9)-alkylated 2-amino-6-triazolylpurines and 7-deazapurines

• Andrejs Šišuļins,
• Jonas Bucevičius,
• Yu-Ting Tseng,
• Irina Novosjolova,
• Kaspars Traskovskis,
• Ērika Bizdēna,
• Huan-Tsung Chang,
• Sigitas Tumkevičius and
• Māris Turks

Beilstein J. Org. Chem. 2019, 15, 474–489, doi:10.3762/bjoc.15.41

• solvent properties such as viscosity or hydrogen bonding. Interestingly, purine class compound 8c showed a dual-fluorescence character in the solvents of higher polarity (DMSO, MeCN) arising from the locally excited and charge transfer excited states, however, dual-fluorescence was not evident for the 7

• excited states are environment-dependent it makes these fluorophores interesting as potential sensors of the surroundings such as polarity or (micro)viscosity sensors. Other purine and 7-deazapurine derivatives, which efficiently emit light in the blue region with respect to the structural