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

• does not seem to affect the domain size of LC very much. The phase transition concentrations from isotropic phase to biphasic state, ϕiso~bip, and from biphasic state to nematic phase, ϕbip~nem, were estimated by sigmoid curve fitting. The values were found to be 0.090 vol % and 0.17 vol

• %, respectively, as shown in Supporting Information File 1, Figure S3, which were lower than those previously obtained in the surfactant-assisted SWCNT aqueous dispersions [22][23]. Figure 2e shows the phase transition concentrations obtained in this study (L/D = 1378, red symbols) together with the previously

• obtained values for the SWCNT-SC dispersions (L/D = 1088 and = 665, black symbols) [22][23]. The Onsager theory predicts that the phase transition concentration for rod-like particles with aspect ratio L/D is ϕiso~bip = 3.34 D/L and ϕbip~nem = 4.49 D/L [24]. The L/D dependence of each phase transition

Inductive heating and flow chemistry – a perfect synergy of emerging enabling technologies

• Conrad Kuhwald,
• Sibel Türkhan and
• Andreas Kirschning

Beilstein J. Org. Chem. 2022, 18, 688–706, doi:10.3762/bjoc.18.70

• the surface, is called the skin-depth effect. It should be noted that this effect decreases significantly with increasing frequency. Two further parameters to be considered for inductively heated materials are the Curie temperature (TC) and the blocking temperature (TB). They mark the phase transition

Synthesis and bioactivity of pyrrole-conjugated phosphopeptides

• Qiuxin Zhang,
• Weiyi Tan and
• Bing Xu

Beilstein J. Org. Chem. 2022, 18, 159–166, doi:10.3762/bjoc.18.17

• , such as intracellular phase transition [22], molecular imaging [23][24][25][26][27][28][29][30][31][32][33], anisotropic hydrogels [34][35], targeting subcellular organelles [36][37][38][39][40], elimination of pluripotent stem cells (PSC) [41][42], and cancer therapy [43][44][45][46][47][48][49][50

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

• intermolecular hydrogen bonding changes, leading to variations on how hydrated the cryogel is, triggering a volume phase transition [34][35]. Changes in solubility can be described by the upper critical solution temperature (UCST) and lower critical solution temperatures (LCST). The UCST is the temperature at

• when introduced to the human body, and not degrade or dissolve straight away. Poly(N-isopropylacrylamide) (PNIPAM) is a well-known example of a thermo-responsive polymer, which exhibits a phase transition close to body temperature and has been used in cryogels to infer temperature responsive behaviour

In-depth characterization of self-healing polymers based on π–π interactions

• Josefine Meurer,
• Julian Hniopek,
• Johannes Ahner,
• Michael Schmitt,
• Jürgen Popp,
• Stefan Zechel,
• Kalina Peneva and
• Martin D. Hager

Beilstein J. Org. Chem. 2021, 17, 2496–2504, doi:10.3762/bjoc.17.166

• second phase transition of the PEG moieties observed in the DSC. Nevertheless, at 150 °C, P2 also shows the clear broadening of bands, which is consistent with the very similar positions for the perylene π–π interaction signal in the DSC. All these findings clearly support that at increased temperatures

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

• the thermodynamic concept for the phase transition of free polymer chains fails, when thermoresponsive polymers are assembled into such sterically confined architectures. Whereas many published studies focus on synthetic aspects as well as individual applications of thermoresponsive polymers, the

• representative. In contrast, for polymer arrangements with an upper critical solution temperature (UCST), there is only limited knowledge about preparation, application and precise physical understanding of the phase transition. This review article provides an overview about the current knowledge of

• , while polymers with an LCST type phase transition have been extensively studied over the past decades, interest in the equally promising but usually more complex and experimentally much less frequently observed UCST-based phase transitions of polymers has grown strongly in recent years. The UCST-type

Recent advances in palladium-catalysed asymmetric 1,4–additions of arylboronic acids to conjugated enones and chromones

• Jan Bartáček,
• Jan Svoboda,
• Martin Kocúrik,
• Jaroslav Pochobradský,
• Alexander Čegan,
• Miloš Sedlák and
• Jiří Váňa

Beilstein J. Org. Chem. 2021, 17, 1048–1085, doi:10.3762/bjoc.17.84

• catalyst precipitated and was recovered by centrifugation and discarding the supernatant liquid. This process was complicated by a low catalyst loading and high phase-transition temperature leading to the loss of mass during this procedure. The authors, however, did not try the preparation of a polymer

• with a lower phase-transition temperature. The loss of mass was compensated by the addition of 10% of fresh catalyst. By this method, they were able to reuse the catalyst in 6 cycles with only a very small decrease in the yield (98, >97, >97, >96, >95, >91%). Unfortunately, the enantioselectivity was

Tuning the solid-state emission of liquid crystalline nitro-cyanostilbene by halogen bonding

• Subrata Nath,
• Alexander Kappelt,
• Matthias Spengler,
• Bibhisan Roy,
• Jens Voskuhl and
• Michael Giese

Beilstein J. Org. Chem. 2021, 17, 124–131, doi:10.3762/bjoc.17.13

• groups employed halogen bonding for the formation of liquid crystalline materials [8][9]. For instance, Palacio et al. used (E)-1-(4-(octyloxy)phenyl)-2-(2,3,5,6-tetrafluoro-4-iodophenyl)diazene as a photo-switchable halogen bond donor and investigated the light-induced phase transition of the complexes

• the isotropic melt. Mesophase ranges are given in black numbers. POM images of the supramolecular assemblies NO2-C10∙∙∙F3Az (a), NO2-C10∙∙∙F2Az (b) and NO2-C10∙∙∙F2’Az (c) showing the phase transition upon cooling from the isotropic melt (I) to the nematic (N) or crystalline phase (Cr). Fluorescence

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

• and the ester alkyl chain length on the rheological properties of the reverse wormlike micelles in toluene was investigated in detail. Highly viscoelastic solutions were obtained even at a relatively low concentration of less than 1 wt %. The phase transition temperatures indicate that the formation

• Information File 1) shows the thermal reversibility of the gel formation process. The phase transition temperature can be obtained from the temperature sweeps and is defined as the temperature where the dynamic moduli intercept. In an alternative representation, the phase transition temperature can also be

• described as the temperature where the phase angle equals δ = 45°. According to Equation 1, the phase angle is defined as: The results of the phase transition temperatures obtained from the phase angles are summarized in Figure 3. The highest transition temperatures were found for the dirhamnolipid ester

Enzyme-instructed morphological transition of the supramolecular assemblies of branched peptides

• Dongsik Yang,
• Hongjian He and
• Bing Xu

Beilstein J. Org. Chem. 2020, 16, 2709–2718, doi:10.3762/bjoc.16.221

• ][20][21][22][23][24][25][26], as mimicry of amyloids [27], in the context of intracellular phase transition [28], and in molecular imaging [29][30]. Most of these studies are centered on peptide amphiphiles or amphiphilic peptides that are linear in geometry. Nature, however, also produces and

• molecular precursors for enzymatic self-assembly and phase transition. The morphological transformation of the negatively charged branched peptides in solution from micelles to nanofibers upon proteolysis suggests that it is feasible to explore other hydrophilic branches for branched peptides to undergo

Synthesis of organic liquid crystals containing selectively fluorinated cyclopropanes

• Zeguo Fang,
• Nawaf Al-Maharik,
• Peer Kirsch,
• Matthias Bremer,
• Alexandra M. Z. Slawin and
• David O’Hagan

Beilstein J. Org. Chem. 2020, 16, 674–680, doi:10.3762/bjoc.16.65

• and conditions: a) PPh3CH3Br, t-BuOK, diethyl ether, 0 °C to rt, 72% [17]; b) TMSCF3, NaI, THF, reflux; c) recrystallization, 27%. Phase transition temperatures of compounds 8–11. Physical properties of compounds 8–11. Supporting Information Supporting Information File 23: Experimental protocols and

The use of isoxazoline and isoxazole scaffolding in the design of novel thiourea and amide liquid-crystalline compounds

• Itamar L. Gonçalves,
• Rafaela R. da Rosa,
• Vera L. Eifler-Lima and
• Aloir A. Merlo

Beilstein J. Org. Chem. 2020, 16, 175–184, doi:10.3762/bjoc.16.20

• 18a–c. (i) SOCl2, reflux, 2 h; (ii) NH4SCN, acetone, reflux 40 minutes; (iii) acetone, reflux. Synthesis of amides. Part A: (i) SOCl2, reflux; (ii) KOCN, acetone, reflux; (iii) amines 3, 4, 8 and 9, acetone, reflux. Part B: (i) SOCl2, reflux; (ii) amine 4, acetone, reflux. Phase transition

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

• were used to investigate this behaviour. DSC measurements Phase transition temperature (Tt), melting temperatures (Ti) and enthalpy changes (∆Ht) of compounds 2 and 4 are summarized in Table 2. Based on the data given in Table 2, we found that fluorinated compounds present supplementary transition

• focal conic texture with unusually narrow ellipses of a SmA phase. Compound 4a presents a mosaic SmB phase where the molecules are organized in a hexagonal network as shown in Figure 2b. The low average of enthalpy value (1.89 J/g) given in Table 2 is due to the first order phase transition marked by

Synthesis of dipolar molecular rotors as linkers for metal-organic frameworks

• Sebastian Hamer,
• Fynn Röhricht,
• Marius Jakoby,
• Ian A. Howard,
• Xianghui Zhang,
• Christian Näther and
• Rainer Herges

Beilstein J. Org. Chem. 2019, 15, 1331–1338, doi:10.3762/bjoc.15.132

• fabrication of an array of dipolar rotors with a ferroelectric ground state and a Curie temperature above room temperature [30]. Such materials would have a number of exciting optical and electronic properties and applications such as signal processing and imaging. Phase transition from a stochastic to an

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

• continuous phases of CB[7] and PCL formed in the PCL/CB[7] nanofibers, which causes the formation of more crystal aggregates. DSC measurements can provide valuable information about the thermal transition properties, i.e., phase-transition temperatures and transition enthalpies. Figure 3 shows the first

• heating and cooling thermograms of neat PCL and electrospun PCL/CB[7] nanofibers. For comparison, the DSC curves of neat CB [7] and PCL are also provided (Figure S6 in Supporting Information File 1). Neat CB [7] has no strong and sharp peaks below 100 °C, indicating that there is no phase transition at

• temperatures (at around 41 °C). Tonelli et al. reported PCL/PCL-α-CD-IC nanofibers [17] and PCL/α-CD pseudorotaxane nanofibers [12] obtained by electrospinning. They found that the variations of phase-transition temperatures of nanofibers compared with those of neat PCL a) both, Tm and Tc of PCL/PCL-α-CD-IC

Evaluation of dispersion type metal···π arene interaction in arylbismuth compounds – an experimental and theoretical study

• Ana-Maria Preda,
• Małgorzata Krasowska,
• Lydia Wrobel,
• Philipp Kitschke,
• Phil C. Andrews,
• Jonathan G. MacLellan,
• Lutz Mertens,
• Marcus Korb,
• Tobias Rüffer,
• Heinrich Lang,
• Alexander A. Auer and
• Michael Mehring

Beilstein J. Org. Chem. 2018, 14, 2125–2145, doi:10.3762/bjoc.14.187

• intermolecular coordination [23][24]. Special attention was given to bismuth···π arene interaction by us including the formation of dimers and networks [1][25][26][27][28], and recently we reported a study on the effect of intermolecular dispersion type interaction on polymorphism and phase transition of

• crystals on this orthorhombic form 1b prior to this study [45]. Noteworthy, a phase transition of 1a to 1b does not occur before melting. The latest report on a polymorph of Ph3Bi was made by Stammler and Neumann, which submitted the crystallographic data of a monoclinic P21/c (1c) polymorph to the

Synthesis and supramolecular self-assembly of glutamic acid-based squaramides

• Juan V. Alegre-Requena,
• Marleen Häring,
• Isaac G. Sonsona,
• Alex Abramov,
• Eugenia Marqués-López,
• Raquel P. Herrera and
• David Díaz Díaz

Beilstein J. Org. Chem. 2018, 14, 2065–2073, doi:10.3762/bjoc.14.180

• concentrations and gel-to-sol transition temperatures were also determined for each case. In addition, the superior squaramide diester gelator was compared with an analogue triazole-based gelator in terms of critical gelation concentration, gelation kinetics and thermal phase transition. Keywords: glutamic acid

Nanoreactors for green catalysis

• M. Teresa De Martino,
• Loai K. E. A. Abdelmohsen,
• Floris P. J. T. Rutjes and
• Jan C. M. van Hest

Beilstein J. Org. Chem. 2018, 14, 716–733, doi:10.3762/bjoc.14.61

• in yields above 70%. Moreover, the Pd@PNIPAM nanoreactors could be easily recycled thanks to the reversible phase-transition of the polymeric brushes [112]. Que et al. reported the synthesis of gold nanoparticles (Au NPs) sheltered in PEG-PS nanogels for the reduction of 4-nitrophenol (4NP) [121

Correlation of surface pressure and hue of planarizable push–pull chromophores at the air/water interface

• Frederik Neuhaus,
• Fabio Zobi,
• Gerald Brezesinski,
• Marta Dal Molin,
• Stefan Matile and
• Andreas Zumbuehl

Beilstein J. Org. Chem. 2017, 13, 1099–1105, doi:10.3762/bjoc.13.109

• is a structural similarity between the flipper probes and cholesterol with both molecules being amphiphilic and flat. This called for a closer look at the influence of both molecules on phospholipid membrane organization (see Figure 4). For DPPC, the first-order phase transition between the

• disordered LE and the ordered LC phase can be identified as a plateau region in which the two phases are coexisting. The phase transition pressure amounts to ≈10 mN/m. Cholesterol has a fully condensed isotherm with low compressibility of the layer. The addition of flipper probes to DPPC does not influence

The synthesis of α-aryl-α-aminophosphonates and α-aryl-α-aminophosphine oxides by the microwave-assisted Pudovik reaction

• Erika Bálint,
• Ádám Tajti,
• Anna Ádám,
• István Csontos,
• Konstantin Karaghiosoff,
• Mátyás Czugler,
• Péter Ábrányi-Balogh and
• György Keglevich

Beilstein J. Org. Chem. 2017, 13, 76–86, doi:10.3762/bjoc.13.10

• subsequent NMR and theoretical study was also done for comparative purposes [62]. This latter work claims SS and RR dimers, which is obviously wrong, as the centrosymmetric dimers formed must be RS due to symmetry. The crystal structure of 5b does not undergo a phase transition at −100 ºC, hence, it must be

High performance p-type molecular electron donors for OPV applications via alkylthiophene catenation chromophore extension

• Paul B. Geraghty,
• Calvin Lee,
• Jegadesan Subbiah,
• Wallace W. H. Wong,
• James L. Banal,
• Mohammed A. Jameel,
• Trevor A. Smith and
• David J. Jones

Beilstein J. Org. Chem. 2016, 12, 2298–2314, doi:10.3762/bjoc.12.223

• observed, even these small changes in alkyl chain length result in a significant impact on the phase change behaviour. However, unfortunately no correlation can be made at this stage between subsequent thermal stability of OPV devices and the phase transition of the BXR and BTxR materials. Polarized

• optical microscopy (POM). POM was utilized in conjunction with a heating platform to directly observe these phase transitions and elucidate thin film structure. On heating at 10 °C·min−1 BQR shows a single phase transition to the isotropic melt at 202 °C, while on cooling we have identified an initial

Stimuli-responsive HBPS-g-PDMAEMA and its application as nanocarrier in loading hydrophobic molecules

• Yongsheng Chen,
• Li Wang,
• Haojie Yu,
• Zain-Ul-Abdin,
• Ruoli Sun,
• Guanghui Jing,
• Rongbai Tong and
• Zheng Deng

Beilstein J. Org. Chem. 2016, 12, 939–949, doi:10.3762/bjoc.12.92

• aggregates were capable to encapsulate small hydrophobic molecules. These newly prepared HBPS-g-PDMAEMA nanocarriers might be used in, e.g., medicine or catalysis. Keywords: amphiphilic polymer; hyperbranched polystyrene; phase transition; poly[2-(dimethylamino)ethyl methacrylate] (PDMAEMA); stimuli

• aggregates stability in aqueous solution. The PDMAEMA segments behaved as functional chains to afford stimuli-responsive properties. The phase-transition behavior of the polymer aggregates in aqueous solution was studied. The size of the polymer aggregates under different conditions (polymer concentration

• reached a stable value at 40 °C. The curve of the first derivative showed that the transmittance decreased dramatically at a temperature of about 39 °C, which is the LCST of HBPS-g-PDMAEMA in water at a concentration of 10 mg/mL. Figure 2B shows the phase transition of HBPS-g-PDMAEMA in water. When the

Syntheses of dibenzo[d,d']benzo[2,1-b:3,4-b']difuran derivatives and their application to organic field-effect transistors

• Minh Anh Truong and
• Koji Nakano

Beilstein J. Org. Chem. 2016, 12, 805–812, doi:10.3762/bjoc.12.79

• organic solvents and can be purified by column chromatography. In contrast, because of low solubility in common organic solvents, the crude product of syn-DNBDF 6 was purified by washing several times with water and the subsequent sublimation. Thermal properties The phase-transition properties and thermal

• stability of syn-DBBDF 5 and syn-DNBDF 6 were evaluated by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA), respectively. The DSC scans of syn-DBBDF 5 and syn-DNBDF 6 showed some transition peaks with the first phase-transition temperature at 20 °C and 45 °C, respectively, in

• the heating process (Figure 2a). Such phase-transition temperatures are >50 °C lower than those of their anti-isomers 3 and 4 [38][39]. These results indicate that syn-DBBDF 5 and syn-DNBDF 6 form weaker intermolecular interactions in the solid state than their corresponding anti-isomers. The

Synthesis of photoresponsive cholesterol-based azobenzene organogels: dependence on different spacer lengths

• Yuchun Ren,
• Bin Wang and
• Xiuqing Zhang

Beilstein J. Org. Chem. 2015, 11, 1089–1095, doi:10.3762/bjoc.11.122

• calorimetry (DSC). The DSC curves of the cholesterol-based supramolecular complexes are shown in Figure 2 and phase transition temperatures are listed in Table 1. The DSC thermogram of M0 presented three peaks at 158, 211 and 249 °C on heating, corresponding to the crystal to crystal transition, crystal to

• with both solvents are very stable for months of storage in a closed container, and no significant changes can be found. However, upon UV irradiation, the gel to sol phase transition became transparent as a result of trans-to-cis isomerization. Moreover, the solution has a tendency to reverse the sol

• to gel phase transition under visible irradiation. The corresponding visual images are shown in Figure 3. Scanning electron microscopy studies To obtain a visual insight into the morphology of the aggregation mode, the typical structures of the xerogels prepared by the freeze-drying of the three gels

Carboxylated dithiafulvenes and tetrathiafulvalene vinylogues: synthesis, electronic properties, and complexation with zinc ions

• Yunfei Wang and
• Yuming Zhao

Beilstein J. Org. Chem. 2015, 11, 957–965, doi:10.3762/bjoc.11.107

• illustrated in Figure 6. The DSC data of Zn-TTFV 8 (Figure 6A) manifested very good thermal stability up to 400 °C, without any significant melting or decomposition except a slight phase transition at 272 °C. Comparatively, the DSC trace of carboxyl-TTFV ligand 6 showed a distinctive melting process at 317 °C