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Search for "thermal stability" in Full Text gives 238 result(s) in Beilstein Journal of Organic Chemistry. Showing first 200.

Highly bulky and stable geometry-constrained iminopyridines: Synthesis, structure and application in Pd-catalyzed Suzuki coupling of aryl chlorides

  • Yi Lai,
  • Zhijian Zong,
  • Yujie Tang,
  • Weimin Mo,
  • Nan Sun,
  • Baoxiang Hu,
  • Zhenlu Shen,
  • Liqun Jin,
  • Wen-hua Sun and
  • Xinquan Hu

Beilstein J. Org. Chem. 2017, 13, 213–221, doi:10.3762/bjoc.13.24

Graphical Abstract
  • iminopyridylpalladium chlorides were developed. The steric environment adjacent to the nitrogen atom in the pyridine rings and diimine parts enhanced the thermal stability of the palladium species. Bulkier groups at the imino group stabilized the palladium species and the corresponding palladium chlorides showed high
  • under high temperature, if the palladium catalyst is stable enough. The formation of palladium black was observed in reactions of aryl chlorides using the reported palladium catalyst system, which inspired us to improve the thermal stability of the palladium complex. The steric environment adjacent to
  • the nitrogen in pyridine rings and diimine parts enhanced the thermal stability of metal species, albeit under harsh conditions [65][66][67][68]. Therefore, Figure 1 schematically illustrates various substituents of iminopyridines constraining the geometrical influence around the palladium center. In
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Published 03 Feb 2017

A postsynthetically 2’-“clickable” uridine with arabino configuration and its application for fluorescent labeling and imaging of DNA

  • Heidi-Kristin Walter,
  • Bettina Olshausen,
  • Ute Schepers and
  • Hans-Achim Wagenknecht

Beilstein J. Org. Chem. 2017, 13, 127–137, doi:10.3762/bjoc.13.16

Graphical Abstract
  • first report [21]. The orientation of the 2’-OH group in the arabino configuration towards the major groove yields hybrids with RNA that show a slightly lower thermal stability compared to DNA/RNA hybrids. In order to evaluate this structural influence for our fluorescently labelled oligonucleotides, we
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Published 20 Jan 2017

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

Graphical Abstract
  • are not bound to any carboxlic acids and may therefore be removable upon activation. In order to elaborate on the materials properties, we synthesized HFF-3 in bulk amounts and studied the thermal stability and sorption properties of this framework. The framework crystallizes as anisotropic needles
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Published 02 Jan 2017

Interactions between cyclodextrins and cellular components: Towards greener medical applications?

  • Loïc Leclercq

Beilstein J. Org. Chem. 2016, 12, 2644–2662, doi:10.3762/bjoc.12.261

Graphical Abstract
  • group of Yamamoto studied the effect of β-, γ-, G1-β-, and Me-α-CD on the thermal stability of an aqueous buffered solution of chicken egg white lysozyme by circular dichroism and fluorescence spectroscopy [91]. The thermal stability is significantly lowered in the presence of β-, γ-, and G1-β-CD
  • whereas the opposite is true for the Me-α-CD. It should be noted that the thermal stability reduction is very important for G1-β-CD. Based on fluorescence spectroscopy, the authors suggested that CDs include the side chains of tryptophan (Trp) residues of lysozyme within their internal cavities to
  • diminish the hydrophobicity of the hydrophobic core of lysozyme and consequently to lower the thermal stability (Scheme 3). In addition, some CD molecules persist in binding to the side chains of Trp residues to retard the renaturation of lysozyme. From the findings described above, it can be presumed that
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Published 07 Dec 2016

Synthesis of three-dimensional porous hyper-crosslinked polymers via thiol–yne reaction

  • Mathias Lang,
  • Alexandra Schade and
  • Stefan Bräse

Beilstein J. Org. Chem. 2016, 12, 2570–2576, doi:10.3762/bjoc.12.252

Graphical Abstract
  • 650 m²/g. Those networks also showed a high thermal stability as well as insolubility in common organic solvents. Keywords: three-dimensional; porous hyper-crosslinked polymers; thiol–yne; Introduction The synthesis of different organic networks has been previously reported. Among them, especially
  • analyses (Table 1) of networks 3 and 5 showed equimolar turnover regarding the number of functional groups of the monomers. Further, TGA measurements showed a high thermal stability of the HCPs. The TGA curves of HCP 3 and 5 are shown in Supporting Information File 1, Figures S5 and S6. The SEM pictures
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Published 29 Nov 2016

Inhibition of peptide aggregation by means of enzymatic phosphorylation

  • Kristin Folmert,
  • Malgorzata Broncel,
  • Hans v. Berlepsch,
  • Christopher H. Ullrich,
  • Mary-Ann Siegert and
  • Beate Koksch

Beilstein J. Org. Chem. 2016, 12, 2462–2470, doi:10.3762/bjoc.12.240

Graphical Abstract
  • structure of KFM6. The nonpolar leucine residues at positions a and d contribute to thermal stability by hydrophobic core packing of the leucine zipper motif (“knobs-into-holes principle”). Charged amino acids at positions e, g, b, and c stabilize the coiled-coil by intramolecular electrostatic attractions
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Published 18 Nov 2016

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

Graphical Abstract
  • route to facilitate translation to printing programs? Structure–property relationships: Can we modify the BTR chromophore length or alkyl side-chain length thereby improving device thermal stability and device performance? We report here a simplified synthetic route to a series of BTR analogues (Figure
  • the BXR and BTxR series has been studied by TGA and DSC. All of the materials show good thermal stability with <5% weight loss below 390 °C, see Supporting Information File 1, Figure S5.1. The phase behaviour was examined by DSC (see Supporting Information File 1, Figure S6.1 for full details) with a
  • 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
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Published 02 Nov 2016

Robust C–C bonded porous networks with chemically designed functionalities for improved CO2 capture from flue gas

  • Damien Thirion,
  • Joo S. Lee,
  • Ercan Özdemir and
  • Cafer T. Yavuz

Beilstein J. Org. Chem. 2016, 12, 2274–2279, doi:10.3762/bjoc.12.220

Graphical Abstract
  • the monomers is essential since the porosity, a desired feature, is best achieved by structurally interlocked motifs. In industrial applications, porous polymers have to meet several important criteria like high porosity, chemical and thermal stability while also possessing application-specific
  • functionalities [1][2]. Designing and synthesizing structures that respect all these criteria is a challenging task. Chemical and thermal stability can be achieved best by having robust C–C bonded architecture like in porous polymer networks (PPNs) [3], porous aromatic frameworks (PAFs) [4] or conjugated
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Published 28 Oct 2016

Comparing blends and blocks: Synthesis of partially fluorinated diblock polythiophene copolymers to investigate the thermal stability of optical and morphological properties

  • Pierre Boufflet,
  • Sebastian Wood,
  • Jessica Wade,
  • Zhuping Fei,
  • Ji-Seon Kim and
  • Martin Heeney

Beilstein J. Org. Chem. 2016, 12, 2150–2163, doi:10.3762/bjoc.12.205

Graphical Abstract
  • , suggesting that such materials may be interesting for enhanced thermal stability of organic photovoltaic active layers based on similar systems. Keywords: conjugated block-copolymer synthesis; fluorination; microphase stabilization; polythiophene; temperature-dependent Raman spectroscopy; Introduction With
  • collection. With the thermal stability of all-polymer and polymer-fullerene blend microstructures being particularly problematic [19], block copolymers present a potential solution. Indeed, it has been shown that when block copolymers are used as additives in bulk heterojunction donor–acceptor blend layers
  • , but critically increases the thermal stability of intramolecular order, as observed by temperature dependent Raman spectroscopy studies. Results and Discussion Synthesis The monomers and homopolymers P3OT and F-P3OT were synthesized via KCTP from the activated monomers 2 and 4, as reported in our
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Published 10 Oct 2016

Synthesis and characterization of fluorinated azadipyrromethene complexes as acceptors for organic photovoltaics

  • Forrest S. Etheridge,
  • Roshan J. Fernando,
  • Sandra Pejić,
  • Matthias Zeller and
  • Geneviève Sauvé

Beilstein J. Org. Chem. 2016, 12, 1925–1938, doi:10.3762/bjoc.12.182

Graphical Abstract
  • structure is fluorine, which is a unique element due to its small size and high electronegativity, with many applications in pharmaceuticals and materials [13][14][15]. Its use as a hydrogen replacement has garnered wide use in industrial applications for high thermal stability and surface effects, most
  • spectroscopy, MALDI–TOF–MS and elemental analysis. In the case of L2, the pure BF2+ chelate could not be isolated by column chromatography, and will therefore be omitted from further analysis. The thermal stability of the zinc(II) complexes was examined by thermal gravity analysis and the results are shown in
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Published 29 Aug 2016

Experimental and theoretical investigations on the high-electron donor character of pyrido-annelated N-heterocyclic carbenes

  • Michael Nonnenmacher,
  • Dominik M. Buck and
  • Doris Kunz

Beilstein J. Org. Chem. 2016, 12, 1884–1896, doi:10.3762/bjoc.12.178

Graphical Abstract
  • prepared the respective selenourea, the 77Se NMR chemical shift was not reported [39][47][48]. We showed that the tert-butyl substituted dipyridocarbene dipiytBu exhibits an unusual high thermal stability and proofed the alternating bond lengths in the conjugated π-system of this carbene (similar to
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Published 23 Aug 2016

On the cause of low thermal stability of ethyl halodiazoacetates

  • Magnus Mortén,
  • Martin Hennum and
  • Tore Bonge-Hansen

Beilstein J. Org. Chem. 2016, 12, 1590–1597, doi:10.3762/bjoc.12.155

Graphical Abstract
  • half-lives. The experimental results are supported by DFT calculations, and we provide a possible explanation for the reduced thermal stability of ethyl halodiazoacetates compared to ethyl diazoacetate and for the relative decomposition rates between the chloro, bromo and iodo analogs. We have also
  • briefly studied the thermal, non-catalytic cyclopropanation of styrenes and compared the results to the analogous Rh(II)-catalyzed reactions. Keywords: carbenes; catalysis; cyclopropanation; halo diazoacetates; half-lives; thermal stability; Introduction The chemistry of diazo compounds has fascinated
  • ]. The synthesis and properties of diazo compounds have been a topic of much interest, particularly relevant are their thermal stability and sensitivity towards Brønsted and Lewis acids. The monograph by Regitz and Maas gives an excellent overview on their preparation and properties [3]. The thermal
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Published 26 Jul 2016

Star-shaped and linear π-conjugated oligomers consisting of a tetrathienoanthracene core and multiple diketopyrrolopyrrole arms for organic solar cells

  • Hideaki Komiyama,
  • Chihaya Adachi and
  • Takuma Yasuda

Beilstein J. Org. Chem. 2016, 12, 1459–1466, doi:10.3762/bjoc.12.142

Graphical Abstract
  • cross-coupling reaction. Both TTA-DPP4 and TTA-DPP2 were soluble in common organic solvents, such as chloroform, toluene, and chlorobenzene. The thermal stability of these compounds was analyzed by thermogravimetric analysis (TGA). As shown in Figure 3, the 5% weight-loss temperature of TTA-DPP4 and TTA
  • -DPP2, under N2 atmosphere, was determined to be 378 and 380 °C, respectively, suggesting the high thermal stability for these compounds as donor materials. Optical properties The UV–vis absorption spectra of TTA-DPP4 and TTA-DPP2 in chloroform solutions and as-spun thin films are depicted in Figure 4
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Published 14 Jul 2016

Mutagenic activity of quaternary ammonium salt derivatives of carbohydrates

  • Barbara Dmochowska,
  • Karol Sikora,
  • Anna Woziwodzka,
  • Jacek Piosik and
  • Beata Podgórska

Beilstein J. Org. Chem. 2016, 12, 1434–1439, doi:10.3762/bjoc.12.138

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  • interesting group of QASs. These are extensively explored worldwide and find many applications. Because of their unique properties, including low melting point (by definition below 100 °C), high conductivity, high thermal stability, low flammability, and very low (if any) volatility [14], they are called
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Published 12 Jul 2016

The role of alkyl substituents in deazaadenine-based diarylethene photoswitches

  • Christopher Sarter,
  • Michael Heimes and
  • Andres Jäschke

Beilstein J. Org. Chem. 2016, 12, 1103–1110, doi:10.3762/bjoc.12.106

Graphical Abstract
  • substitution pattern, diarylethenes with one alkyl group can exhibit significant photochromism, but they generally show poor stability towards extended UV irradiation, low thermal stability, and decreased fatigue resistance. The results obtained provide an important direction for the design of new efficient
  • cyclopentenyl bridge, which may also be perfluorinated. Substituents on the aryl rings tune the photophysical and chemical properties, such as absorption and isomerization wavelengths, thermal stability, and fatigue resistance. In 2010 our group reported the first diarylethene-based photoswitchable nucleosides
  • hybridization upon switching [43][44]. This new class of diarylethenes showed promising photophysical and photochemical properties, such as the location of the photostationary states, reversibility of switching, thermal stability, and fatigue resistance. In 2013 we developed a 2nd generation of diarylethene
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Published 01 Jun 2016

Synthesis of 2,1-benzisoxazole-3(1H)-ones by base-mediated photochemical N–O bond-forming cyclization of 2-azidobenzoic acids

  • Daria Yu. Dzhons and
  • Andrei V. Budruev

Beilstein J. Org. Chem. 2016, 12, 874–881, doi:10.3762/bjoc.12.86

Graphical Abstract
  • -position of the benzisoxazole dramatically reduces the thermal stability of these compounds. Indeed, these compounds are the most labile representatives of several isomeric oxazoles [32], and they begin to decompose at temperatures slightly above 30 °C, which limits the number of methods for their
  • (Table 2). The desired products 2b–f were isolated in moderate to high yields (Table 2). Both electron-withdrawing groups (Cl, Br, I) and the electron-donating group (triphenylmethyl) were well-tolerated. The thermal stability of the products of 2 decreases in the series: 2f > 2a > 2e > 2d > 2c > 2b
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Published 04 May 2016

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

Graphical Abstract
  • 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
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Published 26 Apr 2016

Highly stable and reusable immobilized formate dehydrogenases: Promising biocatalysts for in situ regeneration of NADH

  • Barış Binay,
  • Dilek Alagöz,
  • Deniz Yildirim,
  • Ayhan Çelik and
  • S. Seyhan Tükel

Beilstein J. Org. Chem. 2016, 12, 271–277, doi:10.3762/bjoc.12.29

Graphical Abstract
  • methanol or formate from CO2 [10][11]. It was reported that FDH is a promising enzyme for the regeneration of NADH since the reaction product of FDH-catalyzed formate oxidation is CO2 which does not interfere with the purification of the final product [12][13]. However, free FDHs have low thermal stability
  • boidinii as cross-linked enzyme aggregate (CLEA) and demonstrated that the residual activity and thermal stability of CLEA were strictly dependent on the type of cross-linker. Epoxy group containing supports are widely used in enzyme immobilization studies to obtain highly stable enzyme preparations by
  • ethylenediamine and then activated with glutaraldehyde, and Immobead 150 support functionalized with aldehyde groups. The optimum conditions of free and immobilized FDH preparations were determined for formate oxidation. The thermal stability of free and immobilized FDH preparations was tested at 35 and 50 °C
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Published 12 Feb 2016

Interactions of cyclodextrins and their derivatives with toxic organophosphorus compounds

  • Sophie Letort,
  • Sébastien Balieu,
  • William Erb,
  • Géraldine Gouhier and
  • François Estour

Beilstein J. Org. Chem. 2016, 12, 204–228, doi:10.3762/bjoc.12.23

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  • energy barrier for complex dissociation revealed the thermal stability conferred upon guest encapsulation within the CD molecules. NMR experiments allow the enantiomers discrimination in presence of a chiral additive to create visible diastereomeric species. 31P NMR spectroscopy in presence of CDs as
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Published 05 Feb 2016

Thermal and oxidative stability of Atlantic salmon oil (Salmo salar L.) and complexation with β-cyclodextrin

  • Daniel I. Hădărugă,
  • Mustafa Ünlüsayin,
  • Alexandra T. Gruia,
  • Cristina Birău (Mitroi),
  • Gerlinde Rusu and
  • Nicoleta G. Hădărugă

Beilstein J. Org. Chem. 2016, 12, 179–191, doi:10.3762/bjoc.12.20

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  • [13][14]. One of the main disadvantages of PUFAs is their low oxidative and thermal stability. The rate of oxidation of such FAs (especially at higher temperatures) drastically increases with the increasing number of double bonds present, even by few thousand times. For example, the relative oxidation
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Published 02 Feb 2016

Synthesis and photophysical characteristics of polyfluorene polyrotaxanes

  • Aurica Farcas,
  • Giulia Tregnago,
  • Ana-Maria Resmerita,
  • Pierre-Henri Aubert and
  • Franco Cacialli

Beilstein J. Org. Chem. 2015, 11, 2677–2688, doi:10.3762/bjoc.11.288

Graphical Abstract
  • evaluated and compared to those of the non-rotaxane counterpart 3. The influence of TM-βCD or TM-γCD encapsulation on the thermal stability, solubility in common organic solvents, film forming ability was also investigated. Polyrotaxane 3·TM-βCD exhibits a hypsochromic shift, while 3·TM-γCD displays a
  • 3·TM-βCD polyrotaxane. The thermal stability of the copolymers was also investigated by TGA (not shown) and the TGA data revealed that all polymers were stable up to about 300 °C. The absorption spectra of 3·TM-βCD and 3·TM-γCD polyrotaxanes and the unthreaded 3 counterpart at a concentration of 10
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Published 21 Dec 2015

Carbon–carbon bond cleavage for Cu-mediated aromatic trifluoromethylations and pentafluoroethylations

  • Tsuyuka Sugiishi,
  • Hideki Amii,
  • Kohsuke Aikawa and
  • Koichi Mikami

Beilstein J. Org. Chem. 2015, 11, 2661–2670, doi:10.3762/bjoc.11.286

Graphical Abstract
  • reaction temperature from 160 °C to 200 °C accelerated the decarboxylation of CF3CO2K [36] (Scheme 3). The trifluoromethylation using a microreactor resulted in a good yield within a short reaction time by virtue of the thermal stability of CF3Cu and control of mixing. Taking advantage of the flow
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Published 18 Dec 2015

Photoinduced 1,2,3,4-tetrahydropyridine ring conversions

  • Baiba Turovska,
  • Henning Lund,
  • Viesturs Lūsis,
  • Anna Lielpētere,
  • Edvards Liepiņš,
  • Sergejs Beljakovs,
  • Inguna Goba and
  • Jānis Stradiņš

Beilstein J. Org. Chem. 2015, 11, 2166–2170, doi:10.3762/bjoc.11.234

Graphical Abstract
  • attention has been paid to organic aromatic or heterocyclic hydroperoxides, probably due to their low thermal stability and high reactivity. Stable organic hydroperoxides were isolated in the early 1950s as products of autoxidation as well as catalytic oxygenation of indoles and tetrahydrocarbazoles [3][4
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Published 11 Nov 2015

Olefin metathesis in air

  • Lorenzo Piola,
  • Fady Nahra and
  • Steven P. Nolan

Beilstein J. Org. Chem. 2015, 11, 2038–2056, doi:10.3762/bjoc.11.221

Graphical Abstract
  • has exhibited a rapid growth in use in recent years and is quickly becoming a mainstream catalyst in metathesis-type reactions (Figure 11). These complexes have received significant attention due to their high activity in olefin metathesis [72][73][74][75][76][77][78], their thermal stability and
  • increased activity and maintained the same thermal stability. Again, these complexes showed similar activity to the Grubbs 2nd generation catalysts [77][78], and are stable when stored under air. Nolan reported the synthesis of Grubbs’ 2nd generation catalyst (15) from indenylidene complexes 84, by simple
  • 2009, surely inspired by the aforementioned work, the Verpoort group reported a family of indenylidene Schiff base–ruthenium complexes (111a–f, Figure 17) for CM and RCM reactions in air [98]. They combined the higher thermal stability of indenylidene complexes and the tunability and stability of
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Published 30 Oct 2015

Hexacoordinate Ru-based olefin metathesis catalysts with pH-responsive N-heterocyclic carbene (NHC) and N-donor ligands for ROMP reactions in non-aqueous, aqueous and emulsion conditions

  • Shawna L. Balof,
  • K. Owen Nix,
  • Matthew S. Olliff,
  • Sarah E. Roessler,
  • Arpita Saha,
  • Kevin B. Müller,
  • Ulrich Behrens,
  • Edward J. Valente and
  • Hans-Jörg Schanz

Beilstein J. Org. Chem. 2015, 11, 1960–1972, doi:10.3762/bjoc.11.212

Graphical Abstract
  • determined solid contents often times exceeded the theoretical value derived from the amounts of monomer and surfactant added. This indicates that the catalysts have sufficient activity and thermal stability under the chosen conditions to promote complete ROMP of DCPD and the DCPD/COE monomer mixture. After
  • –alkylidene complexes 14 and 15, they should exhibit much lower thermal stability due to high initiation rates [57]. However, the ability to quantitatively convert the monomers indicates that species 14 and 15 either are stabilized in the aqueous solvent, i.e., via H2O donation, or the species rapidly migrate
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Published 21 Oct 2015
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