Unusual behavior in the reactivity of 5-substituted-1H-tetrazoles in a resistively heated microreactor

• Bernhard Gutmann,
• Toma N. Glasnov,
• Tahseen Razzaq,
• Walter Goessler,
• Dominique M. Roberge and
• C. Oliver Kappe

Beilstein J. Org. Chem. 2011, 7, 503–517, doi:10.3762/bjoc.7.59

• 1,5-diphenyltetrazole by about 60 °C [39]. However, in case of the parent tetrazole (CN4H2) itself, differential scanning calorimetry (DSC) experiments suggest that the decomposition onset temperature does not change significantly when the material is contaminated with either Fe or 316 stainless steel

Amphiphilic dendritic peptides: Synthesis and behavior as an organogelator and liquid crystal

• Baoxiang Gao,
• Hongxia Li,
• Defang Xia,
• Sufang Sun and
• Xinwu Ba

Beilstein J. Org. Chem. 2011, 7, 198–203, doi:10.3762/bjoc.7.26

• dendritic polyaspartic acid were designed and synthesized. The organogel and liquid crystal properties of these amphiphilic dendritic peptides were fully studied by field-emission SEM, temperature dependent FT-IR, differential scanning calorimetry, polarization optical microscopy and X-ray diffraction

• crystalline behavior Thermotropic behavior of ADPs was investigated by a combination of differential scanning calorimetry (DSC), polarization optical microscopy (POM) and X-ray diffraction (XRD) experiments. Figure 4 shows DSC curves of amphiphilic dendritic peptides. In the DSC scan from −60 °C to 200 °C, G1

• CDCl3 with tetramethylsilane as internal standard unless indicated otherwise. Mass spectra were carried out using MALDI-TOF/TOF matrix assisted laser desorption ionization mass spectrometry with Autoflex III Smartbeam (Bruker Daltonics Inc). Differential scanning calorimetry (DSC) was carried out with a

About the activity and selectivity of less well-known metathesis catalysts during ADMET polymerizations

• Hatice Mutlu,
• Lucas Montero de Espinosa,
• Oĝuz Türünç and
• Michael A. R. Meier

Beilstein J. Org. Chem. 2010, 6, 1149–1158, doi:10.3762/bjoc.6.131

• , the physical properties of the polymers are correspondingly affected. A different insight into the effect of the isomerization ratio on the thermal properties of the polymers can be achieved by differential scanning calorimetry (DSC) analysis of the synthesized polymers. The thermal behavior of two

• performed relative to PMMA standards (Polymer Standards Service, Mp 1100–981.000 Da). Differential scanning calorimetry (DSC) experiments were carried out under a nitrogen atmosphere at a heating rate of 10 °C × min−1 with a DSC821e (Mettler Toledo) calorimeter up to a temperature of 150 °C with a sample

Formation of epoxide-amine oligo-adducts as OH-functionalized initiators for the ring-opening polymerization of ε-caprolactone

• Julia Theis and
• Helmut Ritter

Beilstein J. Org. Chem. 2010, 6, 938–944, doi:10.3762/bjoc.6.105

• . Elemental analysis (EA) was carried out with a Perkin-Elmer Analyzer 2400 with an accuracy of measurement of ±0.3%. Differential scanning calorimetry (DSC) measurements were performed using a Mettler Toledo DSC 822 controller apparatus equipped with a sample robot TSO801RO. The apparatus was controlled over

• oligomers with repetitive units. Molecular weights calculated from the GPC curve are about 1700 g mol−1 for Mn and 2600 g mol−1 for Mw. The molecular weight distribution of the addition polymer 4 is relatively narrow (Mw/Mn = 1.6) which is typical for low molecular weight polymers. The differential scanning

• calorimetry (DSC) curve of compound 4 shows a glass transition temperature (Tg) at 63 °C. The low molecular weight epoxide-amine adduct 4 is soluble, e.g., in tetrahydrofuran (THF), methanol, chloroform but insoluble in n-hexane and water. We also carried out the above described one-pot reaction in THF as

Chiral gels derived from secondary ammonium salts of (1R,3S)-(+)-camphoric acid

• Tapas Kumar Adalder,
• N. N. Adarsh,
• Ravish Sankolli and
• Parthasarathi Dastidar

Beilstein J. Org. Chem. 2010, 6, 848–858, doi:10.3762/bjoc.6.100

• )-(+)-camphoric acid and various secondary amines were prepared based on supramolecular synthon rationale. Out of seven salts prepared, two showed moderate gelation abilities. The gels were characterized by differential scanning calorimetry, table top rheology, scanning electron microscopy, single crystal and

• table top rheology, differential scanning calorimetry (DSC), scanning electron microscopy (SEM), single- and powder X-ray diffraction (SXRD and PXRD, respectively). Single crystal structures of two gelators and one nongelator, i.e., DBUAMC 3, DBAMC 6, and DCHADC 1, respectively were determined and

• out with a JEOL, JMS-6700F, Field Emission Scanning Electro Microscope. Differential Scanning Calorimetry (DSC) was recorded with a Perkin-Elmer, Diamond DSC. Powder X-ray patterns were recorded on a Bruker AXS D8 Advance Powder (Cu Kα1 radiation, λ = 1.5406 Å) diffractometer. General Synthetic

Hybrid biofunctional nanostructures as stimuli-responsive catalytic systems

• Gernot U. Marten,
• Thorsten Gelbrich and
• Annette M. Schmidt

Beilstein J. Org. Chem. 2010, 6, 922–931, doi:10.3762/bjoc.6.98

• to the oscillating magnetic field. Via a fiber-optical sensor the fluid temperature T was measured against time t. For UV–vis spectroscopy, a Nicolet UV 540 spectroscope, a Unicam UV 500 or a Perkin Elmer Lambda19 with a thermostat Colora NBDS was used. Differential scanning calorimetry thermograms

Novel multi-responsive P2VP-block-PNIPAAm block copolymers via nitroxide-mediated radical polymerization

• Cathrin Corten,
• Katja Kretschmer and
• Dirk Kuckling

Beilstein J. Org. Chem. 2010, 6, 756–765, doi:10.3762/bjoc.6.89

• nitroxide terminated polymers were characterized by nuclear magnetic resonance (NMR) spectroscopy, size exclusion chromatography (SEC) and matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS). Thermal properties were investigated by the differential scanning

• calorimetry (DSC). Block copolymers showed pH- and temperature-responsive solubility in aqueous media. By increasing the P2VP content, the phase transition temperature shifted to lower temperatures (e.g. 26 °C for P2VP114-block-PNIPAAm180). Depending on the resulting block length, temperature and pH value of

Chromo- and fluorophoric water-soluble polymers and silica particles by nucleophilic substitution reaction of poly(vinyl amine)

• Katja Hofmann,
• Ingolf Kahle,
• Frank Simon and
• Stefan Spange

Beilstein J. Org. Chem. 2010, 6, No. 79, doi:10.3762/bjoc.6.79

• -O-β-dimethylcyclodextrin was kindly supplied by Wacker Chemie. The authors thank Dr. A. Seifert and R. Jaeschke for 13C-{1H}-CP-MAS NMR measurements and the determination of the glass-transition temperatures by means of differential scanning calorimetry (DSC).

Poly(glycolide) multi-arm star polymers: Improved solubility via limited arm length

• Florian K. Wolf,
• Anna M. Fischer and
• Holger Frey

Beilstein J. Org. Chem. 2010, 6, No. 67, doi:10.3762/bjoc.6.67

• series was used as an integrated instrument, including a PSS Gral column (104/104/102 Å porosity) and RI detector. Calibration was achieved with poly(ethylene glycol) standards provided by Polymer Standards Service (PSS)/Germany. Differential scanning calorimetry (DSC) measurements were carried out on a

Free radical homopolymerization of a vinylferrocene/cyclodextrin complex in water

• Helmut Ritter,
• Beate E. Mondrzik,
• Matthias Rehahn and
• Markus Gallei

Beilstein J. Org. Chem. 2010, 6, No. 60, doi:10.3762/bjoc.6.60

• experiment was performed at least five times to obtain statistical information. Differential scanning calorimetry (DSC) measurements were performed on a Mettler DSC-30 instrument in a temperature range of −25 to 200 °C at a heating rate of 15 °C × min−1 as the average of five measurements using the midpoint

• added to the mixture followed by the addition of a similar amount of the initiator after 8 h. After a reaction time of 48 h, the reaction mixture was freeze-dried. No residual monomer was evident by thin layer chromatography. According to differential scanning calorimetry (DSC), the obtained

• scanning calorimetry (DSC), and lower critical solution temperature (LCST) measurements. Keywords: cyclodextrin; free radical polymerization; polyvinylferrocene; vinylferrocene; Introduction Since its discovery in 1951, ferrocene [1] and its derivatives and their applications have been the subject of

Synthesis, characterization and photoinduced curing of polysulfones with (meth)acrylate functionalities

• Cemil Dizman,
• Sahin Ates,
• Lokman Torun and
• Yusuf Yagci

Beilstein J. Org. Chem. 2010, 6, No. 56, doi:10.3762/bjoc.6.56

• Spectrum One B spectrometer with a Universal ATR accessory equipped with a single reflection diamond crystal. Solid oligomers were placed over the ATR crystal and maximum pressure was applied using the slip-clutch mechanism. Differential scanning calorimetry (DSC) was performed on a Perkin-Elmer Diamond

• instrument. Photocalorimetry (Photo-DSC) The photo-differential scanning calorimetry (Photo-DSC) measurements were carried out by means of a modified Perkin-Elmer Diamond DSC equipped with a high pressure mercury arc lamp (320–500 nm). A uniform UV light intensity was delivered across the DSC cell to the

Ring-alkyl connecting group effect on mesogenic properties of p-carborane derivatives and their hydrocarbon analogues

• Aleksandra Jankowiak,
• Piotr Kaszynski,
• William R. Tilford,
• Kiminori Ohta,
• Adam Januszko,
• Takashi Nagamine and
• Yasuyuki Endo

Beilstein J. Org. Chem. 2009, 5, No. 83, doi:10.3762/bjoc.5.83

• -benzyloxyphenol with butyryl chloride followed by removal of the protective benzyl group under reductive conditions as described in the literature [36] (Scheme 3). Mesogenic properties Transition temperatures and enthalpies of the newly prepared compounds were determined by differential scanning calorimetry (DSC

Low temperature enantiotropic nematic phases from V-shaped, shape-persistent molecules

• Matthias Lehmann and
• Jens Seltmann

Beilstein J. Org. Chem. 2009, 5, No. 73, doi:10.3762/bjoc.5.73

• purified and characterised by 1H, 13C NMR, mass spectrometry and elemental analysis (see experimental section). Thermotropic Properties The thermotropic behaviour of all materials was investigated by differential scanning calorimetry (DSC) and polarised optical microscopy (POM). The results are collected

Molecular length distribution and the formation of smectic phases

• Nadia Kapernaum,
• C. Scott Hartley,
• Jeffrey C. Roberts,
• Robert P. Lemieux and
• Frank Giesselmann

Beilstein J. Org. Chem. 2009, 5, No. 65, doi:10.3762/bjoc.5.65

• opposite signs of E. A Netzsch DSC-204 Phoenix instrument was used for differential scanning calorimetry analyses at a scan rate of 5 K min−1. Structure of different liquid crystalline phases build with two kinds of hard spherocylinders with strongly differing lengths. Molecular structure of the mesogens

Influence of spacer chain lengths and polar terminal groups on the mesomorphic properties of tethered 5-phenylpyrimidines

• Gundula F. Starkulla,
• Elisabeth Kapatsina,
• Angelika Baro,
• Frank Giesselmann,
• Stefan Tussetschläger,
• Martin Kaller and
• Sabine Laschat

Beilstein J. Org. Chem. 2009, 5, No. 63, doi:10.3762/bjoc.5.63

• nucleophilic substitution. The mesomorphic behaviour of these compounds was investigated by differential scanning calorimetry (DSC), polarizing optical microscopy (POM) and X-ray diffraction (WAXS and SAXS) and revealed smectic A mesophases for bromides, chlorides and azides 3, 4 and 6. For these compounds a

• the monochromator. The diffraction patterns were recorded on a real-time 2D-detector (HI-STAR, Bruker). The calibration of the patterns occurred with the powder pattern of Ag-Behenate. Differential scanning calorimetry (DSC) was performed using a Mettler Toledo DSC822, and polarizing optical

• deprotonation of hydroxy derivative 8 with NaH in DMF for 40 min at 0 °C followed by addition of 1-bromo-3-propionitrile at room temperature. After 12 h, the cyanide 7b was obtained in 33% yield. Mesomorphic properties: Mesomorphic properties of compounds 3–10 were investigated by differential scanning

1-(4-Alkyloxybenzyl)-3-methyl-1H-imidazol-3-ium organic backbone: A versatile smectogenic moiety

• William Dobbs,
• Laurent Douce and
• Benoît Heinrich

Beilstein J. Org. Chem. 2009, 5, No. 62, doi:10.3762/bjoc.5.62

• temperature). The mesomorphic properties were studied by polarizing optical microscopy, differential scanning calorimetry and X-ray diffraction. With the support of dilatometry, models for the lamellar supramolecular arrangement of the salts are proposed and its evolution is discussed as a function of the

• ][25][26][27][28][29][30]. Their characterization was the result of the combination and interpretation of thermal studies (Thermogravimetry Analysis or TGA, Differential Scanning Calorimetry or DSC), direct polarized optical microscopy (POM) observation and small angle X-ray diffraction studies (SAXS

Coaxial electrospinning of liquid crystal-containing poly(vinylpyrrolidone) microfibres

• Eva Enz,
• Ute Baumeister and
• Jan Lagerwall

Beilstein J. Org. Chem. 2009, 5, No. 58, doi:10.3762/bjoc.5.58

• through a polarising optical microscope (POM) and follow the phase sequence (Figure 2). The fibres are thermally stable enough to allow repeated heating into the isotropic phase of the contained liquid crystal and cooling to room temperature again without any change in appearance. In differential scanning

• calorimetry (DSC) investigations only the transitions of the liquid crystal are found up to about 100 °C, where decomposition of the PVP sheath starts to take place. When fully dried the fibres also show good mechanical stability so that they can be pulled from the glass slide and folded or rolled together

Saddle-shaped tetraphenylenes with peripheral gallic esters displaying columnar mesophases

• Eugen Wuckert,
• Constanze Hägele,
• Frank Giesselmann,
• Angelika Baro and
• Sabine Laschat

Beilstein J. Org. Chem. 2009, 5, No. 57, doi:10.3762/bjoc.5.57

• purification the desired gallic ester-substituted tetraphenylenes 2a–l in 19–72%. In some cases purification turned out to be rather tedious resulting in decreased yields. Mesomorphic properties of compounds 2 were studied by differential scanning calorimetry (DSC), polarizing optical microscopy (POM) and X

• patterns recorded with an imaging plate detector (Fuji BAS SR). In the flat-film camera, the sample was placed in a small hole of a brass block, the temperature of which was controlled by a Lakeshore controller and kept in a 1.5 T magnetic field for alignment. Differential scanning calorimetry (DSC) was

Novel banana-discotic hybrid architectures

• Hari Krishna Bisoyi,
• H. T. Srinivasa and
• Sandeep Kumar

Beilstein J. Org. Chem. 2009, 5, No. 52, doi:10.3762/bjoc.5.52

• discotic dimers. The chemical structures have been characterized by spectral techniques and elemental analysis. The thermal behaviors of the compounds have been investigated by polarizing optical microscopy and differential scanning calorimetry. None of these synthesized compounds exhibit any liquid

• behavior of the novel compounds have been observed by polarizing optical microscopy and differential scanning calorimetry. All the solvent crystallized compounds pass from crystalline state to isotropic liquid state on heating, and on cooling they crystallize into the solid state without any intervening

• differential scanning calorimetry measurements. The absence of either B-phase or discotic columnar mesophase in compound 6 may be explained as follows: since the five-ring banana unit, which otherwise exhibits mesophase with two terminal alkyl chains, is now attached with two bulky triphenylene units at the

A convenient method for preparing rigid-core ionic liquid crystals

• Julien Fouchet,
• Laurent Douce,
• Benoît Heinrich,
• Richard Welter and
• Alain Louati

Beilstein J. Org. Chem. 2009, 5, No. 51, doi:10.3762/bjoc.5.51

• , differential scanning calorimetry and X-ray diffraction. In addition its lamellar crystal structure, electrochemical behaviour and UV (absorption and emission) properties are reported. Keywords: imidazolium; ionic liquid crystals; Ullman reaction; Introduction Over the past decade extensive studies of ionic

• general stability order to be I−< BF4− ≈ PF6−< CF3SO3−< (CF3SO2)2N− (Figure 4). For all the compounds, the mesomorphic behaviour and phase transition temperatures were investigated by polarized optical microscopy (POM), differential scanning calorimetry (DSC), and powder X-ray diffractometry (XRD). To

• were studied with a Leitz polarizing microscope equipped with a Mettler FP80 hot stage and an FP80 central processor. The TGA measurements were carried out on a SDTQ 600 apparatus at scanning rate of 10 °C·min−1. The transition temperatures and enthalpies were measured by differential scanning

Synthesis of mesogenic phthalocyanine-C₆₀ donor–acceptor dyads designed for molecular heterojunction photovoltaic devices

• Yves Henri Geerts,
• Olivier Debever,
• Claire Amato and
• Sergey Sergeyev

Beilstein J. Org. Chem. 2009, 5, No. 49, doi:10.3762/bjoc.5.49

• ) mesophases. Upon heating, transitions to isotropic liquid were observed at 120 °C and 90 °C for 2c and 2d, respectively. For 2c this transition was only detectable by POM and not by differential scanning calorimetry (DSC), while for 2d DSC on heating revealed an endothermic peak at 90 °C [enthalpy 2.7 kJ/mol

Pd/C- Mediated synthesis of indoles in water

• Mohosin Layek,
• Udaya Lakshmi,
• Dipak Kalita,
• Deepak K. Barange,
• Aminul Islam,
• K. Mukkanti and
• Manojit Pal

Beilstein J. Org. Chem. 2009, 5, No. 46, doi:10.3762/bjoc.5.46

• ) are given in hertz. Infrared spectra were recorded on a FTIR spectrometer. Melting points were determined by using thermal analysis and differential scanning calorimetry (DSC) was generated with the help of DSC-60A dector. MS spectra were obtained on a mass spectrometer. Chromatographic (HPLC) purity