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261.
Dr. Hashem Amini Dr. Željka Ban Matthias Ferger Sabine Lorenzen Florian Rauch Dr. Alexandra Friedrich Dr. Ivo Crnolatac Prof. Adriana Kenđel Prof. Snežana Miljanić Dr. Ivo Piantanida Prof. Dr. Todd B. Marder 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(27):6017-6028
A bis-triarylborane tetracation (4-Ar2B-3,5-Me2C6H2)-C≡C−C≡C-(3,5-Me2C6H2-4-BAr2 [Ar=(2,6-Me2-4-NMe3-C6H2)+] ( 24+ ) shows distinctly different behaviour in its fluorimetric response than that of our recently published bis-triarylborane 5-(4-Ar2B-3,5-Me2C6H2)-2,2′-(C4H2S)2–5′-(3,5-Me2C6H2-4-BAr2) ( 34+ ). Single-crystal X-ray diffraction data on the neutral bis-triarylborane precursor 2 N confirm its rod-like dumbbell structure, which is shown to be important for DNA/RNA targeting and also for BSA protein binding. Fluorimetric titrations with DNA/RNA/BSA revealed the very strong affinity of 24+ and indicated the importance of the properties of the linker connecting the two triarylboranes. Using the butadiyne rather than a bithiophene linker resulted in an opposite emission effect (quenching vs. enhancement), and 24+ bound to BSA 100 times stronger than 34+ . Moreover, 24+ interacted strongly with ss-RNA, and circular dichroism (CD) results suggest ss-RNA chain-wrapping around the rod-like bis-triarylborane dumbbell structure like a thread around a spindle, a very unusual mode of binding of ss-RNA with small molecules. Furthermore, 24+ yielded strong Raman/SERS signals, allowing DNA or protein detection at ca. 10 nm concentrations. The above observations, combined with low cytotoxicity, efficient human cell uptake and organelle-selective accumulation make such compounds intriguing novel lead structures for bio-oriented, dual fluorescence/Raman-based applications. 相似文献
262.
Florian Rauch Sonja Fuchs Dr. Alexandra Friedrich Dr. Daniel Sieh Dr. Ivo Krummenacher Prof. Dr. Holger Braunschweig Prof. Dr. Maik Finze Prof. Dr. Todd B. Marder 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(56):12794-12808
Three different perfluoroalkylated borafluorenes ( F Bf ) were prepared and their electronic and photophysical properties were investigated. The systems have four trifluoromethyl moieties on the borafluorene moiety as well as two trifluoromethyl groups at the ortho positions of their exo-aryl moieties. They differ with regard to the para substituents on their exo-aryl moieties, being a proton ( F XylFBf , FXyl: 2,6-bis(trifluoromethyl)phenyl), a trifluoromethyl group ( F MesFBf , FMes: 2,4,6-tris(trifluoromethyl)phenyl) or a dimethylamino group ( p -NMe2-FXylFBf , p-NMe2-FXyl: 4-(dimethylamino)-2,6-bis(trifluoromethyl)phenyl), respectively. All derivatives exhibit extraordinarily low reduction potentials, comparable to those of perylenediimides. The most electron-deficient derivative F MesFBf was also chemically reduced and its radical anion isolated and characterized. Furthermore, all compounds exhibit very long fluorescent lifetimes of about 250 ns up to 1.6 μs; however, the underlying mechanisms responsible for this differ. The donor-substituted derivative p -NMe2-FXylFBf exhibits thermally activated delayed fluorescence (TADF) from a charge-transfer (CT) state, whereas the F MesFBf and F XylFBf borafluorenes exhibit only weakly allowed locally excited (LE) transitions due to their symmetry and low transition-dipole moments. 相似文献
263.
We have performed measurements of thermal diffusion coefficients DT and solvent self-diffusion coefficients Dss in semidilute to concentrated polymer solutions. Solutes of different glass transition temperatures and solvents of different solvent qualities have been used. The investigated systems are in detail: poly(dimethyl-siloxane) in toluene, tristyrene in toluene, polystyrene in toluene, polystyrene in tetrahydrofuran, polystyrene in benzene, and polystyrene in cyclohexane. The thermal diffusion data are compared to our data and literature data for solvent self-diffusion coefficients. In all systems the concentration dependence of DT closely parallels the one of Dss which may be viewed as a local probe for friction on a length scale of the size of one polymer segment. This identifies local friction as the dominating parameter determining the concentration dependence of DT. Solvent quality, in contrast, has no influence on DT. 相似文献
264.
Alessandro Ballestrero Benedikt Biedermann Simon Brass Ansgar Denner Stefan Dittmaier Rikkert Frederix Pietro Govoni Michele Grossi Barbara Jäger Alexander Karlberg Ezio Maina Mathieu Pellen Giovanni Pelliccioli Simon Plätzer Michael Rauch Daniela Rebuzzi Jürgen Reuter Vincent Rothe Christopher Schwan Hua-Sheng Shao Pascal Stienemeier Giulia Zanderighi Marco Zaro Dieter Zeppenfeld 《The European Physical Journal C - Particles and Fields》2018,78(8):671
Vector-boson scattering processes are of great importance for the current run-II and future runs of the Large Hadron Collider. The presence of triple and quartic gauge couplings in the process gives access to the gauge sector of the Standard Model (SM) and possible new-physics contributions there. To test any new-physics hypothesis, sound knowledge of the SM contributions is necessary, with a precision which at least matches the experimental uncertainties of existing and forthcoming measurements. In this article we present a detailed study of the vector-boson scattering process with two positively-charged leptons and missing transverse momentum in the final state. In particular, we first carry out a systematic comparison of the various approximations that are usually performed for this kind of process against the complete calculation, at LO and NLO QCD accuracy. Such a study is performed both in the usual fiducial region used by experimental collaborations and in a more inclusive phase space, where the differences among the various approximations lead to more sizeable effects. Afterwards, we turn to predictions matched to parton showers, at LO and NLO: we show that on the one hand, the inclusion of NLO QCD corrections leads to more stable predictions, but on the other hand the details of the matching and of the parton-shower programs cause differences which are considerably larger than those observed at fixed order, even in the experimental fiducial region. We conclude with recommendations for experimental studies of vector-boson scattering processes. 相似文献
265.
C. E. Koning R. Fayt W. Bruls L.v.D. Vondervoort T. Rauch PH. Teyssi 《Macromolecular Symposia》1993,75(1):159-166
The compatibilization and impact modification of blends of a relatively new engineering plastic polyamide 4.6 (PA 4.6) and a poly(aryl ether sulfone) (PSU) are investigated. PSU-b-PA6 block copolymers, which can be easily synthesized by ring opening polymerization of ϵ-caprolactam in the presence of a commercial PSU, were found to be very efficient emulsifiers for these incompatible blends. Small amounts (1–4%) of copolymer are sufficient to significantly reduce the particle size and to improve the tensile and impact properties. Combinations of the copolymer and an impact modifier (ethylene-propylene rubber grafted with maleic anhydride) are synergistic and high impact PSU/PA 4.6 alloys are obtained in that way. 相似文献
266.
CaF2-crystals belong to the standard materials, used in optical precision instruments. As well as the traditional optics for microscopy new developments in the field of DUV-lithography (projecting lenses made out of CaF2 and quartz) need a homogeneity of the refractive index in the order of 10−6, but over much larger volumes (diameter of the projecting lenses for lithography >100mm). Some interesting physical connections between the real structure of the crystals and the homogeneity of refractive index are discussed. 相似文献
267.
The absorption constants of Neodymium in YAG are determined at the absorption lines 434.4 nm; 588.6 nm; 868 nm and compared with literature data. The influence of measuring parameters is discussed. The calibration of the concentration is made absorptionspectrophotometrically by comparison of chemically decomposed solutions of YAG crystals with solutions of mixtures Y2O3/Al2O3/Nd2O3. The measurement of the near-edge absorption is shown to be a practical method for characterization of stoichiometric composition of Nd: YAG crystals. 相似文献