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91.
Weigelt S Schnadt J Tuxen AK Masini F Bombis C Busse C Isvoranu C Ataman E Laegsgaard E Besenbacher F Linderoth TR 《Journal of the American Chemical Society》2008,130(16):5388-5389
The adsorption of octylamine on Au(111) under ultrahigh vacuum conditions is investigated. The molecules surprisingly undergo a thermally activated chemical reaction, resulting in formation of trioctylamine as confirmed both by X-ray photoelectron spectroscopy (XPS) and by comparison to the scanning tunneling microscopy (STM) signature of trioctylamine deposited directly onto the surface. 相似文献
92.
Inside Back Cover: Self‐Assembly of Measles Virus Nucleocapsid‐like Particles: Kinetics and RNA Sequence Dependence (Angew. Chem. Int. Ed. 32/2016)
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93.
A densitometric high performance thin-layer chromatographic (HPTLC) method was developed and validated for quantitative analysis of L-DOPA in tablets. Chromatographic separation was achieved on precoated silica gel F 254 HPTLC plates using a mixture of acetone-chloroform-n-butanol-acetic acid glacial-water (60:40:40:40:35 v/v/v/v/v) as mobile phase. Quantitative analysis was carried out at a wavelength of 497 nm. The method was linear between 100 and 500 ng/microL, with a correlation coefficient of 0.999. The intra-assay variation was between 0.26 and 0.65% and the interassay was between 0.52 and 2.04%. The detection limit was 1.12 ng/microL, and the quantification limit was 3.29 ng/microL. The accuracy ranged from 100.40 to 101.09%, with a CV not higher than 1.40%. The method was successfully applied to quantify L-DOPA in real pharmaceutical samples, including the comparison with HPLC measurements. The method was fast, specific, with a good precision, and accurate for the quantitative determination of L-DOPA in tablets. 相似文献
94.
Tyrra W Naumann D Buslei S Kremer S Pantenburg I Scherer H 《Dalton transactions (Cambridge, England : 2003)》2007,(18):1829-1837
[NMe(4)][R(f)Te(SC(S)NR(2))(2)] derivatives are selectively formed by the oxidation of [NMe(4)]TeR(f) (R(f) = CF(3), C(2)F(5)) with [R(2)NC(S)S](2) (NR(2) = NEt(2), NBz(2), N(CH(2))(4)) in almost quantitative yields. An alternative route to obtain the dithiocarbamato complex anions offer reactions of Te[SC(S)NR(2)](2) (NR(2) = NEt(2), NBz(2)) with equimolar amounts of Me(3)SiR(f) and [NMe(4)]F. Some of the derivatives were recrystallized with bulky cations in order to determine the crystal structures. Structural elucidation by diffraction methods exhibit the structural feature of a distorted pentagonal planar environment (resembling "butterflies") around the tellurium centres. The carbamato tellurates can be transferred easily into the neutral derivatives, R(f)TeSC(S)NR(2), upon treatment with Ag[BF(4)]. In solution they equilibrate with Te(2)(R(f))(2) and [R(2)NC(S)S](2) and finally are transformed into Te(R(f))(2), Te[SC(S)NR(2)](2), and Te[SC(S)NR(2)](4), respectively. All compounds are fully characterized by NMR spectroscopic methods ((1)H, (13)C, (19)F, (125)Te). Additionally, synthesis and characterization of the hitherto unknown derivative [NMe(4)]TeC(2)F(5) are described. 相似文献
95.
Rajadurai C Enkelmann V Zoppellaro G Baumgarten M 《The journal of physical chemistry. B》2007,111(17):4327-4334
Two paramagnetic building blocks, 2-(4-ethynyl-1-phenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl (3) and 2-(5-ethynyl-2-pyridyl)-4,4,5,5-tetramethylimidazoline-1-oxyl (4) were synthesized and crystallized. Single crystal X-ray studies of 3 and 4 show the formation of supramolecular head-to-tail one-dimensional H-bonded (N-O...H-C[triple bond]C- type) chain structures with O...C distances of 3.181 and 3.155 A, respectively. High-resolution isotropic liquid state (c相似文献
96.
Hans R. Kricheldorf Sigrid Bhme Gert Schwarz C.‐L. Schultz 《Macromolecular rapid communications》2002,23(14):803-808
The hydrolytic polycondensation of bisphenol‐A bischloroformate in NaOH/CH2Cl2 was studied using triethylamine as the catalyst. Reaction conditions were optimized towards high molar masses. The isolated polycarbonates were characterized by means of SEC and MALDI‐TOF mass spectrometry. The fraction of cyclic polycarbonates strongly increased with higher molecular weights and in the best sample only cycles were detectable (up to 50 000 Da). The largest cycles can compete with cyclic DNS of microorganisms. 相似文献
97.
Lei Zhang Zhi‐Liang Liu Lin‐Hong Weng Dai‐Zheng Liao Zong‐Hui Jiang Shi‐Ping Yan Pan‐Wen Shen Martin Baumgarten 《Helvetica chimica acta》2001,84(4):834-841
The structure of a novel oxido‐aminoxyl (=`nitronyl nitroxide') biradical, 2,2′‐(1‐oxidopyridine‐2,6‐diyl)bis[4,5‐dihydro‐4,4,5,5‐tetramethyl‐3‐oxido‐1H‐imidazol‐1‐oxyl] hydrate ( 1 ⋅H2O) was established by X‐ray analysis in the solid state: monoclinic, space group P21/c, Z=4 with a=12.621(4), b=15.704(5), and c=13.001(4) Å, and β=115.202(6)°. Variable‐temperature magnetic susceptibilities show a weak antiferromagnetic interaction between the two oxido‐substituted aminoxyl moieties of 1 , indicative of a singlet ground state. AM1 Calculations located minima for the possible structure based on the X‐ray crystal structure. A hybride density‐functional‐theory calculation with the UB3LYP method from the X‐ray crystal structure establishes the same spin sign in the two aminoxyl moieties and shows that a small spin density is localized at the C‐atoms of the pyridine moiety. These theoretic results are in good agreement with the determined weak antiferromagnetic interaction of 1 . 相似文献
98.
99.
Stefan Schmitt Martin Baumgarten Joachim Simon Klaus Hafner 《Angewandte Chemie (International ed. in English)》1998,37(8):1077-1081
Simply mixing solutions of the title compound 1 and tetrathiafulvene (TTF) in acetonitrile provides the charge-transfer complex 2 . Here, 1 functions as a novel electron acceptor and is present in the complex as a radical anion. An electrical conductivity of up to 3 S cm−1 was determined for 2 with a two-point powder measurement. 相似文献
100.
For a physical system described by a motion in an energy landscape under holonomic constraints, we study the Γ-convergence
of variational integrators to the corresponding continuum action functional and the convergence properties of solutions of
the discrete Euler–Lagrange equations to stationary points of the continuum problem. This extends the results in Müller and
Ortiz (J. Nonlinear Sci. 14:279–296, 2004) to constrained systems. The convergence result is illustrated with examples of mass point systems and flexible multibody
dynamics.
相似文献