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381.
K.-H. Thiele U. Bhme K. Peters E.-M. Peters L. Walz H. G. Von Schnering 《无机化学与普通化学杂志》1993,619(4):771-774
Synthesis and Molecular Structure of [1,3-(Me3Si)2C5H3](Me3SiC5H4)ZrCl2 . The unsymmetrically substituted zirconocene dichloride was prepared by reaction of trimethylsilylcyclopentadienyl lithium and 1,3-bis(trimethylsilyl)cyclopentadienyl lithium with ZrCl4 · 2 THF. The molecular structure was determined (P21/a; a = 1 357.9, b = 1 900.0, c = 1 043.2 pm, β = 105,16°). The Zr? Cl distance are remarkably short. 相似文献
382.
Zirconium Diazabutadiene Complexes of the Type Zr(DAD)3 1,4-Diazabutadienes (DAD), RN?CPh? CPh?NR 1 (R = C6H5 a , CH3C6H4 b , CH3OC6H4 c ), react with ZrCl4 · 2 THF with formation of complexes of the type ZrCl4 · DAD 2 . At interaction with lithium diazadienides Li2DAD deep coloured complexes of the composition Zr(DAD)3 3 are formed. The new compounds were characterized by elemental analysis, i.r., 1H- and 13C-n.m.r. spectra. 相似文献
383.
Gerhard Thiele Günther Liehr Ekkehard Lindner 《Journal of organometallic chemistry》1974,70(3):427-435
The molecular structure of [(C6H5)3P]2Pd(C3H4) has been determined from three-dimensional X-ray diffraction data. The crystal belongs to the triclinic system, space group P, with two formula units in a cell of dimensions: a = 19.475(2), b = 10.204(2), c = 18.341(2) Å, α = 108.46(2), β = 85.46(1), and γ = 118.80(1)°.One of the olefinic bonds of allene is coordinated to the palladium atom: PdC(1) = 2.118(9) and PdC(2) = 2.067(8) Å. The coordinated allene is no longer linear, the C(1)C(2)C(3) angle being 148.3(8)°. The C(1)C(2) distance is 1.401(11) Å, whereas the uncoordinated bond remains unchanged [C(2)C(3) = 1.304(12) Å]. The Pd, P(1), P(2), C(1) and C(2) atoms lie almost in the same plane. 相似文献
384.
Thomas H Paasch S Machill S Thiele S Herzog K Hemmer M Gasteiger J Salzer R 《Fresenius' Journal of Analytical Chemistry》2001,371(1):4-10
In this report we describe our experience in the analytical chemistry curriculum of teaching spectrometer principles and preparing spectroscopy laboratory exercises by means of virtual instruments. The benefits of the intensified preparation of laboratory exercises by virtual instruments will be evaluated with respect to the subsequent handling of real instruments. The utilization of in-house electronic media with Internet resources for elucidation and verification of a structural assignment will also be considered. 相似文献
385.
Intramolecular C? H Activation at Reaction of Bis(benzylcyclopentadienyl)zirconium Dichloride with Vinyllithium — Formation of a Crotyl Zirconacyclus Bis(benzylcyclopentadienyl)zirconium dichloride, (C6H5CH2? C5H4)2ZrCl2 ( V ), reacts with vinyl lithium with formation of the chiral compound (C6H5CH2? C5H4)? ? CH2CH=CHCH3 ( IX ) as the product of vinyl group coupling and an orthometallation reaction. The reaction mechanism and the 13C n.m.r. spectrum are discussed. 相似文献
386.
Contributions to the Chemistry of Transition Metal Alkyl Compounds. XXXV. Reactions in Tetrabenzyl Titanium/Alkyllithium Systems Organotitanium(IV) complexes of the type Li[(C6H5CH2)4TiR] (R = CH3, C2H5, n-C4H9) were isolated from tetrabenzyl titanium and lithium alkyls at deep temperature. The reddish brown, crystalline compounds decompose between ?30 and 0°C with formation of benzyltitanates(II) which composition differs between Li2[Ti(CH2C6H5)4] and Li[Ti(CH2C6H5)3]. From these complexes pure dibenzyl titanium can be isolated. The reaction mechanism is discussed. Experiments for isolation of a benzyl titanium(III) compound from (C6H5CH2)4Ti/RLi systems failed in all cases. Recent informations about stable tribenzyl titanium obtained from tetrabenzyl titanium and ethyl lithium could not be confirmed. 相似文献
387.
Kevin Knoll Dominik Herold Max Hirschmann Christina M. Thiele 《Magnetic resonance in chemistry : MRC》2022,60(6):563-571
A supramolecular, lyotropic liquid crystalline alignment medium based on an azobenzene-containing 1,3,5-benzenetricarboxamide (BTA) building block is described and investigated. As we demonstrate, this water-based system is suitable for the investigation of various water-soluble analytes and allows for a scaling of alignment strength through variation of temperature. Additionally, alignment is shown to reversibly collapse above a certain temperature, yielding an isotropic solution. This collapse allows for isotropic reference measurements, which are typically needed in addition to those in an anisotropic environment, to be performed using the same sample just by varying the temperature. The medium described thus provides easy access to anisotropic NMR observables and simplifies structure elucidation techniques based thereon. 相似文献
388.
Owing to the recent developments concerning residual dipolar couplings (RDCs), the interest in methods for the accurate determination of coupling constants is renascenting. We intended to use the J-modulated ADEQUATE experiment by K?vér et al. for the measurement of (13)C - (13)C coupling constants at natural abundance. The use of adiabatic composite chirp pulses instead of the conventional 180 degrees pulses, which compensate for the offset dependence of (13)C 180 degrees pulses, led to irregularities of the line shapes in the indirect dimension causing deviations of the extracted coupling constants. This behaviour was attributed to coupling evolution, during the time of the adiabatic pulse (2 ms), in the J-modulation spin echo. The replacement of this pulse by different kinds of refocusing pulses indicated that a pair of BIPs (broadband inversion pulses), which behave only partially adiabatic, leads to correct line shapes and coupling constants conserving the good sensitivity obtained with adiabatic pulses. 相似文献
389.
Babay PA Gettar RT Magallanes JF Becquart ET Thiele B Batistoni DA 《Journal of chromatography. A》2007,1157(1-2):227-236
Normal-phase separation of technical grade nonylphenol (t-NP, about 90% 4-nonylphenol), 4-nonylphenol mono-ethoxylate (4-NP1EO) and 4-nonylphenol di-ethoxylate (4-NP2EO) was assessed, with the inclusion of column temperature as an active variable. The compound 2,4,6-trimethylphenol was evaluated for use as internal standard. Isocratic elution with 2-propanol/hexanes mixtures from an amino-silica column and spectrometric UV detection at 277 nm were employed. Technical nonylphenol presented a significant contribution from unknown substances that eluted with retention times similar to that of 4-NP1EO. GC-MS analysis of the unknowns allowed to identify them as isomers of 2-NP. The response of the system to joint variations in flow rate, eluent composition and column temperature was investigated by means of Doehlert statistical experimental design. A model for retention of the analytes as a function of the experimental variables was proposed, and separation selectivity was studied. Selection of the optimal working zone was made through desirability function (D) calculations. Potential co-elution of 2-NP isomers with 4-NP1EO was considered when optimizing the separation. The occurrence of a restricted region of the experimental space where baseline resolution of analytes, associated impurities and internal standard results feasible (D not equal to 0) is apparent. 相似文献
390.
Glenzer SH Landen OL Neumayer P Lee RW Widmann K Pollaine SW Wallace RJ Gregori G Höll A Bornath T Thiele R Schwarz V Kraeft WD Redmer R 《Physical review letters》2007,98(6):065002
We present the first collective x-ray scattering measurements of plasmons in solid-density plasmas. The forward scattering spectra of a laser-produced narrow-band x-ray line from isochorically heated beryllium show that the plasmon frequency is a sensitive measure of the electron density. Dynamic structure calculations that include collisions and detailed balance match the measured plasmon spectrum indicating that this technique will enable new applications to determine the equation of state and compressibility of dense matter. 相似文献