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排序方式: 共有301条查询结果,搜索用时 31 毫秒
91.
Dr. Uttam Chakraborty Dr. Serhiy Demeshko Prof. Dr. Franc Meyer M. Sc. Christophe Rebreyend Prof. Dr. Bas de Bruin Prof. Dr. Mihail Atanasov Prof. Dr. Frank Neese Dr. Bernd Mühldorf Prof. Dr. Robert Wolf 《Angewandte Chemie (International ed. in English)》2017,56(27):7995-7999
The 15 valence-electron iron(I) complex [CpArFe(IiPr2Me2)] ( 1 , CpAr=C5(C6H4-4-Et)5; IiPr2Me2=1,3-diisopropyl-4,5-dimethylimidazolin-2-ylidene) was synthesized in high yield from the FeII precursor [CpArFe(μ-Br)]2. 57Fe Mössbauer and EPR spectroscopic data, magnetic measurements, and ab initio ligand-field calculations indicate an S= 3/2 ground state with a large negative zero-field splitting. As a consequence, 1 features magnetic anisotropy with an effective spin-reversal barrier of Ueff=64 cm−1. Moreover, 1 catalyzes the dehydrogenation of N,N-dimethylamine–borane, affording tetramethyl-1,3-diaza-2,4-diboretane under mild conditions. 相似文献
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93.
Arcady Zhukov Mihail Ipatov Ahmed Talaat Margarita Churyukanova Sergei Kaloshkin Valentina Zhukova 《Applied Physics A: Materials Science & Processing》2014,115(2):547-553
We present the results on Giant magneto-impedance effect (GMI) in amorphous and nanocrystalline microwires at frequencies until 4 GHz, paying special attention to tailoring the frequency and magnetic field dependence of the GMI effect. Correlation between magnetoelastic anisotropy and magnetic field dependences of diagonal and off-diagonal impedance components are observed. 相似文献
94.
Dr. Yves‐Marie Legrand Dan Dumitrescu Dr. Arnaud Gilles Eddy Petit Dr. Arie van der Lee Dr. Mihail Barboiu 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(15):4938-4941
Following earlier reports on the photochemical synthesis of 1,3‐dimethylcyclobutadiene 8 , 10 in a protective host matrix, theoretical calculations for the formation of that adduct have been recently performed by Rzepa. 13 The author formulated criticisms based mainly on density functional theory calculations of 1H NMR spectra. According to Rzepa the calculated spectra do not correspond with our measured spectra, which leads him to the conclusion that our interpretation is wrong, and that mainly cyclobutadiene has not been stabilized or even synthesized; we believe, however, that the initial model that Rzepa used for his calculations does not correspond to chemical reality or is at the very least a crude simplification of it, which implies that his calculations cannot match, in every point, our experimental spectra. Rzepa′s simplified models might be ‘reasonable’ from the theoretical point of view; however, in the case of assessment in the solid state, the theoretical setup does not force the system to preserve the confined stabilizing space defined by the crystalline matrix for encapsulated hosts in the solid state. Inversely, in the case of solution modeling, the theoretical setup is too rigid to properly assess the complex equilibria occurring in solution and to accurately determine the NMR spectra of exchanging species in solution. The inconsistency between our experimental results and the results of the theoretical models proposed by Rzepa is such that his conclusions are considered to be too far from experimental reality. Accurate modeling taking in account “reasonable” experimental details would be a worthwhile endeavor. 相似文献
95.
Marin Cernea Mihail Secu Corina Elisabeta Secu Mihaela Baibarac Bogdan S. Vasile 《Journal of nanoparticle research》2011,13(1):77-85
In this study, we report on the nanocrystalline powders of TiO2 and Fe-doped TiO2 (anatase and rutile phases) prepared by sol–gel method. The X-ray diffraction and Raman spectroscopy measurements indicated
the presence of anatase or rutile phase in nanopowders. TEM micrographs showed 10 and 112 nm average particle sizes for anatase
and rutile, respectively. Furthermore, their thermoluminescence properties were analyzed. 相似文献
96.
Dr. Luminita Marin Dr. Simona Moraru Dr. Maria‐Cristina Popescu Alina Nicolescu Cristina Zgardan Prof. Dr. Bogdan C. Simionescu Dr. Mihail Barboiu 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(16):4814-4821
An investigation of the constitutional adaptive gelation process of chitosan/cinnamaldehyde ( C / Cy ) dynagels is reported. These gels generate timely variant macroscopic organization across extended scales. In the first stage, imine‐bond formation takes place “in‐water” and generates low‐ordered hydrogels. The progressive formation of imine bonds further induces “ out‐of‐water” increased reactivity within interdigitated hydrophobic self‐assembled layers of Cy , with a protecting environmental effect against hydrolysis and that leads to the stabilization of the imine bonds. The hydrophobic swelling due to Cy layers at the interfaces reaches a critical step when lamellar self‐organized hybrids are generated (24 hours). This induces an important restructuration of the hydrogels on the micrometric scale, thus resulting in the formation of highly ordered microporous xerogel morphologies of high potential interest for chemical separations, drug delivery, and sensors. 相似文献
97.
Hodisan Teodor Casoni Dorina Beldean-Galea Mihail Simion Cimpoiu Claudia 《平面色谱法杂志一现代薄层色谱法》2008,21(3):213-215
JPC – Journal of Planar Chromatography – Modern TLC - 相似文献
98.
Elmahdy MM Dou X Mondeshki M Floudas G Butt HJ Spiess HW Müllen K 《Journal of the American Chemical Society》2008,130(15):5311-5319
The self-assembly, the molecular dynamics, and the kinetics of structure formation are studied in dipole-functionalized hexabenzocoronene (HBC) derivatives. Dipole substitution destabilizes the columnar crystalline phase except for the dimethoxy- and monoethynyl-substituted HBCs that undergo a reversible transformation to the crystalline phase. The disk dynamics are studied by dielectric spectroscopy and site-specific NMR techniques that provide both the time-scale and geometry of motion. Application of pressure results in the thermodynamic phase diagram that shows increasing stability of the crystalline phase at elevated pressures. Long-lived metastability was found during the transformation between the two phases. These results suggest new thermodynamic and kinetic pathways that favor the phase with the highest charge carrier mobility. 相似文献
99.
100.