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991.
992.
Sengupta O Chakrabarty R Mukherjee PS 《Dalton transactions (Cambridge, England : 2003)》2007,(40):4514-4516
A new 3D framework [Mn4(5-pmc)4(1,1-N3)4]n () composed of a rare MnII4 square as the repeating secondary building unit, representing the first coordination polymer of 5-pyrimidinecarboxylate (5-pmc) has been successfully synthesized and characterized by X-ray single crystal structure analysis. 相似文献
993.
The synthetic correlation between two different antibiotic frameworks, the beta-lactams and 2-oxazolidinones, is described for the first time. In this approach, 2-oxazolidinones are prepared in stereomerically pure form from 3-hydroxy beta-lactams by a ring-opening-cyclization isomerization process. Application of this methodology to the total synthesis of the cytokine modulator, (-)-cytoxazone, and its three stereoisomers is demonstrated. [reaction: see text]. 相似文献
994.
A glycine Schiff base Michael addition is used in sequence with free radical-mediated aryl amination to ultimately arrive at the ambiguine G ABC-tricycle convergently. Additionally, thermal Diels-Alder cycloaddition of beta-chloromethacrolein with Cohen's diene is used to diastereoselectively construct the D-cyclohexane ring bearing a neopentyl chloride. 相似文献
995.
Heterobimetallic complexes of the type R2Si(HL)Cl2 and R2SiL2 (where R = Me, Et, Ph; L = ferrocenyl aroylhydrazone) have been synthesized at 40 °C to 50 °C and at room temperature (25
°C), respectively, and characterized by elemental analysis, molar conductance, infrared and NMR (1H, 13C and 29Si) spectral data. The ligands behave as bidentate, coordinating through the azomethine nitrogen and the oxygen in the amidic
and the imidic acid forms of the ligand at low temperature and at room temperature, respectively. The ligands and their organosilicon
complexes have been evaluated for the antifungal activity against Alternaria alternata, Fusarium oxysporum and Rhizoctonia solani, as well as antibacterial activity against gram negative, Escherichia coli and gram positive, Bacillus subtilis, at 28 °C. Organosilicon complexes of ferrocenyl aroylhydrazone were found to be more potent than the parent ligands.
相似文献
996.
In this Letter, we report the confinement of a uniform beam of light (lambda(1) = 400 nm) at the nodes of a standing wave (lambda(2) = 532 nm) via absorbance modulation. In the present implementation of absorbance modulation, a thin polymer film containing a photochromic azobenzene side chain is exposed to a standing wave at lambda(2) and a uniform beam at lambda(1), resulting in alternate regions of high and low absorbance. Light at lambda(1) is localized around the low-absorbance regions. Using photoresist exposures, we mapped out the localized light intensity distribution, which agrees well with our theoretical model. Since the width of this distribution is primarily determined by the ratio of the intensities at the two wavelengths, this technique opens up the possibility of localizing light fields below the diffraction limit using far-field optics. 相似文献
997.
Leys J Wübbenhorst M Preethy Menon C Rajesh R Thoen J Glorieux C Nockemann P Thijs B Binnemans K Longuemart S 《The Journal of chemical physics》2008,128(6):064509
The electrical conductivities of 1-alkyl-3-methylimidazolium tetrafluoroborate ionic liquids and of 1-hexyl-3-methylimidazolium ionic liquids with different anions were determined in the temperature range between 123 and 393 K on the basis of dielectric measurements in the frequency range from 1 to 10(7) Hz. Most of the ionic liquids form a glass and the conductivity values obey the Vogel-Fulcher-Tammann equation. The glass transition temperatures are increasing with increasing length of the alkyl chain. The fragility is weakly dependent on the alkyl chain length but is highly sensitive to the structure of the anion. 相似文献
998.
Andhariya N Chudasama B Patel R Upadhyay RV Mehta RV 《Journal of colloid and interface science》2008,323(1):153-157
In the present investigation we report the effect of capillary diameter and the direction of applied magnetic field on the rotational viscosity of water and kerosene based ferrofluids. We found that changes in the field induced rotational viscosity are larger in the case of water based magnetic fluid than that of kerosene based fluid. The field induced rotational viscosity is found to be inversely proportional to the capillary diameter and it falls exponentially as a function of the angle between the direction of field and vorticity of flow. Magnetophoretic mobility and hydrodynamic volume fraction of nanomagnetic particles are determined for above cases. 相似文献
999.
Uday C. Mashelkar Deepak M. Rane Rajesh S. Kenny 《Journal of heterocyclic chemistry》2008,45(3):865-872
1000.
Pandey RK Wang L Wallock NJ Lindeman S Donaldson WA 《The Journal of organic chemistry》2008,73(18):7236-7245
The reactivity of (2-alkenyl-3-pentene-1,5-diyl)iron complexes toward olefin metathesis, cycloaddition, and mild oxidations (MnO 2 or mCPBA) was examined. Cycloaddition reactions were observed to occur with modest diastereoselectivity (33-63% de). Decomplexation of the (3-pentenediyl) ligand may be accomplished by oxidation with either CAN or alkaline hydrogen peroxide to afford vinylcyclopropanecarboxylates or divinylcyclopropanecarboxylates. Reduction of the latter, followed by Cope rearrangement generates cycloheptadienylmethanols. These studies demonstrate that (2-alkenyl-3-pentene-1,5-diyl)iron complexes can serve as organometallic scaffolds for the preparation of a wide variety of structural motifs containing up to 5 contiguous stereocenters. 相似文献