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991.
Homoleptic Zinc Amides: Transition to Monomeric Molecules Zinc chloride reacts with the lithium salts of the bulky secondary amines HN(i-Bu)2 and HN(t-Bu)2 to form the corresponding homoleptic zinc compounds {Zn[N(i-Bu)2]2}2 ( 1 ) and Zn[N(t-Bu)2]2 ( 2 ). The NMR spectroscopic and mass spectrometric results as well as the molecular weight determinations and X-ray diffraction data are consistent with a dimeric structure of 1 and a monomeric structure of 2 in the gas phase, in solution and in the solid state. 相似文献
992.
Sol-Gel Synthesis of Hollow Zinc Ferrite Fibers 总被引:2,自引:0,他引:2
Cairong?Gong Dairong?ChenEmail author Xiuling?Jiao 《Journal of Sol-Gel Science and Technology》2005,35(1):77-82
Hollow zinc ferrite fibers have been prepared via a facile citrate sol-gel process using Fe(OH)(HCOO)2 prepared in laboratory and Zn(CH3COO)2⋅2H2O as the original materials. The obtained hollow fibers were flexible and handlable with the outer diameter being 1–4 μm and the wall thickness less than 1 μm, and the fiber wall were made up of nanoparticles about 50 nm. Rheological behaviour of the precursor sol was tracked by Rheometer. The development of the gel fibers to zinc ferrite fibers was studied by IR, TG and XRD. Morphology observation of the fibers was given on SEM and TEM. 相似文献
993.
A novel two-step aldehyde homologation procedure for the preparation of methyl ketones has been developed, which involves the use of 1,1-dibromo-1-alkenes as precursors and zinc metal as mediator in near-critical water. 相似文献
994.
We have theoretically investigated a series of butadiyne-linked porphyrin derivatives that exhibit large two-photon absorption (TPA) cross sections in the visible-IR range. The electronic structure, one-photon absorption (OPA), and TPA properties have been studied in detail. We found that the introduction of a butadiyne linkage and the increase of the molecular dimensionality from monomer to dimer determine the OPA intensities of Q band and Soret band, respectively. A most important role for the enhancement of the TPA cross section is played by introducing a butadiyne bridge. The complementary coordination and the combination of the terminal free base and the core zinc porphyrin are also two effective factors for the enhancement of the TPA efficiency. The dimer with two porphyrins linked at meso-positions by a butadiyne linkage results in a maximum TPA cross section (79.35 x 10(-48) cm4 s per photon). Our theoretical findings are consistent with the recent experimental observations. This series of porphyrin derivatives as promising TPA materials are the subject of further investigation. 相似文献
995.
研制出复合泡沫塑料色诸柱,并且将其用于可溶性锌(镉)盐的深度纯化,除去重金属杂质离子Fe ̄(2+)、Cr ̄(3+)、Mn ̄(2+)、Pb ̄(2+)、Cu ̄(2+)、Co ̄(2+)和Ni ̄(2+),快速而效果显著。 相似文献
996.
IntroductionDesignandsynthesesofnovelsupramolecularcom plexeswithunusualandtailorablestructuresarefunda mentalstepsindiscoveryandfabricationofvarioustech nologicallyusefulfunctionalsupramoleculardevices .1 3Recently ,considerableeffortshavebeendevotedtocr… 相似文献
997.
The electroreduction of eosin Y on a platinum electrode in deaerated slightly acidic aqueous 0.1 mol L(-1) potassium chloride medium is followed in situ by electron spin resonance (ESR) spectroscopy and UV/Vis spectroscopy. The electrochemical formation of a semiquinone radical is proved by both the appearance of an absorbing band at 408 nm, and a strong ESR signal observed during a negative-going scan. The system is also studied in the presence of Zn(II) ions due to its importance for understanding the growth mechanism of nanostructured ZnO/Eosin Y hybrid films by electrodeposition; under such conditions the ESR and UV/Vis response of the semiquinone radical is not observed. Zinc (II) ions form a complex with the dye, which is reduced by a fast two-electron process. 相似文献
998.
对82名苯作业工人和100名对照组工人的发铁、发锌和发铜含量水平进行了研究。结果揭示,油漆作业工人发铁含量为10.3×10-6±2.3×10-6,明显低于对照组(14.4×10-6±3.1×10-6).P<0.01,发铜含量为7.4×10-6±1.2×10-6,亦低于对照组(9.8×10-6±1.3×10-6).P<0.05;发锌含量为169.2×10-6±26×10-6,与对照组(172.5×10-6±28×10-6)基本相同,P>0.05. 相似文献
999.
K. Györyová V. Balek B. H. Behrens A. Matuschek A. Kettrup 《Journal of Thermal Analysis and Calorimetry》1997,48(6):1263-1271
The new zinc(II) complexes of general formula Zn(CH3CH2CH2COO)2· nL (whereL = caffeine, nicotinamide, theobromine;n=1 or 2) were prepared and identified.Thermal properties of these compounds were investigated by thermal analysis (TG/DTG, DTA, DSC/DDSC).Gaseous products of thermal decomposition were detected by IR spectroscopy and Mass spectroscopy. Final products of thermal decomposition were determined by X-ray powder diffraction patterns.This work was supported by the Slovak Ministry of Education Grant No. 1/3230/96. This financial support is gratefully acknowledged. 相似文献
1000.