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采用半经验的INDO法,首次完成了α-Keggin 结构钼硅四电子杂多蓝K~ 3H~ 5[Simo^v~4-Mo^Ⅵ~8O~4~0].12H~2O量子化学计算,获得102个成键轨道和68 个反键轨道,轨道能级,键序及电荷等数据,证明了杂多酸盐还原产物杂多蓝,还原后Keggin结构阴离子中各原子上电子云密度重新分配,产生一定程度的结构畸变, 但仍保持α-Keggin结构,最高占据轨道由组成分子的各原子轨道组成,其中的桥氧(O~b'O~c)成分较多,表明O~b'O~c为分子中的主要化学活性点HOMO和LUMO为负值, 表明仍可进一步接受电子生成四电子以上的杂多蓝,Muliken分析进一步证明了还原钼原子的位置. 相似文献
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Shunsuke Kotani Masaya Ito Hirono Nozaki Masaharu Sugiura Masamichi Ogasawara Makoto Nakajima 《Tetrahedron letters》2013
An application of a hypervalent silicon complex, generated from a chiral phosphine oxide catalyst and silicon tetrachloride, to the enantioselective organocatalytic Morita–Baylis–Hillman reaction is described. A chloride anion liberated from the hypervalent silicon complex smoothly generated a γ-chloro silyl enol ether that subsequently reacted with an aldehyde to afford the Baylis–Hillman adducts in good yields and with good enantioselectivities. 相似文献
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The compatible carbon-silicon complex materials originated from precursor diglycerylsilane (DGS) and sugar-modified silane
N-(3-triethoxysilylpropyl)gluconamide (GLS) have gained substantial popularity by demonstrating admirable properties to stabilize
entrapped biomolecules. The microenvironment inside these materials, especially the distribution of sugar moieties inside
the matrix, which is likely the most critical factor determining compatibility of these materials, still remains unclear.
To deeply investigate the biocompatibility mechanism of these materials, we have adopted two different preparation routes
for these materials by introducing GLS into the starting DGS sol stage, but things are different after the DGS gel is formed.
A fluorescence probe rhodamine 6G is introduced herein in the DGS sol to monitor the distribution of GLS moieties, as well
as the evolution of the microenvironment inside resulting materials. All in all, the findings demonstrated that the timing
of GLS addition plays a critical role in controlling the evolution of the inner structure of materials, suggesting that this
factor provides a promising route to tune the properties of the resulting materials.
Supported by the National Natural Science Foundation of China (Grant No. 20876176), Scientific Research Foundation for the
Returned Overseas Chinese Scholars by the State Education Ministry, Key Project of Chinese Ministry of Education (Grant No.
109100), Doctoral Project of Shandong Province (Grant No. 2008BS09013), Research Foundation of Key Laboratory of Carbon Materials,
Institute of Coal Chemistry, CAS (Grant No. KFJJ0506), and Natural Science Foundation of Shandong Province (Grant No. Q2007B02) 相似文献
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Kiran Singh Parvesh Puri Yogender Kumar Chetan Sharma 《Phosphorus, sulfur, and silicon and the related elements》2013,188(10):1462-1473
The Schiff bases (imines) HL1 and HL2 have been synthesized by the reaction of 5-bromothiophene-2-carboxaldehyde with 4-amino-5-mercapto-1,2,4-triazole and 4-amino-3-ethyl-5-mercapto-1,2,4-triazole, respectively. Organosilicon(IV) and organotin(IV) complexes having the general formulae R2MCl(L1), R2MCl(L2), R2M(L1)2, R2M(L2)2, (M = Si, Sn; R = CH3) were synthesized by the reaction of R2MCl2 with these Schiff bases in 1:1 and 1:2 molar ratio. The Schiff bases and their metal complexes have been characterized with the aid of elemental analyses, molar conductance, and spectroscopic studies, including UV, IR, 1H, 13C, MS, 29Si, and 119Sn NMR spectroscopy. On the basis of these studies, the resulting complexes have been proposed to have trigonal bipyramidal and octahedral geometries. In vitro activities of the Schiff bases and their metal complexes against some Gram positive and Gram negative bacteria and fungi have been carried out and described. 相似文献
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Mukta Jain Shweta Gaur S. C. Diwedi S. C. Joshi R. V. Singh Anil Bansal 《Phosphorus, sulfur, and silicon and the related elements》2013,188(8):1517-1537
A facile synthesis and studies on the stereochemistry and biochemical aspects of some organosilicon(IV), organotin(IV), and manganese(II) complexes derived from imine having N∪N∪O donor system is reported. The imine was prepared by the condensation of salicylanilide with sulphathiazole. This imine reacts with organosilicon(IV)chloride, organotin(IV)chloride, and hydrated manganese(II) chloride to yield compounds having M─O and M←N bonds. The structures of the compounds have been elucidated by physicochemical and spectral (IR, 1H NMR, 13C NMR, 29Si NMR, 119Sn NMR, and ESR) studies, which clearly point to a trigonal bipyramidal geometry around silicon(IV) and tin(IV), and tetrahedral geometry around manganese(II), as the active lone pair of the nitrogen is also included in the coordination sphere. In the search for better fungicides and bactericides, studies were conducted to assess the growth-inhibiting potential of the synthesized complexes against various pathogenic fungal and bacterial strains. These complexes are highly active against nematode (Meloidogyneincognita) and insect (Trogodermagranarium). The activity will be increased with increasing concentration. These studies demonstrate that the concentrations reached levels that are sufficient to inhibit and kill the pathogens. All compounds have also been found to act as sterilizing agents by reducing the production of sperm in male mice. 相似文献
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《Journal of Coordination Chemistry》2012,65(3-4):219-230
Abstract The ion-association constants between the optically active complex cations (A- or Δ-[Si(phen)3]4+) and the resolving agent anions ([Sb2[(+)-tart]2-]2-, tart = tartrate(4-) ion) were determined spectrophotometrically. Ion-association between the complex cation and the eluent union occurred in two steps and the stereoselective interaction was observed in the second step. The second-step association constant for the A-enantiomer (K 2 = 1.41 × 103) is larger than that for the Δ-enantiomer (K 2 = 1.07 × 103). The second-step association plays a dominant role in determining the elution order in column chromatographic resolution. The molecular mechanics calculations for the ion-associated species were performed to obtain information about the microscopic interaction between the ions. The total strain energy for the species containing the A-enantiomer is smaller than that for the Δ-enantiomer and this can explain the experimental finding that the A-enantiomer is eluted faster than the Δ-enantiomer. 相似文献
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The crystal structure of tetrafluoro(1,10-phenanthroline-N,N')silicon acetonitrile semisolvate, [SiF4(phen)]·1/2CH3CN (I), was studied by X-ray diffraction analysis. The structure of I is tetragonal (space group I41/a; a=9.184(1), c=29.700(5) , Z=8); direct methods, full-matrix least-squares refinement in an anisotropic approximation; R=0.039 for all 1820 independent reflections collected (CAD-4 automatic diffractometer, MoK). The geometrical parameters of the [SiF4(phen)] molecule (bond lengths and angles, etc.) were determined with a high accuracy. 相似文献